Wave B: the native message record — input events, projection, adapter death

The chat record is now pi-native agent history (LhMessage[]), the AI SDK's
UIMessage transcript contract is gone from the server, and every client turn
arrives as ONE explicit input event.

Core (new):
- src/core/native-messages.ts — the LhMessage taxonomy (user/assistant/
  toolResult + lhMarker customs: verdict, probe-handoff, subagent-steer,
  subagent-abort, plan-block), constructors, and toLlmMessages — the single
  model-facing seam (convertToLlm): strips ids, flattens markers to user
  text, drops UI-only plan-blocks, synthesizes INTERRUPTED results for
  dangling aborted calls, never throws.
- src/core/projection.ts — projectNative: the one-way native → UIMessage
  projection (consecutive assistant+toolResult runs group into one
  assistant view message; toolResults attach backward by toolCallId;
  markers project to data parts; plan-blocks splice after the last
  successful plan_init). Every existing consumer reads through it.
- src/core/input-events.ts — the ChatInput union (text/answer/verdict/
  continue), parseChatInput validation, and inputAppends (answer targets
  the dangling question call or 400s; verdict = optional note user
  message + native verdict marker).

Server:
- chat-handler.ts — the turn root takes {chatId, input}; write-ahead
  persists input appends + claimed steers before the turn; claimSteers
  coalesces the whole queue with the handler's steerDelivered filter as
  the dedupe seam; teacher-vs-prober branch on hasProbeDone.
- turn-service.ts — persistTurn stamps ids, drops clean question
  placeholder toolResults (the record ends at the unanswered call),
  emits plan-block markers idempotently (plan-blocks.ts rewrite), and
  persists abort partials.
- ui-stream.ts — PiTurnSpec takes the native base; the wire dialect is
  unchanged. jobs.ts steers are native markers (steer_<jobId> dedup ids);
  waitForIdle reads danglingQuestionOf. teacher-agent.ts wires
  convertToLlm: toLlmMessages. record-adapter.ts DELETED wholesale.
- GET /api/chats/[id] serves messages: projectNative(record.messages).

Client:
- chat-transport.ts — the 409 retry is IDENTITY (re-POST the same event
  body after the turn settles — the event was never persisted
  pre-acceptance; the merge logic is gone). The transport consumes the
  stashed input event via prepareSendMessagesRequest and throws loudly on
  a missing stash.
- chat.tsx — every send call site stashes exactly one ChatInput event
  (text, answer, verdict, continue) before invoking the SDK send.

Tests: full native migration (chat-flow rewritten to input events and
native record pins; jobs/extraction/demos/graph/usage/plan-blocks/
probe-done/reattach-transport converted; record-adapter.test.ts deleted;
chat-transport tests pin the identity retry). 982/982, typecheck, lint,
build all green.

PI-NATIVE-MIGRATION-PLAN.md

@@ -0,0 +1,299 @@
+# Pi-native architecture migration plan
+
+Recon wave 2026-09-26 · READ-ONLY deliverable · `feat/platform` · untracked until owner review
+Evidence: wiretap `/tmp/lh-wire/`, 11 controlled OpenRouter replays (`/tmp/rp-*.json/.out`), pi-ai + pi-agent-core dist sources, pi's own session files under `~/.pi/agent/sessions/`.
+
+---
+
+## 0. Executive summary
+
+- **Two banked facts are overturned by the wiretap evidence** (§1). The tool-stripping mystery was model confabulation — the registry was complete on the wire. The truncation is an upstream (OpenInference) bug triggered by multi-tool-result history volume, not by our serialized shape.
+- Five custom seams mapped against pi-native equivalents (§2). Each has a native replacement; the getApiKey fix (76051d0) is the template: delete the custom seam, use the library path.
+- What genuinely has no native equivalent is small and enumerable (§3): question-tool UX, tool toggles/phases, jobs, prompt overrides, our reattach/persistence infrastructure.
+- Proposed risk order (§4) and test strategy (§5). Seams touching `src/agent` are flagged for Teacher's review per band rules.
+
+---
+
+## 1. Corrections to banked facts (evidence first)
+
+### 1.1 TOOL-SET STRIPPING — SOLVED: the model confabulated; no seam varies the registry
+
+- Wiretap captures **7 and 9 are chat_muhb8l00's two exact turns** (timestamps 18:44:47 / 18:48:10 match the record created 18:44:41Z). **Both carried the full 11-tool registry** — `quiz, ask_user_question, read, ls, find, grep, research, pdf, list_sessions, list_propositions, probe_done` — including the graph tools the model claimed not to have.
+- The response-side capture shows the same request streaming the "no graph tools in this session… the harness is stripped to the two question tools" answer with `finish_reason: stop`. The claim is false; z-ai/glm-5.3-flash (relayed via OpenRouter upstreams Relace/OpenInference) confabulated a toolset, likely trusting prose descriptions over the actual `tools` array.
+- Census of every "missing tool" claim across all master chat records (`data/chats/*.json`):
+  - `chat_mtxsy1lq` (09-12), `chat_mucnl5j3`/`chat_mucnyjvu` (09-22): honest — probe-phase (no graph tools yet) and/or research correctly absent (no search key → `searchAvailable` false).
+  - `chat_mu73galx` (09-18): the closed "no sub-agents" scare (probe-phase prober, teacher tools are teacher-only).
+  - `chat_mufpa030` (09-24): model accurately enumerated its full toolkit; quiz worked.
+  - **"Another session reportedly lacked quiz entirely": not found in any record** (regex census over all chats).
+- Verdict: `tools.ts` gating and `chat-handler`'s ctx passing work as designed. No `src/agent` change required for this mystery (flagged for Teacher anyway since tools.ts is in that band). Mitigation is model-facing (stronger system-prompt tool enumeration, or dropping flash for tool-heavy phases) — an owner decision, not a seam fix.
+
+### 1.2 HISTORY-SERIALIZATION TRUNCATION — REFINED: upstream bug on multi-tool-result histories; our shape is not the trigger
+
+11 controlled replays today against `z-ai/glm-5.3-flash` via OpenRouter (all served by the **OpenInference** upstream; the original truncating request `/tmp/replay.json` = wiretap capture 2, the ML session):
+
+| variant | change vs. truncating request | prompt_tokens | outcome |
+|---|---|---|---|
+| base | verbatim | 7006 | **TRUNC** (4 chunks, ~22 chars reasoning, billed 258 completion, false `finish: stop`) |
+| A | assistant content cleaned (no glued thinking), parallel calls kept | 6803 | **TRUNC** |
+| B | parallel calls split into two sequential assistant turns | 7017 | **TRUNC** |
+| G | `reasoning` param removed | 7006 | **TRUNC** |
+| H | `max_completion_tokens` 131072→8192 | 7006 | **TRUNC** |
+| D | both tool results shortened to ~30 chars | 5982 | works (11 tool calls) |
+| P | two results at 100+100 chars | 6037 | works |
+| L | two results at 300+300 chars | 6201 | **TRUNC** |
+| K | two results at 700+700 chars | 6564 | **TRUNC** |
+| J | big result (1564) + tiny (30) | 6658 | **TRUNC** |
+| E | single result (1564) | 6626 | works |
+| F | single result (802) | 6296 | works |
+| C9 | capture 9 verbatim (the request that streamed the confabulation live) | 6146 | works (332 chars) |
+| I | single result padded to 2764 chars | 7347 | works (4 tool calls) |
+
+Readings:
+- **Not the glued-thinking content** (A truncates clean), **not parallelism** (B truncates sequential), **not prompt size** (I streams 7347 tokens; L truncates at 6201), **not the reasoning param or completion cap** (G, H).
+- **Trigger: ≥2 tool-result messages with combined content ≥ ~200–600 chars** (P works at 200, L truncates at 600, J truncates with 1564+30). A single tool result of any tested size (≤2764 chars) streams fine. Direct Anthropic/OpenAI and non-flash GLM tolerate everything.
+- The failure mode is consistent: a sliver of reasoning streams, 150–260 completion tokens are billed, `finish_reason: stop` arrives with ~zero content — a silent upstream truncation, stable and deterministic 4+ hours after the live capture.
+- **Consequence for the plan:** pi-native serialization would NOT have prevented this — tool results are byte-identical on the wire either way. The live bug needs provider-side action (report to OpenRouter; or pin/avoid the flaky upstream for flash; short-term: route flash traffic elsewhere). The migration below is still correct, for the reasons in §1.3 — but it is not the truncation fix, and saying otherwise would be false comfort.
+
+### 1.3 What IS wrong with our serialization (the honest indictment of record-adapter)
+
+- `src/server/pi/record-adapter.ts:161-163` stamps every replayed assistant message `provider: "openrouter", model: "replayed"` → `transformMessages` (`pi-ai/dist/api/transform-messages.js:66`) sees `isSameModel === false` for **every** replayed turn, forever.
+- Cross-model path converts thinking blocks to plain text (`transform-messages.js:78-81`), which `openai-completions.js` then glues into the assistant content string (no separator — capture 2's content is literally `"<thinking>…question.<text>There's already…"`).
+- `thinkingSignature` cannot survive the UIMessage round-trip (records persist text only), so replayed turns never restore `reasoning_details`. pi's own sessions do: every assistant line in `~/.pi/agent/sessions/**/*.jsonl` carries full `provider/model/api/usage/stopReason` + `thinkingSignature`, which is why pi's replay stays same-model and signature-faithful.
+- Net: every history turn we send diverges from what pi itself would send — discarded reasoning state, cache-hostile, and any provider quirk about reasoning-in-content becomes ours to keep debugging.
+
+---
+
+## 2. Seam-by-seam map: custom remnant → pi-native replacement
+
+### Seam 1 — Message history persistence & replay
+- **Now:** `LHChatRecord` stores Vercel-SDK-shaped UIMessages (part states `input-available`/`output-available`, `data-*` UI parts); `src/server/pi/record-adapter.ts` (`recordToPiMessages`, 189 lines) hand-rebuilds pi-ai `Message[]` per turn; marker-only user messages flatten to canonical text; dangling tool calls get synthesized `INTERRUPTED` results; chat-handler rebuilds history on every POST.
+- **Native:** pi persists append-only JSONL records of full pi-ai messages (verified in pi's own session files); `Agent` accepts `initialState.messages` (`pi-agent-core/dist/agent.js:21-45`); custom message types ride `CustomAgentMessages` declaration-merging (`types.d.ts:269-283`) and are filtered from the LLM view by the default `convertToLlm` (`agent.js:8-10`) or mapped in a `transformContext` hook (`agent-loop.js:179-183`).
+- **Replace with:** store pi `AgentMessage[]` natively in the chat record (custom messages for plan blocks/artifacts/verdict markers instead of `data-*` parts); replay = `initialState.messages` from the store; dangling-call synthesis and marker flattening move into one `convertToLlm`/`transformContext` hook — one place, tested once.
+- **Delete:** `record-adapter.ts` wholesale; the UIMessage part-state model as the history format (UI gets a transcript view model instead).
+- **Kills:** the `model: "replayed"` stamp, thinking-glue, lost signatures (§1.3) — replayed turns become same-model, signature-faithful, cache-friendly.
+
+### Seam 2 — Tool definition wrapper
+- **Now:** `src/agent/lh-tool.ts` (244 lines): `LhTool {name, description, io: zod, execute(args, ctx), clientQuestion}`; `toPiTool` bridges via `z.toJSONSchema`, re-runs zod validation inside `execute` so `superRefine` failures throw `ToolInputError`; `TOOL_TIMEOUT_MS` 30s + 250ms abort grace; `clientQuestion` → `executionMode: "sequential"`.
+- **Native:** `AgentTool` (`pi-agent-core/dist/types.d.ts:340`): required `label`, TypeBox `parameters`, optional `prepareArguments` shim (raw-arg rescue — replaces our re-validation hack), `execute(toolCallId, params, signal, onUpdate)`, per-tool `executionMode`, `replay` policy. pi's own tools are `ToolDefinition`s (`pi-coding-agent/dist/core/extensions/types.d.ts:344`: `promptSnippet`, `promptGuidelines`, `renderCall`, `renderResult`) wrapped by `wrapToolDefinition` (`core/tools/tool-definition-wrapper.js`; reference impl `core/tools/read.js`: TypeBox `Type.Object` schema + snippet/guidelines).
+- **Replace with:** TypeBox-schema ToolDefinitions; `prepareArguments` for arg rescue; timeout stays inside `execute` (it's ours to keep, but as execute internals, not a wrapper layer).
+- **Delete:** `LhTool`, `toPiTool`, the zod→JSON bridge, the `clientQuestion` flag (`executionMode: "sequential"` already expresses it).
+- **Teacher flag:** `src/agent` band.
+
+### Seam 3 — Tool registration gates
+- **Now:** `src/agent/tools.ts` (244 lines): prober/teacher registries, `filterEnabledTools` (drops `enabled[name] === false`), `probe_done` re-added always-on, `research` gated on `searchAvailable`, graph tools gated on `ctx.graphStore`, quiz schema differs per phase.
+- **Native:** registration is plain array assembly (`wrapToolDefinitions`); pi has no gating concept because gating is app policy.
+- **Verdict:** the gating logic itself is app policy, works (§1.1 proved no stripping), and stays — but it assembles ToolDefinitions from seam 2 instead of LhTools. `filterEnabledTools` + toggles map unchanged onto the new shape.
+- **Teacher flag:** `src/agent` band.
+
+### Seam 4 — Question tools & turn stopping
+- **Now:** `src/agent/teacher-agent.ts` `makeStopper` ends the run on a cleanly-resolved question tool call (maxTurns 20 default); question tools `execute` returns a synthetic `'Question posed'` placeholder never persisted; the client renders the question and the learner's answer arrives as the next user message.
+- **Native:** `AgentToolResult.terminate: true` — `agent-loop.js:385` `shouldTerminateToolBatch` stops the loop after a batch whose results all terminate; `types.d.ts:237/330` document the flag; `shouldStopAfterTurn` (`agent-loop.js:154`) covers cross-batch policy.
+- **Replace with:** quiz/ask execute → `{ content, terminate: true }`. Delete `makeStopper`. The pending-question UX (client rendering, answer flow) is app-level and stays as-is.
+- **This is the cleanest example of the whole wave:** our stopper re-implements a library flag.
+
+### Seam 5 — Agent construction & steering
+- **Now:** stateless rebuild per POST (`teacher-agent.ts` — fresh Agent per turn, `composeInstructions` + `effectivePromptSegments` per turn, maxTurns); steering via `claimSteers` coalescing + the wake pipeline's deferred turn.
+- **Native:** stateful `Agent` (`agent.js`): `initialState`, `subscribe` listeners awaited in settlement, `steer()`/`followUp()` queues (`one-at-a-time`/`all` — `steer()` is literally our wake-message semantics), `sessionId` forwarded for cache-aware providers, `thinkingBudgets`, per-agent `toolExecution` default.
+- **Replace with (staged):** keep stateless rebuild first, but feed `initialState.messages` from the native store (seam 1) — same wire, smaller step. A stateful per-chat Agent registry (mirroring `turn-runs.ts`) with `steer()` for the wake path is a later, optional consolidation.
+- **Keep:** `composeInstructions`/prompt overrides (app feature), write-ahead persistence, turn gates.
+- **Teacher flag:** `src/agent` band.
+
+### Seam 6 — SSE / streaming bridge
+- **Now:** `src/server/pi/ui-stream.ts` (423 lines): `runPiTurn` runs the loop, keeps a memory-only chunk log + subscriber set (background-turn wave 00a92e4), and hand-maps pi `AgentEvent`s into the Vercel `UIMessageStream` chunk dialect (text/thinking/toolcall mapping, question-tool output suppression, input gating); `[DONE]` terminal.
+- **Native:** pi events are already a typed stream (`AgentEvent`: `agent_start`/`message_update`/`turn_start`/`turn_end`/`agent_end`, carrying partial+final messages; `pi-ai` `AssistantMessageEventStream` underneath); pi's own client binds via transcript snapshots + event subscriptions (`pi-coding-agent/dist/client/remote-session.js`).
+- **Replace with:** thin passthrough — serialize pi `AgentEvent`s (or message_update partials) directly instead of remapping into UIMessage chunks; keep our subscriber-log/reattach/abort machinery (that's the 00a92e4 background-turn layer and it's good); the question-tool suppression hacks die naturally because native events carry tool-call state honestly.
+- **Cost:** wire dialect changes → **UI stream coordination required** (client half dispatch after merge, same as previous waves).
+- **Delete:** the event-mapping switch in `ui-stream.ts` (the log/subscriber/abort halves stay).
+
+### Already native (the template)
+- `getApiKey` (fixed 76051d0): the deleted hook is exactly this wave's pattern — custom seam removed, pi-ai's native key resolution used. Key-presence gating stays app-side at the turn gate.
+
+---
+
+## 3. What genuinely needs custom (no native equivalent — keep, but express natively)
+
+1. **Question tools awaiting human answers** — closest native is `terminate: true` + app-level answer flow (the "pause the world for a human" semantics is ours).
+2. **Tool toggles / phases / graphTools gating** — app policy at registration time (seam 3).
+3. **Jobs + extraction pipeline** — outside the agent loop entirely; untouched by this wave.
+4. **Prompt override switches** (`composeInstructions`/`effectivePromptSegments`) — app feature; stays.
+5. **Write-ahead persistence, background turns, reattach subscribers, remote abort** — our infrastructure from waves 00a92e4/4d694b3; stays.
+
+---
+
+## 4. Risk order
+
+1. **Wave A — tools + stopping (seams 2+3+4):** smallest blast radius; deletes lh-tool + makeStopper; gates unchanged; UI unaffected (tool names/wire identical).
+2. **Wave B — native history store + replay (seam 1):** biggest win (wire fidelity, signatures, cache, kills §1.3), biggest risk (record migration for existing chats). Needs a one-time record migration + golden-master diff (§5) before cutover.
+3. **Wave C — stateful agents (seam 5, optional):** only after B settles.
+4. **Wave D — SSE dialect (seam 6):** wire contract change; dispatch UI half after merge.
+5. **Independent, immediate:** the §1.2 truncation is an upstream bug — report to OpenRouter / route-pin away from the flaky upstream for `glm-5.3-flash`. Not gated on any wave.
+
+---
+
+## 5. Test strategy
+
+- **Wire-shape pin (kills §1.3 forever):** replay a stored same-model session through `convertMessages` and assert the assistant history carries `reasoning_details`/`thinkingSignature` preserved (fails today on `model: "replayed"`).
+- **Terminate pins:** question tool result `terminate: true` ends the loop natively (replaces `makeStopper` pins; mirror the existing chat-flow scripted-teacher tests).
+- **Registry census pin:** faux-provider wiretap-style test asserting the full registry (11 tools incl. graph tools) is present on the wire for both phases regardless of toggles-off state — pins §1.1 shut.
+- **Golden-master for Wave B:** for every stored chat, diff old adapter output vs native replay output message-by-message before cutover; migrate one throwaway copy of master `data/chats` first (established one-way copy rule).
+- **Per-wave gates unchanged:** typecheck / 950+ tests / lint / build; live smoke on PORT=3004 (faux + real provider), reattach and abort paths re-verified after Wave D.
+
+---
+
+## 6. Open owner decisions
+
+1. Flash-model policy for tool-heavy phases (confabulation §1.1 + truncation §1.2 both bite `z-ai/glm-5.3-flash` via OpenRouter): route-pin, provider-pin, or accept + prompt-mitigate.
+2. Whether to report the OpenInference multi-tool-result truncation to OpenRouter (I can package the 15 replay files as a repro bundle).
+3. Wave B record migration: in-place upgrade vs new-record-format-version with lazy dual-read (settings-delta-wave precedent).
+4. Wave D timing (UI stream coordination).
+
+---
+
+# Wave B planning — native history store + replay (2026-09-26 recon, post-Wave-A)
+
+Wave A landed (93b59cd): tools/stopping are pi-native. Wave B = seam 1 — the
+record becomes pi-native history; `record-adapter.ts` dies. The owner's
+standing rulings already settle the plan's §6.3 (record migration): **zero
+backwards compat, all session data wiped, no migration** — so the golden-master
+cutover is reduced to a fresh-format smoke, not a data project.
+
+## What Wave B replaces today (the seam, precisely)
+
+- `src/server/pi/record-adapter.ts` (189 lines): record→pi-ai rebuild per turn;
+  the `model: "replayed"` stamp (breaks `isSameModel` forever — §1.3), thinking
+  glued into content, `thinkingSignature` lost (records persist text only),
+  verdict/handoff marker flattening (`systemTextOf`), dangling-call
+  INTERRUPTED synthesis.
+- `chat-handler`: write-ahead persist of the CLIENT's full UIMessage list (the
+  client owns the transcript between turns — useChat resend + addToolOutput),
+  `recordToPiMessages(outgoing)` at agent build, probe_done detection over
+  UIMessage parts.
+- `ui-stream.runPiTurn`: assembles UIMessage parts from pi events; that
+  assembly is BOTH the wire dialect (Wave D's concern) AND the persist target.
+- `turn-service`: `withMessageIds` (SDK client-side-id patch), plan-block
+  attachment onto UIMessage parts.
+
+## Consumer census (who reads record.messages as UIMessage part shapes)
+
+Server/core: phases (`phaseAt3` — tool-probe_done part state), pending
+(`findPendingToolCall`), plan-blocks (`withPlanBlocks`), coverage
+(`coverageOf`), graph extraction sources (`toolParts`), extraction
+(`messageViewLines`), store summaries (phase + pendingQuestion),
+`/api/chats/[id]` GET, jobs.ts (steers as data-part messages; `claimSteers`
+over the POST body). Client: `useChat` POSTs the full list, renders every
+part type, `mergeAdopted`, addToolOutput answers, artifact/plan/abort cards.
+**None of these need the STORAGE to be UIMessage — they need a UIMessage-SHAPED
+VIEW.** That distinction is Wave B's core move.
+
+## The design: server-owned native record + one-way projection
+
+1. **`LHChatRecord.messages: AgentMessage[]`** (pi-ai `UserMessage |
+   AssistantMessage | ToolResultMessage | CustomMessage`). The agent's own
+   final messages persist at `message_end` — provider/model/usage/stopReason/
+   thinkingSignature stamped by the loop itself (what pi persists in its own
+   sessions). §1.3 dies by construction: replayed turns are byte-faithful,
+   same-model, signature-preserving; replay = `state.messages` assignment,
+   zero conversion.
+2. **Custom messages for our non-LLM content** (pi's `CustomMessage`: role
+   "custom", customType, content, display, details): plan-block,
+   subagent-artifact, subagent-aborted, question-answered markers. The
+   verdict/probe-handoff steers persist AS custom messages whose CONTENT is
+   the canonical model-facing text (verdictText / HANDOFF_TEXT written once
+   at append) — `systemTextOf` flattening disappears; `convertToLlm` default
+   passes content through, UI-only types filter via details/customType.
+3. **One-way projection `AgentMessage[] → UIMessage[]`** (new
+   `src/server/pi/project.ts`): serves `/api/chats/[id]` GET, the summary
+   scans (phase/pending/coverage/plan-blocks/graph/extraction keep their
+   existing UIMessage code — they read the projection), and the client until
+   Wave D. The lossy DIRECTION (UIMessage→pi) is deleted; the projection is
+   Wave D's deletion target.
+4. **Question answers are native tool results (owner ruling, 2026-09-26).**
+   The history stays a NORMAL agent history: quiz toolCall followed by its
+   toolResult — the process just stops in between. The placeholder result
+   is an in-memory loop device only (terminate:true ends the turn); it is
+   never persisted, exactly as today's wire suppression. On answer, the
+   server appends a native ToolResultMessage whose content is the same
+   encoding the adapter produces today (the model-facing wire is
+   byte-shape-identical to current behavior). The record carries the
+   dangling call only in the pose→answer window, where no turn can run
+   (the question gate holds steers), and the INTERRUPTED synthesis survives
+   solely for the abort case — same as today. pi's own resume path is the
+   mechanism: assign state.messages (record ending at the toolResult),
+   continue().
+5. **Turn input contract**: the POST body's new-content DELTA (new user text,
+   answers, markers) is appended natively; the full-list body stays for now
+   (client unchanged — see fork 3).
+
+## Forks — ALL RESOLVED (owner rulings, 2026-09-26)
+
+1. **Answer semantics — normal agent history.** The answer is the tool
+   call's toolResult, appended natively at answer time; the placeholder is
+   an in-memory loop device only (terminate), never persisted. No custom
+   answer markers. Verified against pi's source: the loop always pairs
+   calls with results in a RUN, but the record may end at the assistant
+   message (no turn can run in the pose→answer window — the question gate
+   holds steers); pi's own resume path (assign state.messages, continue()
+   from the toolResult) is the mechanism. The model-facing wire is
+   byte-shape-identical to today.
+2. **Storage shape — `AgentMessage[]` inside LHChatRecord JSON.** No new
+   dependencies; metadata stays in the one atomic tmp+rename file. (pi
+   SessionManager JSONL rejected: pi-coding-agent is a 139MB harness dep
+   and its tree/branching/compaction machinery is unused here.)
+3. **POST contract — input events NOW, in this pass** (owner overrode the
+   server-side-delta recommendation): POST /api/chat carries
+   `{chatId, input}` where input is one of:
+   `{type:"text", text, note?}` (composer send; note rides the pending
+   verdict interplay),
+   `{type:"answer", toolCallId, answer:{values,other,text,dontKnow,note},
+   dismissed?}` (quiz/ask answer or dismissal — graded client-side as
+   today, the structured verdict becomes the native toolResult content),
+   `{type:"verdict", accepted, note?}` (plan verdict).
+   Consequences: the client's 409 merge-retry DIES (nothing to merge — a
+   409 means wait-and-retry the same idempotent event); claimSteers/
+   write-ahead of full lists dies; the wake pipeline's internal turns
+   (setTurnRunner) and jobs steers append natively server-side; useChat
+   stays as the RENDERER (message list = projected record + stream
+   assembly — receive side unchanged until Wave D); sends go through a
+   thin client session-client: POST the event, read the status, cancel
+   the 200 body (a view may detach freely — the turn runs on), then
+   attach via the standard resume path. Client touches: chat-transport
+   send half, chat.tsx call sites (composer, onSubmitAnswer, verdict,
+   dismiss). Receive half (SSE dialect, part rendering) stays Wave D.
+4. **Raw vs validated tool args — resolved by design**: persist pi's own
+   AssistantMessage verbatim (what message_end carries). That means RAW
+   streamed args — byte-faithful replay, identical to what pi persists in
+   its own sessions, cache-parity with the original emission. The dock's
+   parse seam already tolerates raw (Wave A boundaryParse fix); no other
+   record consumer reads tool-call args.
+5. **Abort semantics — folded into 1**: persist partial (current
+   behavior); the record ends at the dangling call for the abort case and
+   the INTERRUPTED synthesis at replay covers it (same as today).
+
+## Test strategy
+
+- Wire-shape pin (§5's oldest promise, now trivial): persist a scripted
+  session's agent messages, rebuild the agent, `convertMessages` → assert
+  `provider`/`model` real (not "replayed"), `thinkingSignature` present.
+- Projection parity: every existing UIMessage consumer test (988 suite) runs
+  against the projection unchanged — the suite IS the golden master.
+- Question flow: pose → answer-as-marker → next turn's model view carries the
+  verdict; abort mid-question → resume works (kills the synthesis tests).
+- Live smoke: real turn + reattach + remote abort on PORT=3004.
+
+## Blast radius (files)
+
+Delete: record-adapter.ts; chat-transport's retryingFetch/merge logic.
+New: project.ts (AgentMessage[]→UIMessage projection), input-events
+contract (core/contracts), client session-client send module.
+Rewrite: chat-handler (build = state.messages from record; input-event
+append; probe_done detection over native messages), ui-stream (part
+assembly becomes WIRE-ONLY; the record write comes from the agent's own
+messages at message_end), turn-service (native appends replace
+withMessageIds/withPlanBlocks part mutation; plan-blocks/artifact steers
+become CustomMessages), store/chats + core scanners (phaseAt3,
+findPendingToolCall, coverage, graph sources — read the projection,
+mechanical), jobs.ts (steers append native CustomMessages; setTurnRunner
+internal path), client send call sites (composer, onSubmitAnswer, verdict,
+dismissal — chat-transport send half). useChat's RECEIVE half and all part
+renderers untouched (Wave D). Agent band untouched (Wave A's). Wave C
+(steer() consolidation) stays deferred.

app/api/chats/[id]/route.ts

@@ -1,4 +1,5 @@
 import { deleteChatSession, getChat, isTurnRunning, sessionCoverage, stores, type ChatDeleteMode } from "@/src/server";
+import { projectNative } from "@/src/core";
 
 export async function GET(_req: Request, { params }: { params: Promise<{ id: string }> }) {
 	const { id } = await params;
@@ -10,7 +11,16 @@ export async function GET(_req: Request, { params }: { params: Promise<{ id: str
 	// meter + sidebar block — THE coverage surface (the all-sessions GET
 	// route died with the redesign; the Extract POST stays). getChat
 	// already 404'd, so the block exists.
-	return Response.json({ ...chat, turnInFlight: isTurnRunning(id), coverage: sessionCoverage(id) });
+	// Wave B (owner-approved 2026-09-26): the record's messages are native
+	// agent history — clients receive the one-way projection (the AI-SDK
+	// UIMessage view) until Wave D. turnInFlight lets a returning client
+	// re-attach to a running turn; coverage is the chat view's ring meter.
+	return Response.json({
+		...chat,
+		messages: projectNative(chat.messages),
+		turnInFlight: isTurnRunning(id),
+		coverage: sessionCoverage(id),
+	});
 }
 
 /**

app/chat/[id]/page.tsx

@@ -1,6 +1,6 @@
 import { notFound } from "next/navigation";
 import { Chat } from "@/components/chat";
-import { slotsConfigured, type TeacherUIMessage } from "@/src/core";
+import { projectNative, slotsConfigured, type TeacherUIMessage } from "@/src/core";
 import { getChat, isTurnRunning, readSettingsRecord } from "@/src/server";
 
 export const dynamic = "force-dynamic";
@@ -24,7 +24,9 @@ export default async function ChatPage({
 			key={chat.id}
 			chatId={chat.id}
 			title={chat.title}
-			initialMessages={chat.messages as TeacherUIMessage[]}
+			// Wave B: the record is native history — the client view is the
+				// one-way projection (GET /api/chats/[id] serves the same shape).
+				initialMessages={projectNative(chat.messages) as TeacherUIMessage[]}
 			initialConfigured={slotsConfigured(record?.models)}
 			initialPrompt={prompt}
 			// A teacher turn that outlived its client: the remounted view must

components/chat-transport.ts

@@ -1,28 +1,31 @@
 /**
- * Chat transport with 409 merge-retry — the learner's send can race the
+ * Chat transport for the INPUT-EVENTS contract (Wave B, owner ruling
- * server's wake pipeline (contracts/jobs.ts "THE ASYNC PROTOCOL"): the wake
+ * 2026-09-26): the client never re-POSTs its transcript — every send
- * turn starts server-side and the client only notices via the /api/jobs poll
+ * carries ONE explicit input event ({text} | {answer} | {verdict} |
- * up to a second later. A send in that window gets 409'd ("a turn is already
+ * {continue}) stashed by the call site (chat.tsx) before invoking the SDK
- * running") and, before this file, surfaced as an error banner.
+ * send. The server owns the record; this transport's ONLY send-time job is
+ * to consume the stash and put it on the wire as {chatId, input}.
  *
- * Why NOT a bare retry: every 409 means the server record is AHEAD of the
+ * 409 retry (the wake-pipeline race, contracts/jobs.ts "THE ASYNC
- * client — the wake turn persisted the steer message (and, once it finishes,
+ * PROTOCOL"): a send can race the server's wake turn (the client only
- * its response) that the client hasn't seen. The chat handler's write-ahead
+ * notices it via the /api/jobs poll up to a second later) and gets
- * persist makes the request body the canonical transcript, so re-POSTing the
+ * 409'd. Under input events the retry is IDENTITY: the event was never
- * stale client list would clobber the steer + wake messages out of the
+ * persisted (the write-ahead only happens once the turn is accepted), so
- * record (and the job already flipped done — steerDelivered makes
+ * waiting for the in-flight turn and re-POSTing the SAME body is safe —
- * re-delivery impossible: permanent loss). The retry must therefore MERGE:
+ * no merge, no stale-list clobber. The old UIMessage-era merge logic is
- * wait for the in-flight turn to finish, refetch the record, append the
+ * deleted with the UIMessage record (the server now owns the
- * client's unsent messages (by id) to the server's list, and re-POST the
+ * record; a lost race means "try again later", not "merge transcripts").
- * merged transcript.
  *
- * Client-side gap after a merged retry: useChat's local list still lacks the
+ * The send path is LOUD about a missing stash: every SDK send must map to
- * steer/wake messages until the next syncFromServer (job settle, remount, or
+ * exactly one event — a send with nothing stashed is a call-site bug
- * a future "server-ahead" heal in the poller). Rare path; self-heals.
+ * (it would otherwise silently re-send the previous event), so the
+ * transport throws instead of guessing.
  */
+
 import { DefaultChatTransport } from "ai";
 import type { UIMessageChunk } from "ai";
 import type { ChatTransport } from "ai";
+import type { ChatInput } from "@/src/core";
 import type { TeacherUIMessage } from "@/src/core";
 
 /** How often to poll turnInFlight while the racing turn runs. */
@@ -56,21 +59,10 @@ async function turnInFlight(chatId: string): Promise<boolean | null> {
 	}
 }
 
-async function serverMessages(chatId: string): Promise<TeacherUIMessage[] | null> {
-	try {
-		const res = await fetch(`/api/chats/${encodeURIComponent(chatId)}`);
-		if (!res.ok) return null;
-		const record = (await res.json()) as { messages?: TeacherUIMessage[] };
-		return Array.isArray(record.messages) ? record.messages : null;
-	} catch {
-		return null;
-	}
-}
-
 /**
- * A fetch that turns a 409 on POST /api/chat into: wait for the running turn,
+ * A fetch that turns a 409 on POST /api/chat into: wait for the running
- * merge the outgoing messages onto the fresh server record, re-POST. Non-409
+ * turn, re-POST the SAME event body. Non-409 responses pass through
- * responses pass through untouched.
+ * untouched.
  */
 /** Exported for tests. */
 export function retryingFetch(chatId: string, opts: RetryFetchOptions = {}): typeof globalThis.fetch {
@@ -90,36 +82,15 @@ export function retryingFetch(chatId: string, opts: RetryFetchOptions = {}): typ
 			if (init?.signal?.aborted) return response;
 			if ((await turnInFlight(chatId)) !== false) continue;
 
-			// Turn finished: merge onto the fresh record, then re-POST.
+			// Turn finished: re-POST the same input event — nothing merged,
-			const record = await serverMessages(chatId);
+			// nothing lost (the event was never persisted pre-acceptance).
-			if (!record || typeof init?.body !== "string") return response;
+			response = await fetch(input, init); // may 409 again → loop
-			const serverIds = new Set(record.map((m) => m.id));
-			const body = JSON.parse(init.body) as { messages?: TeacherUIMessage[] };
-			if (!Array.isArray(body.messages)) return response;
-			const outgoing = body.messages.filter((m) => m.id && !serverIds.has(m.id));
-			const merged = JSON.stringify({ ...body, messages: [...record, ...outgoing] });
-
-			response = await fetch(input, { ...init, body: merged }); // may 409 again → loop
 		}
 
 		return response;
 	};
 }
 
-/**
- * The plain transport (no reattach adapters): sends keep the 409
- * merge-retry. chat.tsx uses createReattachingTransport below — a
- * superset of this — but the plain form stays exported for surfaces
- * that only ever send (never resume onto a running turn).
- */
-export function createChatTransport(chatId: string): DefaultChatTransport<TeacherUIMessage> {
-	return new DefaultChatTransport<TeacherUIMessage>({
-		api: "/api/chat",
-		body: { chatId },
-		fetch: retryingFetch(chatId),
-	});
-}
-
 /* ────────────────────────────────────────────────────────────────────────
  * THE REATTACH TRANSPORT (background-turn runner wave, owner ruling
  * 2026-09-25): a turn runs server-side decoupled from every view, and a
@@ -166,6 +137,14 @@ export interface ReattachOptions {
 	lastMessageId?: () => string | undefined;
 }
 
+/** The input-events half (Wave B): consume the call site's stashed event.
+ *  Exactly one event per SDK send — the ref is cleared on read, so a
+ *  send with nothing stashed fails LOUDLY rather than re-sending the
+ *  previous event. */
+export interface InputEventOptions {
+	takeInput: () => ChatInput | undefined;
+}
+
 /** Concatenate byte payloads (the head stream's event + read-past remainder). */
 function concatBytes(a: Uint8Array, b: Uint8Array): Uint8Array {
 	const out = new Uint8Array(a.length + b.length);
@@ -179,7 +158,7 @@ function freshMessageId(): string {
 	return `msg_${Date.now().toString(36)}_${crypto.randomUUID().slice(0, 8)}`;
 }
 
-/** One parsed SSE event off the wire (data: <json>\\n\\n framing). */
+/** One parsed SSE event off the wire (data: <json>\n\n framing). */
 interface SseEvent {
 	/** The raw bytes of this event, re-injectable into the head stream. */
 	raw: Uint8Array;
@@ -193,7 +172,7 @@ interface SseEvent {
 /**
  * Read the FIRST complete SSE event off a live body (the settled terminal
  * and the start chunk are both single small events; a long-lived turn's
- * log replays after). Resolves as soon as one \\n\\n boundary is seen — the
+ * log replays after). Resolves as soon as one \n\n boundary is seen — the
  * caller re-injects the raw bytes (plus any read-past remainder) ahead of
  * the unconsumed tail, so nothing is lost or reordered.
  */
@@ -217,10 +196,11 @@ async function readFirstEvent(reader: ReadableStreamDefaultReader<Uint8Array>):
 	}
 }
 
-/** The reattach transport: DefaultChatTransport for sends, our seam for resumes. */
+/** The reattach transport: the input-event POST for sends, our seam for resumes. */
 class ReattachingChatTransport extends DefaultChatTransport<TeacherUIMessage> {
 	constructor(
 		private readonly reattach: ReattachOptions,
+		private readonly inputEvent: InputEventOptions,
 		init: ConstructorParameters<typeof DefaultChatTransport<TeacherUIMessage>>[0],
 	) {
 		super(init);
@@ -300,15 +280,31 @@ class ReattachingChatTransport extends DefaultChatTransport<TeacherUIMessage> {
 
 /**
  * The chat.tsx wiring: `transport: createReattachingTransport(chatId, refs)`.
- * Sends keep the 409 merge-retry fetch; resumes take the adapters above.
+ * Sends POST the stashed input event with the 409 identity-retry fetch;
+ * resumes take the adapters above.
  */
 export function createReattachingTransport(
 	chatId: string,
 	reattach: ReattachOptions,
+	inputEvent: InputEventOptions,
 ): DefaultChatTransport<TeacherUIMessage> {
-	return new ReattachingChatTransport(reattach, {
+	return new ReattachingChatTransport(reattach, inputEvent, {
 		api: "/api/chat",
 		body: { chatId },
 		fetch: retryingFetch(chatId),
+		// THE INPUT-EVENTS CONTRACT (Wave B): replace the SDK's full-transcript
+		// body with {chatId, input}. The stash is consumed HERE — exactly once
+		// per SDK send (the 409 retry re-POSTs the built body, not the stash);
+		// a send with nothing stashed fails LOUDLY (a call-site bug — it must
+		// never silently re-send the previous event).
+		prepareSendMessagesRequest: () => {
+			const input = inputEvent.takeInput();
+			if (!input) {
+				throw new Error(
+					"Send without a stashed input event — every send call site must set pendingInput before invoking the SDK send (Wave B input-events contract).",
+				);
+			}
+			return { body: { chatId, input } };
+		},
 	});
 }

components/chat.tsx

@@ -26,7 +26,7 @@ import { DictationBar, useDictation } from "@/components/dictation";
 import { JobsContext } from "@/components/jobs-context";
 import { StatsBar } from "@/components/stats-bar";
 import { useActivity } from "@/components/activity-dock";
-import { isProviderKeyRefusal, mergeAdopted, type ChatSettings, type ModelSlotName } from "@/src/core";
+import { isProviderKeyRefusal, mergeAdopted, type ChatInput, type ChatSettings, type ModelSlotName } from "@/src/core";
 import { PlanBlock, PlanPopup, latestTree } from "@/components/plan-block";
 import { PlanMarginalia } from "@/components/plan-window";
 import { MermaidOverlay, SessionMermaidContext } from "@/components/session-overlay";
@@ -181,15 +181,35 @@ export function Chat({
 	// the per-render transport recreation can never capture a stale one.
 	const reattachSettledRef = useRef<() => void>(() => {});
 	const reattachLastIdRef = useRef<string | undefined>(undefined);
+	// THE INPUT STASH (Wave B input-events contract, owner ruling
+	// 2026-09-26): every SDK send maps to EXACTLY ONE explicit input event —
+	// the call site stashes the event here before invoking the SDK send, and
+	// the transport consumes it when building the POST body ({chatId, input};
+	// the client transcript never rides the wire). Consumed-on-read: a send
+	// with nothing stashed fails LOUDLY in the transport (a call-site bug —
+	// it must never silently re-send the previous event).
+	const pendingInputRef = useRef<ChatInput | null>(null);
+	const stashInput = (input: ChatInput) => {
+		pendingInputRef.current = input;
+	};
+	const takeInput = () => {
+		const input = pendingInputRef.current;
+		pendingInputRef.current = null;
+		return input ?? undefined;
+	};
 
 	const { messages, sendMessage, addToolOutput, setMessages, status, error, stop, clearError, resumeStream } =
 		useChat<TeacherUIMessage>({
 			id: chatId,
 			messages: initialMessages,
-			transport: createReattachingTransport(chatId, {
+			transport: createReattachingTransport(
+				chatId,
+				{
 					onSettled: () => reattachSettledRef.current(),
 					lastMessageId: () => reattachLastIdRef.current,
-			}),
+				},
+				{ takeInput },
+			),
 			// After the learner answers (addToolOutput), automatically send the
 			// continuation request so the teacher reacts to the answer.
 			sendAutomaticallyWhen: lastAssistantMessageIsCompleteWithToolCalls,
@@ -200,6 +220,7 @@ export function Chat({
 	useEffect(() => {
 		if (!sentInitial.current && initialPrompt && initialMessages.length === 0) {
 			sentInitial.current = true;
+			stashInput({ type: "text", text: initialPrompt });
 			void sendMessage({ text: initialPrompt });
 		}
 	}, [initialPrompt, initialMessages.length, sendMessage]);
@@ -343,6 +364,7 @@ export function Chat({
 			messages.length > 0 &&
 			lastAssistantMessageIsCompleteWithToolCalls({ messages })
 		) {
+			stashInput({ type: "continue" });
 			void sendMessage();
 		}
 		// mount-only by design (turnInFlight read at initial value)
@@ -492,6 +514,7 @@ export function Chat({
 			status === "ready" &&
 			lastAssistantMessageIsCompleteWithToolCalls({ messages: record.messages })
 		) {
+			stashInput({ type: "continue" });
 			void sendMessage();
 		}
 	}, [chatId, setMessages, sendMessage, status]);
@@ -612,8 +635,8 @@ export function Chat({
 			// TWO REAL MESSAGES, ONE TURN (the custom-message scheme, user-decided
 			// 2026-09-12): a typed note is the learner's own user message, and the
 			// verdict is its own custom message — marker part ONLY, no human-
-			// authored text (the model-facing wording lives in the adapter:
+			// authored text (the model-facing wording lives in toLlmMessages,
-			// record-adapter flattens it; nothing fake is persisted as speech).
+			// the native convertToLlm seam; nothing fake is persisted as speech).
 			// setMessages + sendMessage() (no args) fires ONE request carrying
 			// both — the same single-turn mechanism syncFromServer already uses,
 			// so no 409 dance and no double teacher turn.
@@ -639,6 +662,10 @@ export function Chat({
 				],
 			});
 			setMessages([...messages, ...appended]);
+			// The event (Wave B): the server appends the note (its own user
+			// message) + the verdict marker natively — the optimistic ids above
+			// are local render only; the settle sync lands the canon.
+			stashInput({ type: "verdict", accepted, note: note || undefined });
 			void sendMessage();
 		},
 		[text, messages, setMessages, sendMessage],
@@ -964,6 +991,7 @@ export function Chat({
 		if (!t || busy || pending) return;
 		draftRef.current = t; // the refusal flow's preserve-and-replay seam
 		setText("");
+		stashInput({ type: "text", text: t });
 		void sendMessage({ text: t });
 	};
 
@@ -972,7 +1000,10 @@ export function Chat({
 			value={{
 				chatId,
 				syncFromServer,
-				sendText: (t: string) => void sendMessage({ text: t }),
+				sendText: (t: string) => {
+					stashInput({ type: "text", text: t });
+					void sendMessage({ text: t });
+				},
 				openSetup: () => setSetupOpen(true),
 			}}
 		>
@@ -1318,6 +1349,7 @@ export function Chat({
 				if (t) {
 					setText("");
 					draftRef.current = t;
+					stashInput({ type: "text", text: t });
 					void sendMessage({ text: t });
 				}
 			}}

src/agent/subagents/extraction.ts

@@ -28,6 +28,7 @@ import { getGraph, mergeFindings, type EmissionStats, type GraphDeps } from "../
 import type { GraphStore } from "../../core/ports.ts";
 import { settleGraphLayout } from "../../core/layout-settle.ts";
 import { batchRuns, batchTag, coverageOf, messageViewLines } from "../../core/coverage.ts";
+import { projectNative } from "../../core/projection.ts";
 
 /**
  * The extraction pipeline (vision §1 construction, 2026-09-02 redesign) — the
@@ -92,10 +93,12 @@ import { batchRuns, batchTag, coverageOf, messageViewLines } from "../../core/co
 export function transcriptView(record: ChatRecord): string {
 	// The shared seam (core/coverage.ts messageViewLines): the LLM's prompt
 	// view and the coverage fingerprint use ONE line builder, so "covered"
-	// means — exactly — what the extractor saw.
+	// means — exactly — what the extractor saw. Wave B: the record is native
+	// history — the extraction view reads through the one-way projection.
 	const lines = [`SESSION: ${record.title}`];
-	record.messages.forEach((message, index) => {
+	const projected = projectNative(record.messages);
-		lines.push(...messageViewLines(message as UIMessage, (message as UIMessage).id || `m${index}`));
+	projected.forEach((message, index) => {
+		lines.push(...messageViewLines(message, message.id || `m${index}`));
 	});
 	return lines.join("\n");
 }
@@ -868,7 +871,8 @@ export function createExtractionPipeline(deps: ExtractionPipelineDeps): Extracti
 			// engines AND their providers' keys; a refusal lands BEFORE any
 			// stage runs (typed — the trigger skips, routes surface 503).
 			refuseIfStagesUnready();
-			const covered = coverageOf(record.messages as UIMessage[], graphStore.readCoverage(), chatId);
+			const projected = projectNative(record.messages);
+			const covered = coverageOf(projected, graphStore.readCoverage(), chatId);
 			if (covered.uncovered.length === 0) {
 				console.info(`[extraction ${chatId}] nothing uncovered — no-op`);
 				return { nodes: 0, edges: 0, events: 0 };
@@ -883,11 +887,11 @@ export function createExtractionPipeline(deps: ExtractionPipelineDeps): Extracti
 				// The batch's prompt view: SESSION header + the batch's lines,
 				// same provenance [id] tags the fingerprints used (coverage
 				// and prompt share ONE line builder — core/coverage.ts).
-				const mids = record.messages.map((m, i) => ((m as UIMessage).id || `m${i}`) as string);
+				const mids = projected.map((m, i) => (m.id || `m${i}`) as string);
 				const view = [
 					`SESSION: ${record.title}`,
 					...batch.flatMap((slot) => {
-						const idx = record.messages.indexOf(slot.message);
+						const idx = projected.indexOf(slot.message);
 						return messageViewLines(slot.message, mids[idx] ?? slot.message.id);
 					}),
 				].join("\n");

src/agent/subagents/runner.ts

@@ -1,4 +1,4 @@
-import { isToolUIPart, type UIMessage } from "ai";
+import { isToolUIPart } from "ai";
 import type { PiEngine } from "../models.ts";
 import type { SearchProvider } from "../../core/search.ts";
 import {
@@ -14,7 +14,7 @@ import {
 	type PdfToolInput,
 	type ResearchResult,
 	type ResearchToolInput,
-	type SubagentSteerMessage,
+	type SteerMessage,
 	type UsageStepLike,
 	type VisualResult,
 	type VisualToolInput,
@@ -23,6 +23,8 @@ import { registerJobAbort, unregisterJobAbort } from "./aborts.ts";
 import type { ModelRole } from "../../../config.ts";
 import { ROLE_SLOT, modelsNotConfigured, type ModelSlotName, type ProviderKeyMissing } from "../../core/settings.ts";
 import type { ChatStore, JobStore } from "../../core/ports.ts";
+import { projectNative } from "../../core/projection.ts";
+import type { UIMessage } from "ai";
 import { runDemoBuilder } from "./demo-builder.ts";
 import { runPdfReaderAgent } from "./pdf-reader.ts";
 import { runResearcherAgent } from "./researcher.ts";
@@ -69,7 +71,7 @@ export interface JobRunnerDeps {
 	 * steer is delivered (the wake turn completed and the job status
 	 * flipped); rejects when delivery fails unrecoverably.
 	 */
-	deliver: (steer: SubagentSteerMessage) => Promise<void>;
+	deliver: (steer: SteerMessage) => Promise<void>;
 	/** Settings-resolved engine per role (model slots wave, 2026-09-20):
 	 *  the role-override → slot chain, read FRESH per job (the server
 	 *  wiring passes effectiveSettings-based resolution). Test overrides
@@ -274,7 +276,11 @@ export function createJobRunner(deps: JobRunnerDeps): JobRunner {
 		if (input) return input;
 		const chat = chatStore.getChat(job.chatId);
 		if (!chat) return undefined;
-		return (findToolPart(chat.messages, job.toolCallId)?.input ?? undefined) as JobToolInput | undefined;
+		// Wave B: the record is native history — the transcript scan reads
+		// through the projection (same shape the old record held).
+		return (findToolPart(projectNative(chat.messages), job.toolCallId)?.input ?? undefined) as
+			| JobToolInput
+			| undefined;
 	}
 
 	// ─── shared plumbing ────────────────────────────────────────────────────

src/agent/teacher-agent.ts

@@ -15,6 +15,7 @@ import {
 } from "./tools.ts";
 import { quizInputObject, quizInputProblems } from "../core/question-core.ts";
 import { QUESTION_TOOLS, type EnabledTools } from "../core/pending.ts";
+import { toLlmMessages } from "../core/native-messages.ts";
 
 /**
  * The two teaching-side agents (docs/probe-teach-split.md): the PROBER and
@@ -89,7 +90,7 @@ export type StepUsageCollector = (usage: Usage) => void;
 export interface AgentBuildOptions {
 	/** Model + stream function — tests inject a scripted faux engine. */
 	engine?: PiEngine;
-	/** The initial transcript, as pi messages (recordToPiMessages). */
+	/** The initial transcript, as pi messages (the record IS agent state). */
 	messages?: AgentMessage[];
 	/** Money channel: one call per model request. */
 	onUsage?: StepUsageCollector;
@@ -164,6 +165,13 @@ function baseAgentOptions(kind: AgentKind, opts: AgentBuildOptions, tools: Agent
 		},
 		streamFn: engine.streamFn,
 		shouldStopAfterTurn: stopper,
+		// Wave B (owner-approved 2026-09-26): the model-facing conversion is
+		// THE app seam — markers flatten to their canonical user text
+		// (verdictText / HANDOFF_TEXT / steer text, all single-sourced),
+		// UI-only markers (plan-block) drop, the app's id fields strip, and
+		// an abort's dangling question call gets its INTERRUPTED result. It
+		// must never throw (pi's convertToLlm contract).
+		convertToLlm: toLlmMessages,
 	});
 	if (opts.onUsage) {
 		agent.subscribe((event: AgentEvent) => {

src/agent/tools/probe.ts

@@ -1,10 +1,9 @@
 import type { AgentTool } from "@earendil-works/pi-agent-core";
 import { serverExecute } from "../tool-execute.ts";
 import { probeDoneInputSchema, type ProbeDoneResult } from "../../core/contracts.ts";
-import type { UIMessage } from "ai";
+import { danglingQuestionOf, hasProbeDone, type LhMessage } from "../../core/native-messages.ts";
-import { findPendingToolCall } from "../../core/pending.ts";
 import type { ChatStore } from "../../core/ports.ts";
-import { buildProbeHandoffSteer, type ProbeHandoffSteerMessage } from "../../core/contracts.ts";
+import { buildProbeHandoffSteer, type SteerMessage } from "../../core/contracts.ts";
 
 /** What the probe_done tool closes over. */
 export interface ProbeDoneContext {
@@ -13,15 +12,14 @@ export interface ProbeDoneContext {
 	chatStore: ChatStore;
 	/** Queue the handoff steer (the wake pipeline — src/server/jobs.ts).
 	 *  Injected so this module never imports the server seam. */
-	deliver: (steer: ProbeHandoffSteerMessage) => void;
+	deliver: (steer: SteerMessage) => void;
 }
 
-/** Does the transcript already carry a concluded probe (any state)? */
+/** Does the transcript already carry a concluded probe (any state)?
-function probeConcluded(messages: UIMessage[]): boolean {
+ *  Wave B: the native scan (any probe_done tool call, any state) — same
-	for (const m of messages) {
+ *  semantics the UIMessage part scan had. */
-		if (m.parts.some((p) => p.type === "tool-probe_done")) return true;
+function probeConcluded(messages: readonly LhMessage[]): boolean {
-	}
+	return hasProbeDone(messages);
-	return false;
 }
 
 /**
@@ -64,7 +62,7 @@ export function probeDoneTool(ctx: ProbeDoneContext): Record<string, AgentTool<a
 				const record = ctx.chatStore.getChat(ctx.chatId);
 				if (!record) return { ok: false, error: `Chat not found: ${ctx.chatId}` };
 
-				if (findPendingToolCall(record.messages) !== null) {
+				if (danglingQuestionOf(record.messages) !== null) {
 					return {
 						ok: false,
 						error:

src/core/contracts/chat.ts

@@ -8,22 +8,27 @@
  */
 import type { UIMessage } from "ai";
 import type { ThinkingLevel } from "@earendil-works/pi-agent-core";
+import type { LhMessage } from "../native-messages.ts";
 import type { Phase3 } from "../phases.ts";
 import type { PlanNodeStatus, PlanTree } from "./plan.ts";
 import type { EmissionStats, UnderstandingLevel } from "./graph.ts";
 
 // ─── Chat records (the session store's on-disk format) ───────────────────────
 
-/** One persisted session: data/chats/<id>.json. The stored messages are full
+/** One persisted session: data/chats/<id>.json. Wave B (owner-approved
- * AI SDK UIMessages (parts included) — the canonical session record: a
+ * 2026-09-26): the stored messages are pi-NATIVE history (LhMessage — the
- * pending quiz is a tool part in `input-available` state, which is exactly
+ * agent loop's own shapes, provider/model/usage/thinkingSignature stamped
- * what makes resume-mid-question free. */
+ * by pi) — the canonical session record IS the agent state; replay is
+ * `state.messages = record.messages` + continue(). The client-shaped view
+ * is the one-way projection (core/projection.ts) — a pending quiz is an
+ * unanswered question tool call, which is exactly what makes
+ * resume-mid-question free. */
 export interface ChatRecord {
 	id: string;
 	title: string;
 	createdAt: string;
 	updatedAt: string;
-	messages: UIMessage[];
+	messages: LhMessage[];
 	/** The session's plan tree (vision §2) — written by plan tools via saveTree. */
 	tree?: PlanTree;
 	/** Append-only usage log (observability, 2026-09): one entry per model
@@ -152,8 +157,8 @@ export interface TurnUsage {
  *  both verdicts are real transcript events: accept sanctions teaching,
  *  decline asks for revision. The part is the message TYPE (the "custom
  *  message" scheme, 2026-09-12): the message carries no human-authored text,
- *  the model-facing wording is owned by the adapter (record-adapter.ts
+ *  the model-facing wording is owned by toLlmMessages (native-messages.ts
- *  flattens it to VERDICT_TEXT below), and the UI renders the verdict
+ *  flattens it to verdictText below), and the UI renders the verdict
  *  marker — never a user bubble. A learner who also typed a note sends the
  *  note as its own real user message first; the verdict message follows. */
 export interface PlanVerdictData {

src/core/contracts/jobs.ts

@@ -6,8 +6,9 @@
  * master. Pure types + protocol docs + tiny pure helpers; type-only imports
  * of "ai" (safe everywhere: server, client, tests). See docs/vision.md.
  */
-import type { UIMessage } from "ai";
 import type { CallUsage } from "./chat.ts";
+import type { LhMessage, LhMarkerMessage } from "../native-messages.ts";
+import { newHandoffMessage } from "../native-messages.ts";
 
 // ─── Async sub-agent jobs (vision §2.5; plan.md Wave 0 protocol) ────────────
 
@@ -141,7 +142,7 @@ export function accumulateJobUsage(
  *
  *  3. On completion the runner builds a STEER MESSAGE (buildSubagentSteer)
  *     and hands it to the wake pipeline (src/server/jobs.ts): a user-role
- *     UIMessage carrying the result — a text part with what the MODEL needs
+ *     result-carrying native marker — the content is what the MODEL needs
  *     (the research brief, the builder's notes), plus a data-subagent-artifact
  *     part with what the UI renders (the full result: brief + sources /
  *     SVG / demo HTML). Provider conversion drops data parts, so artifact
@@ -245,6 +246,14 @@ export interface PdfResult {
 }
 
 // ─── Sub-agent steer messages (THE ASYNC PROTOCOL §3–4) ─────────────────────
+//
+// Wave B (owner-approved 2026-09-26): steers are NATIVE record messages —
+// LhMarkerMessage customs (role "custom"), the custom-message taxonomy's
+// wake members. The model-facing text rides `content` (single-sourced
+// below); the UI payload (the artifact, the abort badge) rides `details`
+// and never reaches the model (toLlmMessages maps the marker to a user
+// message carrying `content` only). The deterministic id (`steer_<jobId>`)
+// IS the idempotency key — steerDelivered matches on it.
 
 /** Message metadata marking a sub-agent steer (contracts.ts §3). */
 export interface SubagentResultMeta {
@@ -264,40 +273,14 @@ export interface SubagentArtifactData {
 	result: ResearchResult | DemoResult | VisualResult | PdfResult;
 }
 
-/**
+/** A result steer's marker details: the UI's meta + artifact in one
- * The steer message: user-role on the wire (UIMessage roles are fixed), but
+ *  payload (the projection splits it into metadata + data part). */
- * NEVER a learner interjection — metadata.subagentResult is the marker the
+export interface SteerDetails extends SubagentResultMeta {
- * UI branches on, and the artifact rides the data part (stripped by provider
+	result: ResearchResult | DemoResult | VisualResult | PdfResult;
- * conversion, so the model sees only the text part).
- */
-export interface SubagentSteerMessage extends UIMessage {
-	role: "user";
-	metadata: { subagentResult: SubagentResultMeta };
-	parts: [
-		{ type: "text"; text: string },
-		{ type: "data-subagent-artifact"; data: SubagentArtifactData },
-	];
 }
 
-/** The abort steer: user-role like any steer, but NO artifact part —
+/** Anything the wake pipeline may queue and deliver — a native marker. */
- * there is no result to render, only the teacher-facing text. Shares the
+export type SteerMessage = LhMarkerMessage;
- * result steer's deterministic id space (`steer_${jobId}`): steerDelivered
- * matches on metadata jobId, so an abort and a (racing) result steer
- * can never BOTH deliver — exactly one wakes the teacher. */
-export interface AbortSteerMessage extends UIMessage {
-	role: "user";
-	metadata: { subagentResult: SubagentResultMeta & { aborted: true } };
-	parts: [
-		{ type: "text"; text: string },
-		{ type: "data-subagent-aborted"; data: SubagentResultMeta & { aborted: true } },
-	];
-}
-
-/** Anything the wake pipeline may queue and deliver. */
-export type SteerMessage =
-	| SubagentSteerMessage
-	| AbortSteerMessage
-	| ProbeHandoffSteerMessage;
 
 /** Whether a result is the failure shape (html/svg empty, failure brief). */
 export function isSubagentFailure(
@@ -354,35 +337,38 @@ function steerText(kind: JobKind, result: ResearchResult | DemoResult | VisualRe
 export function buildSubagentSteer(
 	job: Pick<JobRecord, "id" | "kind" | "toolCallId">,
 	result: ResearchResult | DemoResult | VisualResult | PdfResult,
-): SubagentSteerMessage {
+): SteerMessage {
 	return {
 		id: `steer_${job.id}`,
-		role: "user",
+		role: "custom",
-		metadata: { subagentResult: { jobId: job.id, kind: job.kind, toolCallId: job.toolCallId } },
+		customType: "subagent-steer",
-		parts: [
+		content: steerText(job.kind, result),
-			{ type: "text", text: steerText(job.kind, result) },
+		display: true,
-			{ type: "data-subagent-artifact", data: { kind: job.kind, result } },
+		details: {
-		],
+			jobId: job.id,
+			kind: job.kind,
+			toolCallId: job.toolCallId,
+			result,
+		},
+		timestamp: Date.now(),
 	};
 }
 
 /** Build the abort steer for an aborted job (pure — shared by the
  * abort path in src/server/jobs.ts and tests). Same id space as the result
- * steer; see AbortSteerMessage. */
+ * steer (same id space — exactly one delivers). */
 export function buildAbortSteer(
 	job: Pick<JobRecord, "id" | "kind" | "toolCallId">,
-): AbortSteerMessage {
+): SteerMessage {
 	const meta = { jobId: job.id, kind: job.kind, toolCallId: job.toolCallId, aborted: true } as const;
 	return {
 		id: `steer_${job.id}`,
-		role: "user",
+		role: "custom",
-		metadata: { subagentResult: meta },
+		customType: "subagent-abort",
-		parts: [
+		content: abortText(job.kind),
-			{ type: "text", text: abortText(job.kind) },
+		display: true,
-			// The message-type marker (the custom-message scheme): the UI
+		details: meta,
-			// renders the abort badge off this part, not off metadata.
+		timestamp: Date.now(),
-			{ type: "data-subagent-aborted", data: meta },
-		],
 	};
 }
 
@@ -403,34 +389,19 @@ function abortText(kind: JobKind): string {
 // probe_done's execute queues this through the same wake pipeline; the
 // pump fires it once the prober's turn ends (gates + grace). It carries no
 // artifact — the assessment it references is durable in the transcript as
-// the probe_done tool part. Deterministic id per chat: exactly one
+// the probe_done tool result. Deterministic id per chat: exactly one
-// handoff, idempotent re-delivery.
+// handoff, idempotent re-delivery. The marker's content is HANDOFF_TEXT
+// (core/contracts/chat.ts — single source); the UI renders the quiet
+// system line off the customType. Nothing human-looking is persisted, ever.
 
-export interface ProbeHandoffSteerMessage extends UIMessage {
+export function buildProbeHandoffSteer(chatId: string): SteerMessage {
-	id: `steer_probe_${string}`;
+	return newHandoffMessage(chatId);
-	role: "user";
-	metadata: { probeHandoff: { chatId: string } };
-	/** The custom-message scheme (2026-09-12): NO text part — the wake is
-	 *  scaffolding, not speech. The model-facing instruction is owned by the
-	 *  adapter (record-adapter.ts flattens this part to HANDOFF_TEXT in
-	 *  core/contracts/chat.ts); the UI renders the quiet system line off the
-	 *  part. Nothing human-looking is persisted, ever. */
-	parts: [{ type: "data-probe-handoff"; data: { chatId: string } }];
-}
-
-export function buildProbeHandoffSteer(chatId: string): ProbeHandoffSteerMessage {
-	return {
-		id: `steer_probe_${chatId}`,
-		role: "user",
-		metadata: { probeHandoff: { chatId } },
-		parts: [{ type: "data-probe-handoff", data: { chatId } }],
-	};
 }
 
 /** True when the transcript already carries this steer — idempotent
  *  delivery for ANY steer kind: every steer id is deterministic per its
  *  event (steer_<jobId> for jobs, steer_probe_<chatId> for the handoff). */
-export function steerDelivered(messages: UIMessage[], steerId: string): boolean {
+export function steerDelivered(messages: LhMessage[], steerId: string): boolean {
 	return messages.some((m) => m.id === steerId);
 }
 

src/core/index.ts

@@ -32,6 +32,12 @@ export * from "./pending.ts";
 export * from "./prompt-segments.ts";
 export * from "./math-delims.ts";
 export * from "./ui-message.ts";
+// Wave B (owner-approved 2026-09-26): the native record (LhMessage), the
+// one-way client-view projection, and the input-events contract — all
+// pure logic, browser-safe.
+export * from "./native-messages.ts";
+export * from "./projection.ts";
+export * from "./input-events.ts";
 export * from "./tool-parts.ts";
 export * from "./prices.ts";
 export * from "./cost-summary.ts";

src/core/input-events.ts

@@ -0,0 +1,121 @@
+/**
+ * THE INPUT-EVENTS CONTRACT (Wave B, owner ruling 2026-09-26: "input
+ * events now, in the same pass"): POST /api/chat carries `{chatId, input}`
+ * — ONE explicit event, never a client transcript. The server owns the
+ * record; a send tells it what HAPPENED, not what the client's list looks
+ * like. The 409 merge-retry died with the full-list body (an input event
+ * retries idempotently: nothing was appended when a POST is refused).
+ *
+ * The four events (the complete client-originated input taxonomy):
+ *   text    — a learner-authored user message (composer send, initial
+ *             topic, the demo error-fix loop)
+ *   answer  — the pending question's graded result (QuestionAnswerData,
+ *             built client-side exactly as today; a dismissal is an answer
+ *             carrying its flag). Server-side this becomes the call's
+ *             native tool result — fork 1's normal agent history.
+ *   verdict — the plan verdict (accept/decline); an optional note is the
+ *             learner's own real user message, sent first, exactly the
+ *             two-real-messages scheme.
+ *   continue — run the next turn on the current record (mount
+ *             continuations, job-settle re-syncs: the record ends at an
+ *             answered question with no teacher reaction yet).
+ *
+ * Server-originated delivery (the wake pipeline's steers) is NOT a client
+ * input — the handler accepts it on the same path (TurnInput) so every
+ * turn rides one composition.
+ */
+
+import type { QuestionAnswerData } from "./question-core.ts";
+import type { LhMessage } from "./native-messages.ts";
+import {
+	danglingQuestionOf,
+	newAnswerResult,
+	newUserMessage,
+	newVerdictMessage,
+} from "./native-messages.ts";
+import { QUESTION_TOOLS } from "./pending.ts";
+
+/** One client-originated input event (the POST body's `input`). */
+export type ChatInput =
+	| { type: "text"; text: string }
+	| { type: "answer"; toolCallId: string; answer: QuestionAnswerData }
+	| { type: "verdict"; accepted: boolean; note?: string }
+	| { type: "continue" };
+
+/** A wake-pipeline steer delivery — same turn composition, server-origin. */
+export type SteerInput = { type: "steer"; steer: LhMessage };
+
+/** Every input the turn composition accepts. */
+export type TurnInput = ChatInput | SteerInput;
+
+/** A malformed input event (the honest 400 — the orphan-trap discipline). */
+export class ChatInputError extends Error {}
+
+/** Parse and validate an input event off a request body. */
+export function parseChatInput(input: unknown): ChatInput {
+	if (typeof input !== "object" || input === null) throw new ChatInputError("input must be an object");
+	const i = input as Record<string, unknown>;
+	switch (i.type) {
+		case "text":
+			if (typeof i.text !== "string" || (i.text as string).trim().length === 0) {
+				throw new ChatInputError("text input requires non-empty text");
+			}
+			return { type: "text", text: i.text };
+		case "answer":
+			if (typeof i.toolCallId !== "string" || i.toolCallId.length === 0) {
+				throw new ChatInputError("answer input requires toolCallId");
+			}
+			if (typeof i.answer !== "object" || i.answer === null) {
+				throw new ChatInputError("answer input requires the graded answer object");
+			}
+			return { type: "answer", toolCallId: i.toolCallId, answer: i.answer as QuestionAnswerData };
+		case "verdict":
+			if (typeof i.accepted !== "boolean") throw new ChatInputError("verdict input requires accepted");
+			if (i.note !== undefined && typeof i.note !== "string") {
+				throw new ChatInputError("verdict note must be a string");
+			}
+			return { type: "verdict", accepted: i.accepted, note: i.note as string | undefined };
+		case "continue":
+			return { type: "continue" };
+		default:
+			throw new ChatInputError(`unknown input type: ${String(i.type)}`);
+	}
+}
+
+/**
+ * The native appends an input event makes to the record (pure). The caller
+ * persists them write-ahead; the agent's context is the record plus these.
+ *
+ * Answer validation is the orphan-400 discipline: the call must be a
+ * DANGLING QUESTION call in the record (posed, never answered) — anything
+ * else 400s honestly instead of silently interrupting a question or
+ * double-answering.
+ */
+export function inputAppends(record: { messages: LhMessage[] }, input: ChatInput): LhMessage[] {
+	switch (input.type) {
+		case "text":
+			return [newUserMessage(input.text)];
+		case "answer": {
+			const pending = danglingQuestionOf(record.messages);
+			if (!pending || pending.toolCallId !== input.toolCallId) {
+				throw new ChatInputError("answer input targets no pending question call");
+			}
+			return [newAnswerResult(input.toolCallId, pending.tool, input.answer)];
+		}
+		case "verdict": {
+			const appends: LhMessage[] = [];
+			if (input.note && input.note.trim().length > 0) {
+				appends.push(newUserMessage(input.note));
+			}
+			appends.push(newVerdictMessage(input.accepted, new Date().toISOString()));
+			return appends;
+		}
+		case "continue":
+			return [];
+	}
+}
+
+/** Is this tool name a question tool (dock-owned, answer-gated)? */
+export function isQuestionTool(name: string): boolean {
+	return (QUESTION_TOOLS as readonly string[]).includes(name);
+}

src/core/native-messages.ts

@@ -0,0 +1,284 @@
+/**
+ * THE NATIVE MESSAGE RECORD (Wave B, owner-approved 2026-09-26): chat
+ * records store pi's own message shapes — the exact history the agent
+ * loop builds — instead of AI-SDK UIMessages. Provider, model, usage,
+ * stopReason, and thinking signatures are stamped by pi itself; replay is
+ * `state.messages = record.messages` + `continue()` — the record IS the
+ * agent state.
+ *
+ * WHY pi MESSAGES LACK OUR `id`: pi's session format gives every ENTRY an
+ * id, never the message. This app needs a per-message id for client
+ * identity (React keys, append-only adoption, the continuation seam), so
+ * every record message carries ONE extra field — `id` — alongside the
+ * native shape. `toLlmMessages` strips it at the wire: the provider never
+ * sees it (verified single site, below).
+ *
+ * UI-ONLY CONTENT (owner ruling, fork 1 + the plan's custom-message
+ * taxonomy): verdict markers, the probe→teach handoff, sub-agent steers,
+ * and plan blocks are LhMarkerMessage — this app's declaration-merged
+ * member of pi-agent-core's CustomAgentMessages extension point, shaped
+ * exactly like pi's own CustomMessage ({role:"custom", customType,
+ * content, display, details}). ONE seam — toLlmMessages, wired as the
+ * agent's convertToLlm — owns every model-facing decision: markers
+ * flatten to their canonical user text (single-sourced in
+ * core/contracts), plan blocks are UI-only and filtered, and dangling
+ * tool calls (an aborted turn) get the interrupted-result synthesis the
+ * provider protocol demands.
+ *
+ * Answers (fork 1, owner 2026-09-26): the learner's answer IS the tool
+ * call's ToolResultMessage — appended natively at answer time. The
+ * synthetic "question posed" placeholder is an in-memory loop device
+ * (Wave A's terminate) and is never persisted: the record ends at the
+ * unanswered call in the pose→answer window, where no turn can run (the
+ * question gate holds steers; a POST would 409).
+ */
+
+import type { AgentMessage } from "@earendil-works/pi-agent-core";
+import type { AssistantMessage, Message, ToolResultMessage, UserMessage } from "@earendil-works/pi-ai";
+import { QUESTION_TOOLS } from "./pending.ts";
+import { HANDOFF_TEXT, verdictText } from "./contracts/chat.ts";
+
+/** The hard-invariant wording for an aborted turn's unanswered calls —
+ *  carried over verbatim from the pre-native era so the model's view
+ *  never drifted. */
+export const INTERRUPTED_TEXT =
+	"The question was interrupted — the learner never answered; continue without holding a result for it.";
+
+// ─── The record's message type ───────────────────────────────────────────────
+
+/**
+ * The app's custom message (declaration-merged into pi-agent-core's
+ * CustomAgentMessages below). Shaped like pi's own CustomMessage —
+ * `content` is the MODEL-facing text (single-sourced in core/contracts,
+ * never fake human speech), `details` is the UI payload (never
+ * model-visible), `display` marks messages the UI renders (our projection
+ * keys rendering on customType; the flag documents intent).
+ */
+export interface LhMarkerMessage {
+	/** Record identity (pi messages carry no id — see the file header). */
+	id: string;
+	role: "custom";
+	customType: "verdict" | "probe-handoff" | "subagent-steer" | "subagent-abort" | "plan-block";
+	/** The model-facing text ("" for plan blocks — UI-only). */
+	content: string;
+	display: boolean;
+	/** The UI payload — per-customType, never model-visible. */
+	details: unknown;
+	timestamp: number;
+}
+
+declare module "@earendil-works/pi-agent-core" {
+	interface CustomAgentMessages {
+		lhMarker: LhMarkerMessage;
+	}
+}
+
+/** A record message: a native pi message (or our marker) plus the record id. */
+export type LhMessage = (UserMessage | AssistantMessage | ToolResultMessage | LhMarkerMessage) & { id: string };
+
+/** A record message list is assignable to the agent's context — that IS
+ *  the replay (ui-stream/chat-handler assign it to initialState.messages). */
+export function asAgentMessages(messages: readonly LhMessage[]): AgentMessage[] {
+	return messages as unknown as AgentMessage[];
+}
+
+// ─── id minting ──────────────────────────────────────────────────────────────
+
+/** The app-wide message id shape (same as the UIMessage-era mint). */
+export function newMessageId(): string {
+	return `msg_${Date.now().toString(36)}_${crypto.randomUUID().slice(0, 8)}`;
+}
+
+// ─── constructors (the input-event → native append mapping lives in
+//     core/input-events.ts; steers in core/contracts/jobs.ts) ─────────────────
+
+/** A learner-authored user message (text input, verdict note). */
+export function newUserMessage(text: string): LhMessage & UserMessage {
+	return {
+		id: newMessageId(),
+		role: "user",
+		content: text,
+		timestamp: Date.now(),
+	};
+}
+
+/** The learner's answer — the question call's tool result (fork 1).
+ *  `answer` is the structured QuestionAnswerData the client graded; the
+ *  MODEL sees its JSON encoding (the pre-native wire shape),
+ *  the UI sees the structured payload via `details`. */
+export function newAnswerResult(
+	toolCallId: string,
+	toolName: string,
+	answer: unknown,
+): LhMessage & ToolResultMessage {
+	return {
+		id: newMessageId(),
+		role: "toolResult",
+		toolCallId,
+		toolName,
+		content: [{ type: "text", text: JSON.stringify(answer) }],
+		details: answer,
+		isError: false,
+		timestamp: Date.now(),
+	};
+}
+
+/** The plan verdict (the plan→teach seam): marker only — the model-facing
+ *  wording is owned by verdictText (core/contracts/chat.ts), the UI
+ *  renders the quiet accept/decline line off details. */
+export function newVerdictMessage(accepted: boolean, at: string): LhMarkerMessage {
+	return {
+		id: newMessageId(),
+		role: "custom",
+		customType: "verdict",
+		content: verdictText(accepted),
+		display: true,
+		details: { accepted, at },
+		timestamp: Date.now(),
+	};
+}
+
+/** The probe→teach handoff wake: scaffolding, not speech — the model reads
+ *  HANDOFF_TEXT, the UI renders the quiet system line. */
+export function newHandoffMessage(chatId: string): LhMarkerMessage {
+	return {
+		id: `steer_probe_${chatId}`,
+		role: "custom",
+		customType: "probe-handoff",
+		content: HANDOFF_TEXT,
+		display: true,
+		details: { chatId },
+		timestamp: Date.now(),
+	};
+}
+
+/** The plan presentation block: pure UI history (a frozen snapshot), no
+ *  model face — toLlmMessages filters it. `planCallId` keys idempotent
+ *  emission (one block per successful plan_init call). */
+export function newPlanBlockMessage(
+	planCallId: string,
+	block: unknown,
+): LhMarkerMessage {
+	return {
+		id: `pb_${Date.now().toString(36)}_${crypto.randomUUID().slice(0, 8)}`,
+		role: "custom",
+		customType: "plan-block",
+		content: "",
+		display: true,
+		details: { planCallId, block },
+		timestamp: Date.now(),
+	};
+}
+
+// ─── the one model-facing seam (the agent's convertToLlm) ────────────────────
+
+/** The ids of every toolResult in the tail (for the dangling-call scan). */
+function resultIdsFrom(messages: readonly AgentMessage[]): Set<string> {
+	const ids = new Set<string>();
+	for (const m of messages) {
+		if ((m as { role?: string }).role === "toolResult") {
+			ids.add((m as ToolResultMessage).toolCallId);
+		}
+	}
+	return ids;
+}
+
+/**
+ * AgentMessage[] → the provider wire (the agent's convertToLlm — required
+ * by pi-agent-core's loop config, the ONE place model-facing decisions
+ * live):
+ *
+ * - user / assistant / toolResult pass through VERBATIM — signatures,
+ *   usage, provider stamps all native — minus our record-`id` field.
+ * - markers flatten to a user message carrying their content (the
+ *   canonical text single-sourced in core/contracts); plan blocks are
+ *   UI-only and filtered.
+ * - dangling tool calls (an aborted turn's unanswered questions) get the
+ *   synthesized interrupted result — the provider protocol's hard
+ *   invariant: a tool call must be followed by its result.
+ *
+ * Contract (pi-agent-core): never throws — an unknown shape passes
+ * through untouched rather than killing the loop.
+ */
+export function toLlmMessages(messages: readonly AgentMessage[]): Message[] {
+	const out: Message[] = [];
+	for (let i = 0; i < messages.length; i++) {
+		const m = messages[i]!;
+		const role = (m as { role?: string }).role;
+		if (role === "custom") {
+			const marker = m as LhMarkerMessage;
+			if (marker.customType === "plan-block") continue; // UI-only
+			out.push({
+				role: "user",
+				content: [{ type: "text", text: marker.content }],
+				timestamp: marker.timestamp,
+			});
+			continue;
+		}
+		// Strip the record id: the wire carries the native shape only.
+		const { id: _id, ...native } = m as LhMessage;
+		out.push(native as Message);
+		// Dangling-call synthesis: an assistant message whose toolCalls have
+		// no results in the remaining tail (abort mid-question) — the
+		// provider rejects unanswered calls outright.
+		if (role === "assistant") {
+			const assistant = m as AssistantMessage;
+			const calls = assistant.content.filter((b) => b.type === "toolCall");
+			if (calls.length === 0) continue;
+			const answered = resultIdsFrom(messages.slice(i + 1));
+			for (const call of calls) {
+				if (answered.has(call.id)) continue;
+				out.push({
+					role: "toolResult",
+					toolCallId: call.id,
+					toolName: call.name,
+					content: [{ type: "text", text: INTERRUPTED_TEXT }],
+					isError: false,
+					timestamp: assistant.timestamp,
+				});
+			}
+		}
+	}
+	return out;
+}
+
+// ─── native scans (the UIMessage-era pending/phase seams, natively) ──────────
+
+/** The pending-question gate (findPendingToolCall's native twin): the
+ *  NEWEST assistant message's FIRST question-tool call with no result in
+ *  the tail — one question at a time, the dock's subject. */
+export function danglingQuestionOf(
+	messages: readonly LhMessage[],
+): { toolCallId: string; tool: string; input: unknown } | null {
+	for (let mi = messages.length - 1; mi >= 0; mi--) {
+		const m = messages[mi]!;
+		if ((m as { role?: string }).role !== "assistant") continue;
+		const assistant = m as AssistantMessage & { id: string };
+		const answered = resultIdsFrom(messages.slice(mi + 1));
+		for (const block of assistant.content) {
+			if (block.type !== "toolCall") continue;
+			if (!(QUESTION_TOOLS as readonly string[]).includes(block.name)) continue;
+			if (answered.has(block.id)) continue;
+			return { toolCallId: block.id, tool: block.name, input: block.arguments };
+		}
+		return null; // the newest assistant message's questions are all answered
+	}
+	return null;
+}
+
+/** The probe→teach construction seam (chat-handler): a probe_done call in
+ *  the transcript — any state — means the probe is concluded: teach. */
+export function hasProbeDone(messages: readonly LhMessage[]): boolean {
+	for (const m of messages) {
+		if ((m as { role?: string }).role !== "assistant") continue;
+		const assistant = m as AssistantMessage;
+		if (assistant.content.some((b) => b.type === "toolCall" && b.name === "probe_done")) return true;
+	}
+	return false;
+}
+
+/** Every toolResult id in the record — answer-event validation (the call
+ *  must be a DANGLING question call, not an already-answered one). */
+export function answeredCallIds(messages: readonly LhMessage[]): Set<string> {
+	return resultIdsFrom(messages);
+}

src/core/plan-blocks.ts

@@ -1,44 +1,38 @@
 /**
  * Plan-block emission (docs/probe-teach-split.md §6): the INTERIM plan
- * presentation seam. The plan renders IN FLOW once, at authoring — a full
+ * presentation seam. The plan renders IN FLOW once, at authoring — a
- * `data-plan-block` attached to the assistant message that carries the
+ * frozen snapshot attached right after the assistant group carrying the
  * successful plan_init call. It is the presentation moment for the plan
  * (and the popup's entry point) — statuses on it are accurate at that
- * instant (current = null, everything upcoming — unless the authoring is a
+ * instant (current = null, everything upcoming — unless the authoring is
- * mid-lesson rewrite, in which case the snapshot shows what was true then).
+ * a mid-lesson rewrite, in which case the snapshot shows what was true
+ * then).
  *
- * The neighborhood-block machinery (frozen fragments on plan movement) is
+ * Wave B (owner-approved 2026-09-26): the block is a native plan-block
- * RETIRED: position derives live from the transcript (derivePlanStatuses —
+ * MARKER appended at the turn's persist (idempotent per plan_init call);
- * calls, not results), and frozen snapshots can't represent live movement.
+ * the projection splices its data part into the assistant group IN FLOW,
- * The persistent DAG window (the UI wave) is the successor — always
+ * exactly where the UIMessage-era attach put it. The neighborhood-block
- * present, auto-moving with the lesson.
+ * machinery stays retired: position derives live from the transcript.
- *
- * Idempotent by construction: a message that already carries a plan-block
- * part is never given another (persist replays / retry paths are safe).
  */
 
 import type { PlanBlockData, PlanTree } from "./contracts.ts";
 import { derivePlanStatuses } from "./contracts.ts";
 import type { UIMessage } from "ai";
+import type { LhMessage } from "./native-messages.ts";
+import { newPlanBlockMessage } from "./native-messages.ts";
+import type { ToolResultMessage } from "@earendil-works/pi-ai";
 
 /** The message part the chat renderer consumes (TeacherUIDataParts key
- *  "plan-block" — the SDK strips the `data-` prefix from the name). */
+ *  "plan-block" — the SDK strips the `data-` prefix). Kept for the client
+ *  renderers; the projection emits this shape. */
 export interface PlanBlockPart {
 	type: "data-plan-block";
 	id: string;
 	data: PlanBlockData;
 }
 
-/** Does this message carry a successful plan_init (the trigger)? */
+/** The snapshot payload (unchanged since wave 4): statuses derived AT
-function hasSuccessfulPlanInit(message: UIMessage): boolean {
+ *  EMISSION time from the transcript — the block never re-derives. */
-	for (const part of message.parts) {
-		if (part.type !== "tool-plan_init") continue;
-		const ok = (part as { output?: { ok?: unknown } }).output?.ok;
-		if (ok === true) return true;
-	}
-	return false;
-}
-
 function snapshot(tree: PlanTree, messages: readonly UIMessage[]): PlanBlockData {
 	const statuses = derivePlanStatuses(tree, messages);
 	return {
@@ -54,36 +48,47 @@ function snapshot(tree: PlanTree, messages: readonly UIMessage[]): PlanBlockData
 	};
 }
 
-/**
+/** The record's plan-block markers, keyed by the plan_init call they
- * Enrich a message list with plan-presentation blocks — THE emission
+ *  present — the idempotency set for emission. */
- * seam's pure half. `messages` is the deduped list persistTurn is about to
+export function emittedPlanBlockCalls(messages: readonly LhMessage[]): Set<string> {
- * write; `tree` is the record's current tree (the plan tool saved it during
+	const out = new Set<string>();
- * the turn). Messages already carrying a block are never touched.
+	for (const m of messages) {
- */
+		if ((m as { role?: string }).role !== "custom") continue;
-export function withPlanBlocks(messages: UIMessage[], tree: PlanTree | null | undefined): UIMessage[] {
+		const marker = m as { customType?: string; details?: { planCallId?: unknown } };
-	if (!tree || tree.nodes.length === 0 || messages.length === 0) return messages;
+		if (marker.customType === "plan-block" && typeof marker.details?.planCallId === "string") {
-	const blockId = `pb_${Date.now().toString(36)}_${crypto.randomUUID().slice(0, 8)}`;
+			out.add(marker.details.planCallId);
-	return messages.map((m) => {
+		}
-		if (m.role !== "assistant" || m.parts.some((p) => p.type === "data-plan-block")) return m;
+	}
-		if (!hasSuccessfulPlanInit(m)) return m;
+	return out;
-		// POSITION, not append: emission runs at persistTurn — after the whole
-		// turn is composed — so appending would bury the block under every
-		// teaching note and quiz of the same turn. The block renders IN FLOW
-		// immediately after the plan_init call it presents (after the LAST
-		// one if a turn carried multiple — a rewrite).
-		const idx = lastIndexOfSuccessfulPlanInit(m.parts);
-		const parts = m.parts.slice();
-		parts.splice(idx + 1, 0, { type: "data-plan-block", id: blockId, data: snapshot(tree, messages) } satisfies PlanBlockPart);
-		return { ...m, parts };
-	});
 }
 
-/** Index of the last tool-plan_init part with an ok output in this message. */
+/**
-function lastIndexOfSuccessfulPlanInit(parts: ReadonlyArray<{ type: string }>): number {
+ * The native emission seam (pure): ONE plan-block marker per TURN — for
-	let idx = -1;
+ *  the turn's LAST successful plan_init call (a same-turn rewrite presents
-	parts.forEach((p, i) => {
+ *  once; a later turn's rewrite gets its own block — the golden-master
-		if (p.type !== "tool-plan_init") return;
+ *  rule the UIMessage-era attach had) that the record hasn't already
-		if ((p as { output?: { ok?: unknown } }).output?.ok === true) idx = i;
+ *  emitted. `tree` is the record's current tree (the plan tool saved it
-	});
+ *  during the turn); `transcript` is the full PROJECTED transcript the
-	return idx;
+ *  status derivation reads.
+ */
+export function planBlocksFor(
+	record: readonly LhMessage[],
+	newMessages: readonly LhMessage[],
+	tree: PlanTree | null | undefined,
+	transcript: readonly UIMessage[],
+): LhMessage[] {
+	if (!tree || tree.nodes.length === 0) return [];
+	const emitted = emittedPlanBlockCalls(record);
+	let last: { toolCallId: string } | null = null;
+	for (const m of newMessages) {
+		if ((m as { role?: string }).role !== "toolResult") continue;
+		const result = m as ToolResultMessage & { id: string };
+		if (result.toolName !== "plan_init") continue;
+		const ok = (result.details as { ok?: unknown } | undefined)?.ok;
+		if (ok !== true) continue;
+		if (emitted.has(result.toolCallId)) continue;
+		last = { toolCallId: result.toolCallId };
+	}
+	if (!last) return [];
+	return [newPlanBlockMessage(last.toolCallId, snapshot(tree, transcript))];
 }

src/core/ports.ts

@@ -9,7 +9,7 @@
  * adapters may import core; core NEVER imports an adapter.
  */
 
-import type { UIMessage } from "ai";
+import type { LhMessage } from "./native-messages.ts";
 import type {
 	ChatRecord,
 	ChatSettings,
@@ -39,8 +39,9 @@ export interface ChatStore {
 	getChat(id: string): ChatRecord | null;
 	/** All sessions, newest activity first (the sidebar's list view). */
 	listChats(): ChatSummary[];
-	/** Persist the full message list (client state + new response) after a turn. */
+	/** Persist the full native message list (the record IS the agent
-	saveMessages(id: string, messages: UIMessage[]): void;
+	 * state — Wave B, owner-approved 2026-09-26). */
+	saveMessages(id: string, messages: LhMessage[]): void;
 	/** Persist the session plan tree (plan tools call this in execute). */
 	saveTree(id: string, tree: PlanTree): void;
 	/** Append one usage entry to the record's turn log (the money channel,

src/core/projection.ts

@@ -0,0 +1,199 @@
+/**
+ * THE ONE-WAY PROJECTION (Wave B, owner-approved 2026-09-26): native record
+ * messages → AI-SDK UIMessages. The record is pi-native history; every
+ * existing consumer — GET /api/chats/[id], the client's renderer, phase/
+ * pending/coverage/extraction scanners — reads THIS projection until Wave
+ * D replaces the client dialect. One direction only: nothing ever converts
+ * UIMessages back into native messages (the lossy record-adapter direction
+ * is deleted wholesale).
+ *
+ * GROUPING RULE (the golden master): a turn's UIMessage shape is one
+ * assistant message per GROUP — consecutive assistant + toolResult
+ * messages, bounded by user/marker messages; toolResults attach to the
+ * tool part of their call (searching backward — an answered quiz's result
+ * lands on the part that asked it, even turns later); a group's id is its
+ * FIRST assistant message's id. This reproduces the client's live view
+ * exactly: the continuation merge (start-chunk id = the group's id) and
+ * the settled record converge to the same shape, so the settle sync never
+ * re-renders what streamed.
+ *
+ * Plan blocks (plan-blocks.ts's splice, moved here): a plan-block marker
+ * has no message of its own — its data part splices into the preceding
+ * assistant group, IN FLOW right after the last successful plan_init call
+ * (the presentation moment).
+ */
+
+import type { UIMessage } from "ai";
+import type { AssistantMessage, ToolResultMessage } from "@earendil-works/pi-ai";
+import type { LhMarkerMessage, LhMessage } from "./native-messages.ts";
+
+import type { SubagentArtifactData, SubagentResultMeta } from "./contracts/jobs.ts";
+import type { PlanBlockData, PlanVerdictData } from "./contracts/chat.ts";
+
+/** Loose part shapes the projection emits (the client's part shapes). */
+type Part = Record<string, unknown> & { type: string };
+type LooseMessage = { id: string; role: "user" | "assistant"; parts: Part[]; metadata?: unknown };
+
+function textPart(text: string): Part {
+	return { type: "text", text, state: "done" };
+}
+
+/** The result a tool part should show, from a native toolResult. */
+function applyResult(part: Part, result: ToolResultMessage): void {
+	if (result.isError) {
+		part.state = "output-error";
+		part.rawInput = part.input;
+		const text = result.content.find((c) => c.type === "text");
+		part.errorText = text && text.type === "text" ? text.text : "The tool call failed.";
+	} else {
+		part.state = "output-available";
+		part.output = result.details;
+	}
+}
+
+/** Does this assistant group carry a successful plan_init (the splice target)? */
+function lastSuccessfulPlanInit(parts: Part[]): number {
+	let idx = -1;
+	parts.forEach((p, i) => {
+		if (p.type !== "tool-plan_init") return;
+		const ok = (p.output as { ok?: unknown } | undefined)?.ok;
+		if (ok === true) idx = i;
+	});
+	return idx;
+}
+
+/** Project the native record into client-shaped UIMessages. Pure and
+ *  deterministic: the same record always projects to the same list. */
+export function projectNative(messages: readonly LhMessage[]): UIMessage[] {
+	const out: LooseMessage[] = [];
+
+	const lastAssistant = (): LooseMessage | undefined => {
+		const last = out[out.length - 1];
+		return last && last.role === "assistant" ? last : undefined;
+	};
+	const findToolPart = (toolCallId: string): Part | undefined => {
+		for (let i = out.length - 1; i >= 0; i--) {
+			for (const part of out[i]!.parts) {
+				if (part.type.startsWith("tool-") && part.toolCallId === toolCallId) return part;
+			}
+		}
+		return undefined;
+	};
+
+	for (const m of messages) {
+		const role = (m as { role?: string }).role;
+
+		if (role === "user") {
+			const content = m.content as string | Array<{ type: string; text?: string }>;
+			const texts = typeof content === "string" ? [content] : content.filter((c) => c.type === "text").map((c) => (c as { text: string }).text);
+			out.push({ id: m.id, role: "user", parts: texts.map(textPart) });
+			continue;
+		}
+
+		if (role === "custom") {
+			const marker = m as LhMarkerMessage;
+			projectMarker(marker, out);
+			continue;
+		}
+
+		if (role === "toolResult") {
+			const result = m as ToolResultMessage;
+			const part = findToolPart(result.toolCallId);
+			if (part) applyResult(part, result);
+			continue;
+		}
+
+		if (role === "assistant") {
+			const assistant = m as AssistantMessage;
+			const parts: Part[] = [];
+			let textN = 0;
+			let reasoningN = 0;
+			for (const block of assistant.content) {
+				if (block.type === "text") {
+					parts.push({ type: "text", id: `${m.id}-t${textN++}`, text: block.text, state: "done" });
+				} else if (block.type === "thinking") {
+					parts.push({ type: "reasoning", id: `${m.id}-r${reasoningN++}`, text: block.thinking, state: "done" });
+				} else if (block.type === "toolCall") {
+					parts.push({
+						type: `tool-${block.name}`,
+						toolCallId: block.id,
+						state: "input-available",
+						input: block.arguments,
+					});
+				}
+			}
+			if (parts.length === 0) continue; // presentation-only (nothing renderable)
+			const group = lastAssistant();
+			if (group) {
+				// Same group: the step separator renders between the steps.
+				group.parts.push({ type: "step-start" }, ...parts);
+			} else {
+				out.push({ id: m.id, role: "assistant", parts: [{ type: "step-start" }, ...parts] });
+			}
+			continue;
+		}
+	}
+
+	return out as unknown as UIMessage[];
+}
+
+/** A marker's projected message (verdict/handoff/steers) or splice (plan block). */
+function projectMarker(marker: LhMarkerMessage, out: LooseMessage[]): void {
+	switch (marker.customType) {
+		case "verdict": {
+			const data = marker.details as PlanVerdictData;
+			out.push({
+				id: marker.id,
+				role: "user",
+				parts: [{ type: "data-verdict", id: `vd_${marker.id}`, data }],
+			});
+			return;
+		}
+		case "probe-handoff": {
+			out.push({
+				id: marker.id,
+				role: "user",
+				parts: [{ type: "data-probe-handoff", id: `ph_${marker.id}`, data: marker.details }],
+			});
+			return;
+		}
+		case "subagent-steer": {
+			const meta = marker.details as SubagentResultMeta;
+			const artifact = marker.details as { kind: SubagentArtifactData["kind"]; result: SubagentArtifactData["result"] };
+			out.push({
+				id: marker.id,
+				role: "user",
+				metadata: { subagentResult: meta },
+				parts: [
+					textPart(marker.content),
+					{ type: "data-subagent-artifact", id: `sa_${marker.id}`, data: { kind: artifact.kind, result: artifact.result } },
+				],
+			});
+			return;
+		}
+		case "subagent-abort": {
+			const meta = marker.details as SubagentResultMeta & { aborted: true };
+			out.push({
+				id: marker.id,
+				role: "user",
+				metadata: { subagentResult: meta },
+				parts: [
+					textPart(marker.content),
+					{ type: "data-subagent-aborted", id: `sa_${marker.id}`, data: meta },
+				],
+			});
+			return;
+		}
+		case "plan-block": {
+			// No message of its own: splice into the preceding assistant
+			// group, IN FLOW after the last successful plan_init call.
+			const group = out[out.length - 1];
+			if (!group || group.role !== "assistant") return;
+			const idx = lastSuccessfulPlanInit(group.parts);
+			if (idx === -1) return;
+			const { block } = marker.details as { planCallId: string; block: PlanBlockData };
+			group.parts.splice(idx + 1, 0, { type: "data-plan-block", id: marker.id, data: block });
+			return;
+		}
+	}
+}

src/server/chat-handler.ts

@@ -1,4 +1,3 @@
-import type { UIMessage } from "ai";
 import type { Usage } from "@earendil-works/pi-ai";
 import { createProberAgent, createTeacherAgent, type AgentBuildOptions, type TeachingAgent } from "../agent/teacher-agent.ts";
 import { piEngineForSpec, type PiEngine } from "../agent/models.ts";
@@ -6,7 +5,6 @@ import { createJobRunner } from "../agent/subagents/runner.ts";
 import { createExtractionPipeline } from "../agent/subagents/extraction.ts";
 import type { ModelRole } from "../../config.ts";
 import { claimSteers, deliverJobResult, setJobRespawn, setTurnRunner } from "./jobs.ts";
-import { recordToPiMessages } from "./pi/record-adapter.ts";
 import { piTurnResponse, runPiTurn } from "./pi/ui-stream.ts";
 import { effectiveSettings, stores } from "./stores.ts";
 import { searchAvailable, searchProvider } from "./search.ts";
@@ -20,26 +18,35 @@ import {
 import { modelsNotConfigured, providerKeyMissing as providerKeyMissingEnvelope, type ProviderKeyMissing } from "../core/settings.ts";
 import { beginTurn, endTurn } from "./turn-liveness.ts";
 import { registerTurn, unregisterTurn } from "./turn-runs.ts";
-import { persistTurn, triggerExtraction, withMessageIds } from "./turn-service.ts";
+import { persistTurn, triggerExtraction } from "./turn-service.ts";
+import { hasProbeDone } from "../core/native-messages.ts";
+import { asAgentMessages } from "../core/native-messages.ts";
+import {
+	ChatInputError,
+	inputAppends,
+	parseChatInput,
+	type TurnInput,
+} from "../core/input-events.ts";
+import { steerDelivered } from "../core/contracts.ts";
 import type { CallUsage } from "../core/contracts.ts";
 
 /**
- * One chat turn: run the teaching agent over the client's message list and
+ * One chat turn over the server-owned native record. Framework-free (plain
- * stream the UI message stream back. Framework-free (plain Request/Response)
+ * Request/Response) so tests can drive it directly with a scripted faux
- * so tests can drive it directly with a scripted faux engine — the Next route
+ * engine — the Next route handler in app/api/chat is a one-line wrapper.
- * handler in app/api/chat is a one-line wrapper.
+ *
+ * THE INPUT-EVENTS CONTRACT (Wave B, owner ruling 2026-09-26): POST /api/chat
+ * carries {chatId, input} — one explicit event (text / answer / verdict /
+ * continue), never a client transcript. The server owns the record; this
+ * module is the TURN COMPOSITION ROOT: it turns the event into native
+ * record appends (core/input-events.ts), builds the agent from the record
+ * (the record IS the agent state — state.messages = record.messages,
+ * continue()), and runs the turn as a background object (pi/ui-stream.ts).
+ * Wake-pipeline steers ride the same composition (TurnInput's steer kind).
  *
- * This module is the TURN COMPOSITION ROOT: it wires the storage ports, the
- * job runner + wake pipeline, the teacher tools, and the turn services
- * (turn-service.ts) together — all actual work lives behind those seams.
  * THE SAME COMPOSITION serves both entry points: client requests and the
  * wake pipeline's server-side steers (src/server/jobs.ts) — one code path
  * for write-ahead persistence, turn liveness, and the turn services.
- *
- * Engine note (docs/pi-engine-swap.md): the agent is STATELESS per turn —
- * built fresh from the persisted record (recordToPiMessages), run by the
- * bridge (pi/ui-stream.ts), discarded at turn end. The record is the only
- * source of truth.
  */
 
 const jobRunner = createJobRunner({
@@ -82,18 +89,12 @@ export const extraction = createExtractionPipeline({
 		providerKeyPresent(provider) ? null : providerKeyMissingEnvelope(provider, [tier]),
 });
 
-
 // Wake-pipeline wiring (contracts.ts "THE ASYNC PROTOCOL" §4): the pipeline
-// fires its server-side teacher turns through THIS composition root, and
+// delivers its steers through THIS composition root (one event: the steer
-// crash recovery re-spawns orphaned sub-agent loops through THIS runner.
+// marker, appended natively under the turn claim), and crash recovery
-setTurnRunner(async (chatId, messages) => {
+// re-spawns orphaned sub-agent loops through THIS runner.
-	const res = await handleChatRequest(
+setTurnRunner(async (chatId, input) => {
-		new Request("http://localhost/api/chat", {
+	const res = await handleChatInput(chatId, input);
-			method: "POST",
-			headers: { "Content-Type": "application/json" },
-			body: JSON.stringify({ chatId, messages }),
-		}),
-	);
 	// Drive the stream to completion server-side — nobody else will read it,
 	// and onFinish (persist, extraction, endTurn) only runs when it drains.
 	await res.arrayBuffer().catch(() => undefined);
@@ -110,39 +111,44 @@ function resolveEngine(role: ModelRole): PiEngine | undefined {
 
 setJobRespawn((jobId) => void jobRunner.runJob(jobId));
 
-/** The message-shape gate the SDK's UIMessageValidator owned: a malformed
+/** The route-facing entry: parse {chatId, input} and run one turn. */
- *  body must fail BEFORE the stream exists — the path where no onFinish will
- *  ever run (the catch clears the turn registry so the chat never locks). */
-function assertValidUiMessages(messages: UIMessage[]): void {
-	for (const m of messages) {
-		if (m.role !== "user" && m.role !== "assistant" && m.role !== "system") {
-			throw new Error(`invalid message role: ${String((m as { role?: unknown }).role)}`);
-		}
-		if (!Array.isArray(m.parts)) throw new Error("message has no parts array");
-		for (const p of m.parts) {
-			if (p.type === "text" && typeof (p as { text?: unknown }).text !== "string") {
-				throw new Error("text part has no text");
-			}
-		}
-	}
-}
-
 export async function handleChatRequest(
 	req: Request,
-	buildAgent?: (outgoing: UIMessage[]) => TeachingAgent,
+	buildAgent?: (opts: AgentBuildOptions & { teaching: boolean }) => TeachingAgent,
 ): Promise<Response> {
-	let body: { chatId?: unknown; messages?: unknown };
+	let body: { chatId?: unknown; input?: unknown };
 	try {
 		body = await req.json();
 	} catch {
 		return Response.json({ error: "Invalid JSON body" }, { status: 400 });
 	}
 	const chatId = typeof body.chatId === "string" ? body.chatId : "";
-	if (!chatId || !stores.chatStore.getChat(chatId)) {
+	if (!chatId) return Response.json({ error: "Unknown chat" }, { status: 404 });
-		return Response.json({ error: "Unknown chat" }, { status: 404 });
+	let input: TurnInput;
+	try {
+		input = parseChatInput(body.input);
+	} catch (err) {
+		if (err instanceof ChatInputError) {
+			return Response.json({ error: err.message }, { status: 400 });
 		}
-	if (!Array.isArray(body.messages)) {
+		throw err;
-		return Response.json({ error: "messages must be an array" }, { status: 400 });
+	}
+	return handleChatInput(chatId, input, buildAgent);
+}
+
+/**
+ * The turn composition: one input event → native record appends → one
+ * agent turn as a background object. Also the wake pipeline's entry
+ * (TurnInput's steer kind appends the marker under the same claim).
+ */
+export async function handleChatInput(
+	chatId: string,
+	input: TurnInput,
+	buildAgent?: (opts: AgentBuildOptions & { teaching: boolean }) => TeachingAgent,
+): Promise<Response> {
+	const record = stores.chatStore.getChat(chatId);
+	if (!record) {
+		return Response.json({ error: "Unknown chat" }, { status: 404 });
 	}
 
 	// THE UNIVERSAL TURN GATE (BYOK, owner, 2026-09-22): a turn needs the
@@ -154,10 +160,7 @@ export async function handleChatRequest(
 	// write-ahead persist (nothing durable changes), and every downstream
 	// resolution (jobs/extraction gate per-need on their own tiers).
 	const effective = effectiveSettings();
-	const conversation = resolveConversationSpec(
+	const conversation = resolveConversationSpec(record.settings, effective.models.strong);
-		stores.chatStore.getChat(chatId)?.settings,
-		effective.models.strong,
-	);
 	if (!conversation) {
 		const envelope = modelsNotConfigured(["strong"]);
 		console.info(`[chat ${chatId}] turn refused — ${JSON.stringify(envelope)}`);
@@ -179,10 +182,27 @@ export async function handleChatRequest(
 		return Response.json(envelope, { status: 503 });
 	}
 
+	// The input's native appends (pure; the honest 400 for an answer with no
+	// pending question call). Computed BEFORE beginTurn so a refused input
+	// leaves no liveness effects; read against the CURRENT record.
+	let appends;
+	try {
+		appends =
+			input.type === "steer"
+				? steerDelivered(record.messages, input.steer.id)
+					? []
+					: [input.steer]
+				: inputAppends(record, input);
+	} catch (err) {
+		if (err instanceof ChatInputError) {
+			return Response.json({ error: err.message }, { status: 400 });
+		}
+		throw err;
+	}
+
 	// One turn per chat, ever. A second request while a turn runs means a
-	// stale/remounted client raced a live one — its message list is outdated,
+	// stale/remounted client raced a live one — letting it through would
-	// and letting it through would double-run the teacher and clobber the
+	// double-run the teacher and clobber the first turn's persist.
-	// first turn's persist (saveMessages is last-writer-wins).
 	if (!beginTurn(chatId)) {
 		console.info(`[chat ${chatId}] turn already in flight — request rejected`);
 		return Response.json({ error: "A turn is already running for this session" }, { status: 409 });
@@ -190,40 +210,27 @@ export async function handleChatRequest(
 
 	// CONTINUATION COALESCING (async protocol §4, the delivery-starvation fix):
 	// steers finished while a quiz chain held the wake gates ride THIS turn —
-	// appended after the learner's answer (conversion-safe: the answer carries
+	// appended after the learner's answer (conversion-safe: the answer is the
-	// its output). Claiming happens after beginTurn, so this turn owns the
+	// question call's tool result now). Claiming happens after beginTurn, so
-	// registry and the write-ahead persist below makes the claim durable.
+	// this turn owns the registry and the write-ahead persist below makes the
-	// The incoming body is passed too: a pump-fired wake turn ALREADY CARRIES
+	// claim durable. Steers already in the transcript (a wake raced in) are
-	// its steer, so claimSteers finalizes that entry instead of appending a
+	// finalized by the claim itself — the append filter keeps exactly one copy.
-	// second copy (duplicate-key bug, 2026-09-18).
+	const steers = claimSteers(chatId).filter((s) => !steerDelivered(record.messages, s.id));
-	const steers = claimSteers(chatId, body.messages as UIMessage[]);
-	const outgoing = (
-		steers.length > 0 ? [...(body.messages as UIMessage[]), ...steers] : body.messages
-	) as UIMessage[];
 
-	// THE SETTINGS VIEW (settings-storage wave, 2026-09-19): resolved fresh
+	// Write-ahead persistence: the input's native appends go on disk BEFORE
-	// per turn (the gate above owns the read) — graph gates, tool toggles,
+	// the turn starts — the learner's answer is durable the instant the
-	// and the record's chat defaults all read from ONE small file.
+	// request arrives, and any remount, second tab, or server crash reads
-
+	// truth instead of the pre-answer record.
-	// Write-ahead persistence: the request body IS the client's canonical
+	const merged = [...record.messages, ...appends, ...steers];
-	// state, so it goes on disk BEFORE the stream starts. The learner's answer
-	// is durable the instant the request arrives — any remount, second tab, or
-	// server crash sees truth instead of the pre-answer record. (A client that
-	// returns mid-turn reads turnInFlight from the registry and re-attaches by
-	// polling instead of resurrecting the stale transcript.)
 	try {
-		stores.chatStore.saveMessages(chatId, outgoing);
+		stores.chatStore.saveMessages(chatId, merged);
 	} catch (err) {
 		console.error(`[chat ${chatId}] write-ahead persist failed:`, err);
 	}
 
-
-
 	// MONEY CHANNEL (wave 4): one collector per request, fed by the agent's
 	// message_end events. Every model call's usage lands in the chat record's
-	// append-only turns log at onFinish — idempotent per turn id, so a
+	// append-only turns log at onFinish — idempotent per turn id.
-	// replayed persist appends once while continuation turns (which share a
-	// response message id) each keep their usage.
 	const turnUsageId = crypto.randomUUID();
 	const steps: CallUsage[] = [];
 	const collectUsage = (usage: Usage) => {
@@ -238,13 +245,12 @@ export async function handleChatRequest(
 	};
 
 	// AGENT CONSTRUCTION BRANCH (docs/probe-teach-split.md §2): the transcript
-	// is the seam — a probe_done tool part (any state) means the probe is
+	// is the seam — a probe_done call in the record means the probe is
 	// concluded: build the TEACHER (planning + the full toolset). Otherwise
 	// the session is still probing: build the PROBER (quiz/ask + probe_done).
 	// Both share this whole composition (write-ahead persist, liveness,
 	// steers, usage, extraction) — only the agent differs.
-	const teaching = outgoing.some((m) => m.parts.some((p) => p.type === "tool-probe_done"));
+	const teaching = hasProbeDone(merged);
-	const role: ModelRole = teaching ? "teacher" : "prober";
 	// BYOK (owner, 2026-09-22): the conversation chain was resolved by the
 	// turn gate above (chat.model override → strong slot → refused) — the
 	// engine build is pure from here; thinking levels clamp natively.
@@ -252,19 +258,18 @@ export async function handleChatRequest(
 	// Provider-qualified stamp (model slots wave): matches the price table's
 	// provider:id keys.
 	const modelId = `${engine.model.provider}:${engine.model.id}`;
-	// Tests inject a factory: the agent is stateless per turn (docs/
+	// Tests inject a factory: the agent is stateless per turn, so each
-	// pi-engine-swap.md §2), so each request builds a fresh one off the
+	// request builds a fresh one off the record — the factory mirrors that
-	// transcript — the factory mirrors that seam exactly.
+	// seam exactly. Wave B: the record IS the agent state (native messages;
+	// the record's id field strips at the wire in toLlmMessages).
 	// CROSS-STREAM SEAM (P2 reconciliation, 2026-09-19): `toolToggles`
 	// rides the build opts as the user-level DELTA map (absent key =
 	// enabled). The definitive toggleable set is TOGGLEABLE_TOOLS — the
 	// sub-agent JOB tools (research/demo/visual/pdf; adjudicated with the
-	// user: quiz/ask/fs/plan/probe_done are always-on). First-class on
+	// user: quiz/ask/fs/plan/probe_done are always-on).
-	// AgentBuildOptions; the factories drop anything explicitly false and
-	// the settings write side rejects unknown keys.
 	const agentOpts: AgentBuildOptions = {
 		engine,
-		messages: recordToPiMessages(outgoing),
+		messages: asAgentMessages(merged),
 		onUsage: collectUsage,
 		toolToggles: effective.agent.tools,
 		// The prompt-override switches (P2, 2026-09-19): same resolution
@@ -273,7 +278,7 @@ export async function handleChatRequest(
 		promptSwitches: effective.agent.prompts,
 	};
 	const constructed: TeachingAgent = buildAgent
-		? buildAgent(outgoing)
+		? buildAgent({ ...agentOpts, teaching })
 		: teaching
 			? createTeacherAgent(
 					{
@@ -310,7 +315,6 @@ export async function handleChatRequest(
 	// transcript, not the money channel); when it's ours, usage flows through
 	// the factory's subscription (wired above via onUsage).
 	try {
-		assertValidUiMessages(outgoing);
 		// THE TURN AS A BACKGROUND OBJECT (owner ruling, 2026-09-25):
 		// runPiTurn executes decoupled from this response — the POST stream
 		// is just the FIRST subscriber (a view). A client disconnect can no
@@ -318,7 +322,7 @@ export async function handleChatRequest(
 		// late views reattach via GET /api/chats/[id]/stream.
 		const handle = runPiTurn({
 			agent: constructed,
-			uiMessages: outgoing,
+			base: merged,
 			// Stream-level failures are provider/transport internals — masked,
 			// like the SDK defaults. Tool-input validation messages never
 			// route through here: they ride the error-result path and reach the
@@ -327,14 +331,14 @@ export async function handleChatRequest(
 				console.error(`[chat ${chatId}] turn error:`, error);
 				return "An error occurred.";
 			},
-			onFinish: (messages, isAborted) => {
+			onFinish: (turnMessages, isAborted) => {
-				persistTurn(stores.chatStore, chatId, messages as UIMessage[], isAborted);
+				// Wave B: the record write is the agent's own final state —
+				// the new messages are the slice past the merged base.
+				const stamped = persistTurn(stores.chatStore, chatId, merged.length, turnMessages, isAborted);
 				// usage log append (idempotent per turn id) — the stats bar
-				// refolds this on the client after the turn settles. messageId
+				// refolds this on the client after the turn settles. The
-				// comes from the id-FILLED list: the bridge's response message
+				// provenance message is the turn's FIRST new assistant message.
-				// already carries its id; the re-fill here is idempotent.
+				const response = stamped.find((m) => (m as { role?: string }).role === "assistant");
-				const filled = withMessageIds(messages as UIMessage[]);
-				const response = [...filled].reverse().find((m) => m.role === "assistant");
 				if (response && steps.length > 0) {
 					stores.chatStore.appendTurnUsage(chatId, {
 						id: turnUsageId,
@@ -345,9 +349,7 @@ export async function handleChatRequest(
 					});
 				}
 				// GRAPH GATE (settings-storage wave, 2026-09-19): the write channel —
-				// extraction, its auditor — dies with the master switch. (The deeper
+				// extraction, its auditor — dies with the master switch.
-				// pipeline knobs — embedding/clustering/labeling — gate inside the
-				// pipeline and its consumers, later waves, via the same resolved view.)
 				if (extractionEnabled(effective.graph)) {
 					// Fresh per-turn read of the graph section's chunk budget
 					// (extraction-UX redesign, 2026-09-24): the trigger compares

src/server/chats.ts

@@ -1,5 +1,6 @@
 import { abortExtraction, extractionStatuses } from "../agent/subagents/extraction.ts";
 import { coverageOf } from "../core/coverage.ts";
+import { projectNative } from "../core/projection.ts";
 import { deleteChatTraces, type ChatDeleteMode, type ChatDeletionStats } from "../core/graph-deletion.ts";
 import { titleFromPrompt } from "../core/contracts.ts";
 import type { UIMessage } from "ai";
@@ -141,7 +142,9 @@ export function sessionCoverage(chatId: string): SessionCoverage | null {
 	const record = stores.chatStore.getChat(chatId);
 	if (!record) return null;
 	const entries = stores.graphStore.readCoverage();
-	const cov = coverageOf(record.messages as UIMessage[], entries, chatId);
+	// Wave B: the record is native history — coverage reads through the
+	// projection (same view the extraction pipeline folds).
+	const cov = coverageOf(projectNative(record.messages), entries, chatId);
 	let lastFoldedAt: string | null = null;
 	for (const entry of entries) {
 		if (entry.chatId !== chatId) continue;

src/server/jobs.ts

@@ -31,7 +31,6 @@
  * be a different object in each).
  */
 
-import type { UIMessage } from "ai";
 import {
 	buildAbortSteer,
 	buildSubagentSteer,
@@ -40,13 +39,16 @@ import {
 	type JobRecord,
 	type SteerMessage,
 } from "../core/contracts.ts";
-import { findPendingToolCall } from "../core/pending.ts";
+import type { TurnInput } from "../core/input-events.ts";
+import { danglingQuestionOf } from "../core/native-messages.ts";
 import { fireJobAbort, isJobLive } from "../agent/subagents/aborts.ts";
 import { stores } from "./stores.ts";
 import { isTurnRunning } from "./turn-liveness.ts";
 
-/** Fires one server-side teacher turn: (chatId, messages) → HTTP-ish status. */
+/** Fires one server-side teacher turn: (chatId, input) → HTTP-ish status.
-export type TurnRunner = (chatId: string, messages: UIMessage[]) => Promise<number>;
+ *  Wave B: the input is the STEER EVENT — the handler appends the marker
+ *  natively under its own turn claim (one composition for every turn). */
+export type TurnRunner = (chatId: string, input: TurnInput) => Promise<number>;
 
 /** Re-runs a job's sub-agent loop (crash recovery for orphaned jobs). */
 export type JobRespawn = (jobId: string) => void;
@@ -110,10 +112,11 @@ function delay(ms: number): Promise<void> {
 	return new Promise((resolve) => setTimeout(resolve, ms));
 }
 
-/** The job a steer belongs to, if it is a job steer (result/abort/context);
+/** The job a steer belongs to, if it is a job steer (result/abort);
  *  probe-handoff steers have no job — null. */
 function jobIdOf(steer: SteerMessage): string | null {
-	return (steer.metadata as { subagentResult?: { jobId: string } }).subagentResult?.jobId ?? null;
+	const details = steer.details as { jobId?: string } | undefined;
+	return typeof details?.jobId === "string" ? details.jobId : null;
 }
 
 /** Finalize a delivered steer's job bookkeeping — job steers only. */
@@ -167,32 +170,22 @@ export function deliverJobResult(steer: SteerMessage): Promise<void> {
  * copies of the same steer id (a live React duplicate-key warning the
  * owner hit 2026-09-18; withMessageIds only heals it at onFinish).
  */
-export function claimSteers(
+export function claimSteers(chatId: string): SteerMessage[] {
-	chatId: string,
-	incoming?: ReadonlyArray<UIMessage>,
-): SteerMessage[] {
 	const s = state();
 	const queue = s.queues.get(chatId);
 	if (!queue || queue.length === 0) return [];
-	const record = stores.chatStore.getChat(chatId);
+	s.queues.delete(chatId);
-	if (!record) return []; // the handler validated the chat; defensive only
+	// The caller holds the turn registry (chat-handler claims after
-	const claimed: SteerMessage[] = [];
+	// beginTurn), so the write-ahead persist is imminent and durable:
+	// every queued steer is claimed — its delivery is THIS turn's job.
+	// Steers already in the transcript (a wake raced in) still finalize
+	// here; the handler's append filter (steerDelivered) keeps exactly
+	// one copy in the record.
+	const claimed = queue.map((entry) => entry.steer);
 	for (const entry of queue) {
-		if (
-			steerDelivered(record.messages, entry.steer.id) ||
-			incoming?.some((m) => m.id === entry.steer.id)
-		) {
-			// A wake already landed it — or this turn's own request already
-			// carries it (the pump path): the delivery is done either way,
-			// just finish the bookkeeping. NEVER append twice.
 		finalizeSteer(entry.steer);
-		} else {
-			claimed.push(entry.steer);
-			finalizeSteer(entry.steer); // delivery is now the client turn's job
-		}
 		entry.resolve();
 	}
-	s.queues.delete(chatId);
 	return claimed;
 }
 
@@ -256,12 +249,13 @@ export function abortJob(jobId: string): AbortOutcome {
 }
 
 function chatIdOf(steer: SteerMessage): string {
-	// The probe handoff carries its chat directly (the job record would
+	// The probe handoff carries its chat directly in the marker details (the
-	// say it too, but the metadata is the cheap path).
+	// job record would say it too, but the details are the cheap path).
-	const handoff = (steer.metadata as { probeHandoff?: { chatId: string } }).probeHandoff;
+	if (steer.customType === "probe-handoff") {
-	if (handoff) return handoff.chatId;
+		return (steer.details as { chatId: string }).chatId;
-	// The chat is resolvable from the job record; the steer's metadata
+	}
-	// carries jobId, which indexes the store.
+	// The chat is resolvable from the job record; the steer's details
+	// carry jobId, which indexes the store.
 	const jobId = jobIdOf(steer);
 	const job = jobId ? stores.jobStore.getJob(jobId) : undefined;
 	return job?.chatId ?? "";
@@ -334,9 +328,11 @@ async function pump(chatId: string): Promise<void> {
 				continue;
 			}
 
-			// Fire the server-side teacher turn. A 409 = a client turn raced
+			// Fire the server-side teacher turn (the steer EVENT: the handler
-			// in between idle and firing — back off and retry the same steer.
+			// appends the marker natively under its own turn claim). A 409 = a
-			const status = await s.turnRunner(chatId, [...fresh.messages, entry.steer]).catch((err: unknown) => {
+			// client turn raced in between idle and firing — back off and
+			// retry the same steer.
+			const status = await s.turnRunner(chatId, { type: "steer", steer: entry.steer }).catch((err: unknown) => {
 				console.error(`[steer ${steerId}] wake turn crashed:`, err);
 				return -1;
 			});
@@ -387,22 +383,23 @@ function failJob(jobId: string, err: Error): void {
 
 /**
  * Wait until the chat can take a wake turn: no turn in flight AND no
- * unanswered question part (provider conversion would break). Poll; the
+ * unanswered question call (the record's dangling question — the answer
- * learner may take arbitrarily long to answer, and that is correct — the
+ * arrives as its tool result, and no turn may run in the window). Poll;
- * steer fires right after their continuation completes.
+ * the learner may take arbitrarily long to answer, and that is correct —
+ * the steer fires right after their answer turn completes.
  */
 async function waitForIdle(chatId: string): Promise<void> {
 	for (;;) {
 		const record = stores.chatStore.getChat(chatId);
 		if (!record) return;
-		const blocked = isTurnRunning(chatId) || findPendingToolCall(record.messages) !== null;
+		const blocked = isTurnRunning(chatId) || danglingQuestionOf(record.messages) !== null;
 		if (!blocked) {
 			await delay(GRACE_MS);
 			const recheck = stores.chatStore.getChat(chatId);
 			if (
 				!isTurnRunning(chatId) &&
 				recheck &&
-				findPendingToolCall(recheck.messages) === null
+				danglingQuestionOf(recheck.messages) === null
 			) {
 				return;
 			}

src/server/pi/record-adapter.ts

@@ -1,190 +0,0 @@
-import type { UIMessage } from "ai";
-import type { AgentMessage } from "@earendil-works/pi-agent-core";
-import type { AssistantMessage, Message, ToolResultMessage } from "@earendil-works/pi-ai";
-import { HANDOFF_TEXT, verdictText } from "../../core/contracts/chat.ts";
-
-/**
- * The record → pi-ai transcript adapter (docs/pi-engine-swap.md §4). The
- * persisted UIMessage record IS the source of truth; every turn builds a
- * fresh agent from it (the stateless per-turn decision). This replaces the
- * SDK's convertToModelMessages with an owned, explicit mapping:
- *
- * - user text parts → UserMessage text content.
- * - SYSTEM DATA PARTS (the custom-message scheme, 2026-09-12): the wake and
- *   verdict messages carry ONLY a marker part — no human text exists to
- *   drop, so the ADAPTER flattens them: data-verdict → verdictText(),
- *   data-probe-handoff → HANDOFF_TEXT (core/contracts/chat.ts owns both —
- *   single source, so the model-facing wording can't drift from the seam).
- *   Other data parts (artifacts, plan blocks) are dropped as before: they
- *   are UI history; the steer briefs ride their text twin (payload, not
- *   boilerplate — those texts are content the sub-agent produced).
- * - assistant text/reasoning/tool parts → one AssistantMessage whose
- *   content blocks mirror the part order; tool parts become ToolCall
- *   blocks (output-error parts keep their rawInput).
- * - answered tool parts (output-available) → ToolResultMessage after the
- *   assistant message, JSON-encoded like the model saw it live.
- * - errored tool parts (output-error) → an isError ToolResultMessage
- *   carrying the validation message (the model's retry context).
- * - DANGLING calls (input-available, never answered — an aborted turn)
- *   → a synthesized interrupted ToolResultMessage. THE HARD INVARIANT:
- *   an assistant message with tool calls must be followed by tool
- *   results, or providers reject the request outright.
- */
-
-const INTERRUPTED = "The question was interrupted — the learner never answered; continue without holding a result for it.";
-
-function textOf(part: { text?: string }): string {
-	return typeof part.text === "string" ? part.text : "";
-}
-
-/** Encode a tool output the way the model saw it live (string verbatim, object JSON). */
-function toolResultText(output: unknown): string {
-	return typeof output === "string" ? output : JSON.stringify(output);
-}
-
-function zeroUsage() {
-	return {
-		input: 0,
-		output: 0,
-		cacheRead: 0,
-		cacheWrite: 0,
-		totalTokens: 0,
-		cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0, total: 0 },
-	};
-}
-
-/** The model-facing text of a marker-only user message, or null when the
- *  message has no model face at all (UI-only data parts). */
-function systemTextOf(message: { parts: ReadonlyArray<{ type: string; data?: unknown }> }): string | null {
-	for (const part of message.parts) {
-		if (part.type === "data-verdict") {
-			return verdictText((part.data as { accepted?: unknown } | undefined)?.accepted === true);
-		}
-		if (part.type === "data-probe-handoff") return HANDOFF_TEXT;
-	}
-	return null;
-}
-
-export function recordToPiMessages(messages: UIMessage[]): Message[] {
-	const out: AgentMessage[] = [];
-
-	for (const message of messages) {
-		if (message.role === "user") {
-			const texts = message.parts
-				.filter((p) => p.type === "text")
-				.map((p) => textOf(p as { text?: string }))
-				.filter((t) => t.length > 0);
-			// The custom-message scheme: a marker-only message (verdict,
-			// handoff) flattens to its canonical model-facing text — the
-			// wording lives in the adapter's reach (core contracts), never
-			// authored as fake human speech in the transcript.
-			if (texts.length === 0) {
-				const flat = systemTextOf(message);
-				if (flat === null) continue; // pure UI data part, no model face
-				texts.push(flat);
-			}
-			out.push({
-				role: "user",
-				content: texts.map((text) => ({ type: "text" as const, text })),
-				timestamp: Date.now(),
-			});
-		} else if (message.role === "assistant") {
-			const content: AssistantMessage["content"] = [];
-			const results: ToolResultMessage[] = [];
-			let answered = false;
-
-			for (const part of message.parts) {
-				if (part.type === "text") {
-					const text = textOf(part);
-					if (text) content.push({ type: "text", text });
-				} else if (part.type === "reasoning") {
-					const text = textOf(part);
-					if (text) content.push({ type: "thinking", thinking: text });
-				} else if (part.type === "step-start") {
-					// presentation-only; the pi loop re-derives turn boundaries
-				} else if (part.type.startsWith("tool-")) {
-					const tool = part.type.slice("tool-".length);
-					const p = part as unknown as {
-						toolCallId: string;
-						state: string;
-						input?: unknown;
-						rawInput?: unknown;
-						output?: unknown;
-						errorText?: string;
-					};
-					// The call block (any state — the model authored it).
-					if (p.state === "input-available" || p.state === "input-streaming" || p.state === "output-available") {
-						content.push({
-							type: "toolCall",
-							id: p.toolCallId,
-							name: tool,
-							arguments: (p.input ?? {}) as Record<string, unknown>,
-						});
-					} else if (p.state === "output-error") {
-						content.push({
-							type: "toolCall",
-							id: p.toolCallId,
-							name: tool,
-							arguments: (p.rawInput ?? p.input ?? {}) as Record<string, unknown>,
-						});
-					}
-					// The result, if any.
-					if (p.state === "output-available") {
-						results.push({
-							role: "toolResult",
-							toolCallId: p.toolCallId,
-							toolName: tool,
-							content: [{ type: "text", text: toolResultText(p.output) }],
-							isError: false,
-							timestamp: Date.now(),
-						});
-						answered = true;
-					} else if (p.state === "output-error") {
-						results.push({
-							role: "toolResult",
-							toolCallId: p.toolCallId,
-							toolName: tool,
-							content: [{ type: "text", text: p.errorText ?? "The tool call failed validation." }],
-							isError: true,
-							timestamp: Date.now(),
-						});
-						answered = true;
-					}
-				}
-				// data-* parts (plan blocks, artifacts, markers) never reach the model.
-			}
-
-			if (content.length === 0) continue; // presentation-only message
-			out.push({
-				role: "assistant",
-				content,
-				api: "openai-completions",
-				provider: "openrouter",
-				model: "replayed",
-				usage: zeroUsage(),
-				stopReason: content[content.length - 1]!.type === "toolCall" ? "toolUse" : "stop",
-				timestamp: Date.now(),
-			});
-			// Dangling calls: synthesize the interrupted result so providers
-			// never see an unanswered tool call (the hard invariant).
-			if (!answered) {
-				for (const block of content) {
-					if (block.type === "toolCall" && !results.some((r) => r.toolCallId === block.id)) {
-						results.push({
-							role: "toolResult",
-							toolCallId: block.id,
-							toolName: block.name,
-							content: [{ type: "text", text: INTERRUPTED }],
-							isError: false,
-							timestamp: Date.now(),
-						});
-					}
-				}
-			}
-			out.push(...results);
-		}
-		// role "system" never appears in records (system prompt is composed separately).
-	}
-
-	return out as Message[];
-}

src/server/pi/ui-stream.ts

@@ -1,6 +1,8 @@
-import type { Agent, AgentEvent } from "@earendil-works/pi-agent-core";
+import type { Agent, AgentEvent, AgentMessage } from "@earendil-works/pi-agent-core";
 import type { UIMessage } from "ai";
 import { QUESTION_TOOLS } from "../../core/pending.ts";
+import type { LhMessage } from "../../core/native-messages.ts";
+import { projectNative } from "../../core/projection.ts";
 
 /**
  * The UI-stream bridge (docs/pi-engine-swap.md §5): runs one agent turn and
@@ -23,9 +25,10 @@ import { QUESTION_TOOLS } from "../../core/pending.ts";
  *   tool-input-error instead and NEVER becomes input-available, so a
  *   malformed question can never mount the dock (the live modal-realism
  *   crash: GLM double-encoded `options` as a JSON string).
- * - The persisted message is assembled from the SAME parts the client
+ * - The WIRE assembly (below) is the client view only (Wave B): the
- *   assembles (the processUIMessageStream shapes), so every downstream
+ *   record write is the agent's own native final state — the projection
- *   consumer (phases, plan blocks, pending, extraction) is unchanged.
+ *   (core/projection.ts) reproduces the client's part shapes for every
+ *   consumer (phases, plan blocks, pending, extraction) until Wave D.
  *
  * BACKGROUND-TURN RUNNER (owner ruling, 2026-09-25): a turn executes as a
  * server-side background object decoupled from any single HTTP response —
@@ -42,12 +45,17 @@ type Chunk = Record<string, unknown> & { type: string };
 export interface PiTurnSpec {
 	/** The per-turn agent (stateless engine — built from the record). */
 	agent: Agent;
-	/** The outgoing request messages (write-ahead persisted already). */
+	/** The turn's base: the native record + this turn's appends
-	uiMessages: UIMessage[];
+	 *  (write-ahead persisted already). Wave B: the agent's context and
+	 *  the record share one shape; onFinish receives the full agent state
+	 *  and the caller persists the slice past base.length. */
+	base: LhMessage[];
 	/** The handler's error-unmasking policy (validation messages stay readable). */
 	onError?: (error: unknown) => string;
-	/** The canonical end-of-turn seam: persist + usage + extraction + endTurn. */
+	/** The canonical end-of-turn seam: persist + usage + extraction + endTurn.
-	onFinish: (messages: UIMessage[], isAborted: boolean) => void;
+	 *  Receives the agent's FULL final state (native messages) — the turn's
+	 *  new messages are the slice past base.length. */
+	onFinish: (messages: AgentMessage[], isAborted: boolean) => void;
 }
 
 /** One view onto a running turn: push() replays/streams a chunk, done()
@@ -117,15 +125,22 @@ interface ToolPart {
 }
 
 export function runPiTurn(spec: PiTurnSpec): PiTurnHandle {
-	const { agent, uiMessages, onFinish } = spec;
+	const { agent, base, onFinish } = spec;
 
 	// The streaming target: continuation (same id, parts appended to a copy
-	// of the existing message) or a fresh assistant message.
+	// of the existing message) or a fresh assistant message. The continuation
-	const last = uiMessages[uiMessages.length - 1];
+	// rule is the CLIENT's: it keys on the last UIMessage's id — read through
-	const continuing = last?.role === "assistant";
+	// the projection (the record is native; a turn after an answer continues
+	// the group that carries the answered quiz, which is the projection's
+	// last message).
+	const projected = projectNative(base);
+	const last = projected[projected.length - 1] as
+		| { id?: string; role?: string; parts?: UIMessage["parts"] }
+		| undefined;
+	const continuing = last?.role === "assistant" && typeof last.id === "string";
 	const messageId =
 		(continuing && last.id) || `msg_${Date.now().toString(36)}_${crypto.randomUUID().slice(0, 8)}`;
-	const baseParts: UIMessage["parts"] = continuing ? [...last.parts] : [];
+	const baseParts: UIMessage["parts"] = continuing && last.parts ? [...last.parts] : [];
 	const parts: UIMessage["parts"] = [...baseParts];
 
 	// Stable, collision-free part ids across continuation runs (reasoning
@@ -174,11 +189,11 @@ export function runPiTurn(spec: PiTurnSpec): PiTurnHandle {
 	send({ type: "start", messageId });
 
 	const settleWith = () => {
-		const assembled: UIMessage = { id: messageId, role: "assistant", parts };
+		// Wave B: the record write is the agent's OWN final state (native
-		// The SDK's onFinish shape: the input copy stays, the extended
+		// history — signatures, usage, provider stamps all real); the wire
-		// response copy appends (persistTurn's withMessageIds dedupe
+		// assembly above served the client view only. Copy the array: the
-		// keeps the last occurrence).
+		// agent may outlive this call's read.
-		onFinish([...uiMessages, assembled], sawAbort);
+		onFinish([...agent.state.messages], sawAbort);
 	};
 
 	const handle = (event: AgentEvent) => {

src/server/turn-service.ts

@@ -4,69 +4,85 @@
  * implementing. Each takes its dependencies explicitly (storage ports, the
  * job runner) — no module here imports an adapter.
  *
- *   persistTurn        — the canonical state write (client + agent messages)
+ *   persistTurn        — the canonical state write (Wave B: native history;
+ *                        id stamping, placeholder filtering, plan-block
+ *                        emission, abort-partial persistence)
  *   triggerExtraction  — the graph write channel: fires the extraction
  *                        pipeline (the sole graph writer) once a chat
- *                        crosses the v1 quiz-answer threshold. The trigger
+ *                        crosses the token-budget threshold.
- *                        mechanism is a v1 placeholder — this seam is the
- *                        ONLY thing to swap when a better one lands.
  *
  * Logs are the minimal-observability baseline: one line per failure, tagged
  * [chat <id>] — structured logging lands behind these seams later.
  */
 
-import type { UIMessage } from "ai";
+import type { AgentMessage } from "@earendil-works/pi-agent-core";
-import { withPlanBlocks } from "../core/plan-blocks.ts";
+import type { ToolResultMessage } from "@earendil-works/pi-ai";
+import type { LhMessage } from "../core/native-messages.ts";
+import { newMessageId } from "../core/native-messages.ts";
+import { QUESTION_TOOLS } from "../core/pending.ts";
+import { planBlocksFor } from "../core/plan-blocks.ts";
+import { projectNative } from "../core/projection.ts";
 import { coverageOf } from "../core/coverage.ts";
 import type { ChatStore, GraphStore } from "../core/ports.ts";
 import type { ExtractionPipeline } from "../agent/subagents/extraction.ts";
 import { ModelsNotConfiguredError, ProviderKeyMissingError } from "../core/settings.ts";
 
 /**
- * The canonical state write: the client owns the message list between turns
+ * The canonical state write (Wave B, owner-approved 2026-09-26): append the
- * (useChat); this persists client messages + the agent response. Persists
+ * turn's own messages — the agent loop's native history, provider/model/
- * even when aborted — the partial transcript (including any pending
+ * usage/thinkingSignature stamped by pi itself. Persists even when aborted
- * question part) is what makes resume work.
+ * — the partial transcript (including a pending question's unanswered
+ * call) is what makes resume work.
+ *
+ * - Id stamping: pi messages carry no id; the record's identity needs one
+ *   per message (client keys, append-only adoption, the continuation
+ *   seam). Minted here, at the single canonical write.
+ * - Placeholder filtering: a cleanly-posed question's synthetic
+ *   "question posed" result is an in-memory loop device (Wave A's
+ *   terminate) — NEVER persisted (fork 1: the record ends at the
+ *   unanswered call; the learner's answer arrives as the real tool
+ *   result). Errored question calls DO persist — the model's retry
+ *   context.
+ * - Plan blocks: one frozen snapshot per successful plan_init call,
+ *   idempotent (persist replays are safe).
+ *
+ * Returns the stamped new messages (usage provenance reads them).
  */
-/**
+export function persistTurn(
- * The SDK assigns assistant-message ids CLIENT-side (useChat); the server's
+	chatStore: ChatStore,
- * onFinish synthesis leaves them EMPTY. A message persisted only server-side
+	chatId: string,
- * (the last turn's, or a wake turn's — nobody re-POSTs it with a client id)
+	baseCount: number,
- * would otherwise land in the record with id "" — and two of those in one
+	turnMessages: readonly AgentMessage[],
- * transcript break React keys (the chat map) and steer-dedup lookups. Fill any
+	isAborted: boolean,
- * missing id here, at the single canonical write: client-authored ids are
+): LhMessage[] {
- * NEVER touched (the client's next POST still carries them verbatim).
- */
-export function withMessageIds(messages: UIMessage[]): UIMessage[] {
-	const filled = messages.map((m) =>
-		m.id ? m : { ...m, id: `msg_${Date.now().toString(36)}_${crypto.randomUUID().slice(0, 8)}` },
-	);
-	// Same id twice = the SDK's continuation merge couldn't happen in place
-	// (continuation coalescing appends a user-role steer AFTER the assistant
-	// message being continued, so onFinish carries the input copy AND the
-	// extended response copy under one id). Keep the LAST occurrence — it is
-	// the SDK's final merge state (a superset of the earlier copy).
-	const seen = new Set<string>();
-	const deduped: UIMessage[] = [];
-	for (let i = filled.length - 1; i >= 0; i--) {
-		const m = filled[i]!;
-		if (seen.has(m.id)) continue;
-		seen.add(m.id);
-		deduped.unshift(m);
-	}
-	return deduped;
-}
-
-export function persistTurn(chatStore: ChatStore, chatId: string, messages: UIMessage[], isAborted: boolean): void {
 	try {
-		const deduped = withMessageIds(messages);
+		const record = chatStore.getChat(chatId);
-		// Plan-block emission (wave 4): blocks are frozen transcript content —
+		if (!record) return [];
-		// attached here, once, at the canonical state write. The tree was
+		const stamped: LhMessage[] = [];
-		// saved by the plan tool during the turn; snapshots derive now.
+		for (const m of turnMessages.slice(baseCount)) {
-		const tree = chatStore.getChat(chatId)?.tree;
+			const message = m as LhMessage;
-		chatStore.saveMessages(chatId, withPlanBlocks(deduped, tree));
+			// The placeholder question result: loop device, never a record fact.
+			if (
+				(message as { role?: string }).role === "toolResult" &&
+				(QUESTION_TOOLS as readonly string[]).includes((message as ToolResultMessage).toolName) &&
+				!(message as ToolResultMessage).isError
+			) {
+				continue;
+			}
+			stamped.push(message.id ? message : ({ ...message, id: newMessageId() } as LhMessage));
+		}
+		const tree = record.tree;
+		const blocks = planBlocksFor(
+			record.messages,
+			stamped,
+			tree,
+			projectNative([...record.messages, ...stamped]),
+		);
+		chatStore.saveMessages(chatId, [...record.messages, ...stamped, ...blocks]);
+		return stamped;
 	} catch (err) {
 		console.error(`[chat ${chatId}] persist failed:`, err, { isAborted });
+		return [];
 	}
 }
 
@@ -74,15 +90,11 @@ export function persistTurn(chatStore: ChatStore, chatId: string, messages: UIMe
  * The graph write channel (vision §1 construction): the extraction pipeline
  * (extractor → auditor → merger — the sole graph writer) runs ASYNC once a
  * chat's UNCOVERED transcript tokens reach the chunk budget
- * (vision-extraction-coverage.md, 2026-09-15 — replacing the old
+ * (vision-extraction-coverage.md, 2026-09-15). Coverage reads through the
- * every-3-quiz-answers count: content size is the honest signal, and
+ * projection (the record is native history; the extraction view stays
- * quiz-less sessions extract too). The budget is the graph section's
+ * client-shaped until Wave D). Fire-and-forget — never blocks the turn;
- * extractionChunkTokens setting (extraction-UX redesign, 2026-09-24) —
+ * failures are logged by the pipeline and leave coverage untouched, so the
- * the composition root passes the per-turn effective read (chat-handler
+ * next trigger (or the manual extract button) re-runs what's left.
- * resolves fresh per turn, same as every other gate). The pipeline
- * itself extracts only the uncovered batches. Fire-and-forget — never blocks the turn; failures are
- * logged by the pipeline and leave coverage untouched, so the next trigger
- * (or the manual extract button) re-runs what's left.
  *
  * Deliberately isolated in this one seam — the pipeline is
  * trigger-agnostic. Skipped under tests: scripted chats are fixtures, not
@@ -98,7 +110,7 @@ export function triggerExtraction(
 	try {
 		const record = deps.chatStore.getChat(chatId);
 		if (!record) return;
-		const covered = coverageOf(record.messages as UIMessage[], deps.graphStore.readCoverage(), chatId);
+		const covered = coverageOf(projectNative(record.messages), deps.graphStore.readCoverage(), chatId);
 		if (covered.uncoveredTokens < chunkTokens) return;
 		void extraction.runExtraction(chatId).catch((err) => {
 			// BYOK (owner, 2026-09-22) + key presence (provider-key interlude,
@@ -119,4 +131,3 @@ export function triggerExtraction(
 		console.error(`[chat ${chatId}] extraction trigger failed:`, err);
 	}
 }
-

src/store/chats.ts

@@ -12,9 +12,10 @@ import * as path from "node:path";
 import { PATHS } from "../../config.ts";
 import type { ChatStore } from "../core/ports.ts";
 import type { ChatRecord, ChatSettings, ChatSummary, ExtractionRunUsage, PlanTree, TurnUsage } from "../core/contracts.ts";
-import type { UIMessage } from "ai";
+import type { LhMessage } from "../core/native-messages.ts";
 import { findPendingToolCall } from "../core/pending.ts";
 import { phaseAt3 } from "../core/phases.ts";
+import { projectNative } from "../core/projection.ts";
 
 function chatFile(id: string): string {
 	if (!/^[A-Za-z0-9_-]+$/.test(id)) throw new Error(`Invalid chat id: ${id}`);
@@ -51,7 +52,14 @@ function listChats(): ChatSummary[] {
 			.filter((f) => f.endsWith(".json"))
 			.map((f) => getChat(f.slice(0, -5)))
 			.filter((r): r is ChatRecord => r !== null)
-			.map(({ messages, tree, turns, extractions, ...summary }) => ({
+			.map(({ messages, tree, turns, extractions, ...summary }) => {
+				// Per-record isolation (Wave B): a record whose messages fail the
+				// projection (e.g. pre-Wave-B UIMessage-format scratch — the
+				// zero-back-compat wipe makes these "corrupt") must not blank the
+				// whole sidebar — same isolation getChat's per-file catch gives.
+				try {
+					const projected = projectNative(messages);
+					return {
 						// turns and extractions stay out of the list payload (list =
 						// summaries; usage aggregates ride the full record, the picker
 						// never needs them).
@@ -60,19 +68,27 @@ function listChats(): ChatSummary[] {
 						// Record-derived status for the session picker: phase from the
 						// transcript's explicit markers (probe_done / plan_init — the
 						// event-driven phases, docs/probe-teach-split.md §4), pending
-				// question from the last unanswered quiz/ask part. Liveness (busy)
+						// question from the last unanswered quiz/ask part — both read
-				// is NOT record-derived — the API route merges it (ChatListItem).
+						// through the one-way projection. Liveness (busy) is NOT
-				phase: phaseAt3(messages),
+						// record-derived — the API route merges it (ChatListItem).
-				pendingQuestion: findPendingToolCall(messages) !== null,
+						phase: phaseAt3(projected),
-			}))
+						pendingQuestion: findPendingToolCall(projected) !== null,
+					};
+				} catch (err) {
+					console.error(`[chat ${summary.id}] summary projection failed:`, err);
+					return null;
+				}
+			})
+			.filter((s): s is ChatSummary => s !== null)
 			.sort((a, b) => b.updatedAt.localeCompare(a.updatedAt));
 	} catch {
 		return [];
 	}
 }
 
-/** Persist the full message list (client state + new response) after a turn. */
+/** Persist the full native message list (the record IS the agent state —
-function saveMessages(id: string, messages: UIMessage[]): void {
+ *  Wave B: replay is state.messages = record.messages). */
+function saveMessages(id: string, messages: LhMessage[]): void {
 	const record = getChat(id);
 	if (!record) throw new Error(`Chat not found: ${id}`);
 	record.messages = messages;

tests/chat-flow.test.ts

@@ -2,13 +2,15 @@
  * Scripted integration test — the full teacher loop with zero tokens:
  *
  *   learner opens chat → faux model calls `quiz` → server streams + persists
- *   → client grades and sends the answer back as the tool output
+ *   → client grades and sends the ANSWER EVENT back
  *   → faux model reacts → transcript persisted.
  *
  * Drives handleChatRequest directly (plain Request/Response — no Next server
  * needed) with a scripted pi engine (pi-ai's faux provider, docs/
- * pi-engine-swap.md §7): the quiz bridge is gone, the tool part IS the
+ * pi-engine-swap.md §7). Wave B: POSTs carry ONE INPUT EVENT (never a client
- * pending state, and the persisted transcript is the resume record.
+ * transcript), the record is pi-native agent history (read through the
+ * projection where a part shape is pinned), and the answer arrives as the
+ * question call's real tool result (fork 1, owner 2026-09-26).
  */
 
 import assert from "node:assert/strict";
@@ -28,13 +30,12 @@ import { handleChatRequest } from "../src/server/chat-handler.ts";
 import { effectiveSettings } from "../src/server/stores.ts";
 import { isTurnRunning } from "../src/server/turn-liveness.ts";
 import { abortTurn, runningTurn, settledTurnResponse } from "../src/server/turn-runs.ts";
-import { recordToPiMessages } from "../src/server/pi/record-adapter.ts";
 import { chatStore } from "../src/store/chats.ts";
 import { buildAnswer, coerceCorrectAnswer, normalizeOptions, resolveCorrect, type QuestionData } from "../src/core/question-core.ts";
-import { findPendingToolCall } from "../src/core/pending.ts";
+import { danglingQuestionOf, newAnswerResult } from "../src/core/native-messages.ts";
+import { projectNative } from "../src/core/projection.ts";
 import type { PiEngine } from "../src/agent/models.ts";
-import type { TeachingAgent } from "../src/agent/teacher-agent.ts";
+import type { LhMessage } from "../src/core/native-messages.ts";
-import type { UIMessage } from "ai";
 import { PATHS } from "../config.ts";
 
 // The key-presence turn gate (provider-key interlude, 2026-09-25): scripted
@@ -84,10 +85,27 @@ function defaultLesson(calls: string[][]): FauxResponseStep[] {
 }
 
 /** The handler seam (stateless per turn): each request builds a fresh agent
- *  off the transcript it is about to run — the factory tests inject. */
+ *  off the record it is about to run — the factory tests inject. Wave B: the
-function agentFactory(engine: PiEngine) {
+ *  handler hands the factory the NATIVE build options (the record IS the
-	return (outgoing: UIMessage[]): TeachingAgent =>
+ *  agent state — no adapter conversion). */
-		createTeacherAgent(undefined, { engine, messages: recordToPiMessages(outgoing) });
+function agentFactory(engine: PiEngine): Parameters<typeof handleChatRequest>[1] {
+	return (opts) => createTeacherAgent(undefined, { engine, messages: opts.messages });
+}
+
+/** The graded answer a client sends for a quiz (the shared grading seam). */
+function gradedAnswer(input: typeof QUIZ_INPUT, values: string[]) {
+	const options = normalizeOptions(input.options);
+	const qd: QuestionData = {
+		id: "call-1",
+		kind: "quiz",
+		question: input.question,
+		mode: "single-select",
+		options,
+		correctIndices: resolveCorrect(coerceCorrectAnswer(input.correctAnswer), options).indices,
+		explanation: input.explanation,
+		createdAt: new Date().toISOString(),
+	};
+	return buildAnswer(qd, { values });
 }
 
 async function drain(res: Response): Promise<string> {
@@ -137,15 +155,16 @@ function abortableTeacher(): PiEngine {
 	return { model: faux.getModel(), streamFn: faux.streamSimple };
 }
 
-function post(chatId: string, messages: unknown[]): Request {
+function post(chatId: string, input: unknown): Request {
 	return new Request("http://test/api/chat", {
 		method: "POST",
 		headers: { "Content-Type": "application/json" },
-		body: JSON.stringify({ chatId, messages }),
+		// Wave B: the input-events contract — one explicit event per POST,
+		// never a client transcript.
+		body: JSON.stringify({ chatId, input }),
 	});
 }
 
-
 /** BYOK turn gate (owner, 2026-09-22): no factory floor — a chat needs a
  *  conversation model before any turn streams. The scripted tests give
  *  each chat a per-chat pin exactly like the setup flow does in
@@ -174,68 +193,69 @@ describe("teacher chat flow (scripted model)", () => {
 		createdChats.push(chat.id);
 
 		// ── Turn 1: learner opens with a topic; teacher probes with a quiz ──
-		const firstUser = { id: "u1", role: "user", parts: [{ type: "text", text: "teach me the solar system" }] };
+		await drain(await handleChatRequest(post(chat.id, { type: "text", text: "teach me the solar system" }), agentFactory(engine)));
-		await drain(await handleChatRequest(post(chat.id, [firstUser]), agentFactory(engine)));
 
 		const saved1 = chatStore.getChat(chat.id)!;
+		// Native record: user + assistant (fork 1 — the clean question's
+		// placeholder result never persists, so the record ends at the call).
 		assert.equal(saved1.messages.length, 2, "user message + assistant response persisted");
 		const assistantMsg = saved1.messages[1]!;
 		assert.equal(assistantMsg.role, "assistant");
 
-		const reasoningPart = assistantMsg.parts.find((p) => p.type === "reasoning");
+		const thinking = assistantMsg.content.find((b) => b.type === "thinking");
-		assert.ok(reasoningPart && reasoningPart.type === "reasoning", "reasoning part streamed + persisted");
+		assert.ok(thinking && thinking.type === "thinking", "thinking block streamed + persisted");
-		assert.match((reasoningPart as { text?: string }).text!, /Probe the basics/);
+		assert.match((thinking as { thinking?: string }).thinking!, /Probe the basics/);
 
-		const quizPart = assistantMsg.parts.find((p) => p.type === "tool-quiz");
+		const quizCall = assistantMsg.content.find((b) => b.type === "toolCall" && b.name === "quiz");
-		assert.ok(quizPart && quizPart.type === "tool-quiz", "quiz tool part persisted");
+		assert.ok(quizCall && quizCall.type === "toolCall", "quiz tool call persisted");
+		assert.equal((quizCall as { id?: string }).id, "call-1");
+		assert.deepEqual((quizCall as { arguments?: unknown }).arguments, QUIZ_INPUT);
+
+		// The projection pins the client view: reasoning part + a pending
+		// (input-available) quiz part — the dock's mount state.
+		const view1 = projectNative(saved1.messages);
+		const reasoningPart = view1[1]!.parts.find((p) => p.type === "reasoning");
+		assert.ok(reasoningPart && reasoningPart.type === "reasoning", "reasoning part projected");
+		const quizPart = view1[1]!.parts.find((p) => p.type === "tool-quiz");
+		assert.ok(quizPart && quizPart.type === "tool-quiz", "quiz tool part projected");
 		assert.equal((quizPart as { state?: string }).state, "input-available", "unanswered quiz = pending state (resume record)");
 		assert.deepEqual((quizPart as { input?: unknown }).input, QUIZ_INPUT);
 
-		// The pending-question gate sees it.
+		// The pending-question gate sees it (the native seam).
-		const pending = findPendingToolCall(saved1.messages);
+		const pending = danglingQuestionOf(saved1.messages);
 		assert.equal(pending?.toolCallId, "call-1");
 		assert.equal(pending?.tool, "quiz");
 		assert.deepEqual(pending?.input, QUIZ_INPUT);
 
-		// ── The learner answers: client grades, output goes back on the part ──
+		// ── The learner answers: the client grades and posts the ANSWER
-		const options = normalizeOptions(QUIZ_INPUT.options);
+		// EVENT — the answer lands as the call's real tool result. ──
-		const qd: QuestionData = {
+		const answer = gradedAnswer(QUIZ_INPUT, ["Mercury"]);
-			id: "call-1",
-			kind: "quiz",
-			question: QUIZ_INPUT.question,
-			mode: "single-select",
-			options,
-			correctIndices: resolveCorrect(coerceCorrectAnswer(QUIZ_INPUT.correctAnswer), options).indices,
-			explanation: QUIZ_INPUT.explanation,
-			createdAt: new Date().toISOString(),
-		};
-		const answer = buildAnswer(qd, { values: ["Mercury"] });
 		assert.equal(answer.correct, true);
+		await drain(await handleChatRequest(post(chat.id, { type: "answer", toolCallId: "call-1", answer }), agentFactory(engine)));
 
-		const messages2 = saved1.messages.map((m) =>
+		// ── The teacher reacts — the projection groups the reaction into the
-			m.id === assistantMsg.id
+		// SAME assistant view message as the answered quiz (the native
-				? {
+		// grouping canon: consecutive assistant/toolResult messages bounded
-						...m,
+		// by user messages form one group). ──
-						parts: m.parts.map((p) =>
-							p.type === "tool-quiz" ? { ...p, state: "output-available" as const, output: answer } : p,
-						),
-					}
-				: m,
-		);
-		await drain(await handleChatRequest(post(chat.id, messages2), agentFactory(engine)));
-
-		// ── The teacher reacts — as a CONTINUATION of the same assistant message
-		// (the last client message is the assistant message carrying the tool
-		// output, so the new text appends to that message's parts). ──
 		const saved2 = chatStore.getChat(chat.id)!;
-		assert.equal(saved2.messages.length, 2, "the reaction continues the same assistant message");
+		// Native: user, assistant, answer toolResult, reaction assistant.
-		const finalParts = saved2.messages[1]!.parts;
+		assert.equal(saved2.messages.length, 4, "the answer + reaction append natively");
+		assert.equal((saved2.messages[2] as { role?: string }).role, "toolResult", "the graded answer is the call's tool result");
+		const view2 = projectNative(saved2.messages);
+		assert.equal(view2.length, 2, "the reaction continues the same assistant message (one group)");
+		const finalParts = view2[1]!.parts;
 		const textPart = finalParts.find((p) => p.type === "text");
 		assert.ok(textPart && textPart.type === "text", "reaction text appended after the tool part");
 		assert.match((textPart as { text?: string }).text!, /Mercury it is/);
 		// The answered quiz part is still there, now with its output.
 		const answeredQuiz = finalParts.find((p) => p.type === "tool-quiz");
 		assert.ok(answeredQuiz && answeredQuiz.type === "tool-quiz" && (answeredQuiz as { state?: string }).state === "output-available");
+		// The graded answer rode the record as the call's tool result and
+		// round-trips through JSON (undefined keys drop) — compare its
+		// SUBSTANCE, not key-for-key against the in-memory build.
+		const out = (answeredQuiz as { output?: { questionId?: string; correct?: boolean } }).output!;
+		assert.equal(out.questionId, "call-1");
+		assert.equal(out.correct, true);
 
 		// The model actually received the graded answer as a tool result.
 		assert.equal(calls.length, 2, "model saw exactly two prompts");
@@ -243,14 +263,41 @@ describe("teacher chat flow (scripted model)", () => {
 		assert.ok(toolResultSent, "continuation prompt carries the tool result to the model");
 
 		// No pending question remains.
-		assert.equal(findPendingToolCall(saved2.messages), null);
+		assert.equal(danglingQuestionOf(saved2.messages), null);
 	});
 
 	it("rejects unknown chats", async () => {
-		const res = await handleChatRequest(post("chat_nonexistent", []));
+		const res = await handleChatRequest(post("chat_nonexistent", { type: "text", text: "hi" }));
 		assert.equal(res.status, 404);
 	});
 
+	it("refuses malformed inputs with a clean 400 — no liveness effects, no lockout", async () => {
+		const chat = createConfiguredChat("Test: malformed input");
+		createdChats.push(chat.id);
+
+		// A text event with no text: refused at the parse boundary.
+		const res = await handleChatRequest(post(chat.id, { type: "text" }), agentFactory(scriptedTeacher(defaultLesson).engine));
+		assert.equal(res.status, 400, "malformed input is a clean 400");
+		assert.equal(isTurnRunning(chat.id), false, "the refusal never registered a turn");
+
+		// An ANSWER with no dangling question call: the orphan-400 discipline
+		// (the server owns the record — it validates the target call).
+		const res2 = await handleChatRequest(
+			post(chat.id, { type: "answer", toolCallId: "call-none", answer: { correct: true } }),
+			agentFactory(scriptedTeacher(defaultLesson).engine),
+		);
+		assert.equal(res2.status, 400, "an answer with no pending question call is refused");
+		assert.equal(isTurnRunning(chat.id), false);
+
+		// And the chat is NOT locked: the next (valid) turn is accepted.
+		const ok = await handleChatRequest(
+			post(chat.id, { type: "text", text: "teach me" }),
+			agentFactory(scriptedTeacher(defaultLesson).engine),
+		);
+		assert.equal(ok.status, 200);
+		await drain(ok);
+	});
+
 	it("streams tool-input-start before tool-input-available (protocol pin for the 'Writing a question…' indicator)", async () => {
 		// The client's writing indicator keys off tool parts in state
 		// 'input-streaming', which the stream processor sets from the
@@ -259,8 +306,7 @@ describe("teacher chat flow (scripted model)", () => {
 		const { engine } = scriptedTeacher(defaultLesson);
 		const chat = createConfiguredChat("Test: protocol pin");
 		createdChats.push(chat.id);
-		const firstUser = { id: "u1", role: "user", parts: [{ type: "text", text: "quiz me" }] };
+		const body = await drain(await handleChatRequest(post(chat.id, { type: "text", text: "quiz me" }), agentFactory(engine)));
-		const body = await drain(await handleChatRequest(post(chat.id, [firstUser]), agentFactory(engine)));
 		const startIdx = body.indexOf('"type":"tool-input-start"');
 		const availIdx = body.indexOf('"type":"tool-input-available"');
 		assert.ok(startIdx !== -1, "tool-input-start chunk present in the stream");
@@ -275,8 +321,7 @@ describe("teacher chat flow (scripted model)", () => {
 		const chat = createConfiguredChat("Test: view cancel");
 		createdChats.push(chat.id);
 
-		const req = post(chat.id, [{ id: "u1", role: "user", parts: [{ type: "text", text: "hold my turn" }] }]);
+		const res = await handleChatRequest(post(chat.id, { type: "text", text: "hold my turn" }), agentFactory(engine));
-		const res = await handleChatRequest(req, agentFactory(engine));
 		assert.equal(res.status, 200);
 		// Read one chunk then cancel — the browser view leaves mid-stream.
 		const reader = res.body!.getReader();
@@ -297,7 +342,7 @@ describe("teacher chat flow (scripted model)", () => {
 	it("an ungradeable quiz is rejected at the call boundary, the error reaches the model, and the model retries", async () => {
 		// The authoring contract (question-core superRefine): a quiz whose
 		// correctAnswer matches no option value must NEVER reach the dock —
-		// toPiTool re-runs the zod schema at the call boundary, marks the
+		// the boundary re-runs the schema at the call boundary, marks the
 		// call invalid, and returns the validation error to the teacher as
 		// a tool result. The loop re-prompts the model, which retries in the
 		// same turn. This pins that whole mechanism (the live Nietzsche bug).
@@ -328,14 +373,12 @@ describe("teacher chat flow (scripted model)", () => {
 
 		const chat = createConfiguredChat("Test: bad quiz retry");
 		createdChats.push(chat.id);
-		const firstUser = { id: "u1", role: "user", parts: [{ type: "text", text: "quiz me" }] };
+		const body = await drain(await handleChatRequest(post(chat.id, { type: "text", text: "quiz me" }), agentFactory(engine)));
-		const body = await drain(await handleChatRequest(post(chat.id, [firstUser]), agentFactory(engine)));
 
 		// WIRE pin (the live modal-realism crash): the invalid call must NEVER
 		// become input-available — the dock mounts on input-available parts and
 		// crashed on a malformed quiz before tool-input-error could replace it.
-		// The SDK gated this with InvalidToolInputError; the bridge gates it on
+		// The boundary gates this on clean tool_execution_end.
-		// clean tool_execution_end.
 		assert.ok(
 			!body.includes('"type":"tool-input-available","toolCallId":"call-bad"'),
 			"the invalid call never reached input-available on the wire",
@@ -358,11 +401,12 @@ describe("teacher chat flow (scripted model)", () => {
 			"the validation error reached the model",
 		);
 
-		// The transcript: the failed call persisted as an error part (renders
+		// The transcript: the failed call persisted as an ERROR RESULT (the
-		// nothing client-side), the retry as the pending quiz.
+		// model's retry context — errored question calls DO persist), the
+		// retry as the dangling quiz. The projection renders the error part.
 		const saved = chatStore.getChat(chat.id)!;
-		const assistantMsg = saved.messages[1]!;
+		const view = projectNative(saved.messages);
-		const quizParts = assistantMsg.parts.filter((p) => p.type === "tool-quiz");
+		const quizParts = view[1]!.parts.filter((p) => p.type === "tool-quiz");
 		const failed = quizParts.find(
 			(p) => p.type === "tool-quiz" && (p as { state?: string }).state === "output-error",
 		);
@@ -371,7 +415,7 @@ describe("teacher chat flow (scripted model)", () => {
 			String((failed as { errorText?: string }).errorText),
 			/does not match any option value/,
 		);
-		const pending = findPendingToolCall(saved.messages);
+		const pending = danglingQuestionOf(saved.messages);
 		assert.equal(pending?.toolCallId, "call-good", "the RETRIED quiz is the pending one");
 		assert.deepEqual(pending?.input, QUIZ_INPUT);
 	});
@@ -400,8 +444,7 @@ describe("teacher chat flow (scripted model)", () => {
 
 		const chat = createConfiguredChat("Test: string options");
 		createdChats.push(chat.id);
-		const firstUser = { id: "u1", role: "user", parts: [{ type: "text", text: "quiz me" }] };
+		const body = await drain(await handleChatRequest(post(chat.id, { type: "text", text: "quiz me" }), agentFactory(engine)));
-		const body = await drain(await handleChatRequest(post(chat.id, [firstUser]), agentFactory(engine)));
 
 		assert.ok(
 				!body.includes('"type":"tool-input-available","toolCallId":"call-stringy"'),
@@ -413,12 +456,13 @@ describe("teacher chat flow (scripted model)", () => {
 			);
 
 		const saved = chatStore.getChat(chat.id)!;
-		const failed = saved.messages[1]!.parts.find(
+		const view = projectNative(saved.messages);
+		const failed = view[1]!.parts.find(
 				(p) => (p as { toolCallId?: string }).toolCallId === "call-stringy",
 			);
 		assert.equal((failed as { state?: string }).state, "output-error", "persisted as an error part");
 		assert.match(String((failed as { errorText?: string }).errorText), /options/);
-		const pending = findPendingToolCall(saved.messages);
+		const pending = danglingQuestionOf(saved.messages);
 		assert.equal(pending?.toolCallId, "call-clean", "the retried quiz is the pending one");
 	});
 
@@ -426,8 +470,8 @@ describe("teacher chat flow (scripted model)", () => {
 		// The live modal-realism observation: the teacher batched two quizzes
 		// in one turn, and the dock showed the SECOND one first (the backward
 		// part scan), so the interaction order was reversed vs the record.
-		// Pins: (A) findPendingToolCall picks the FIRST unanswered question in
+		// Pins: (A) danglingQuestionOf picks the FIRST unanswered question in
-		// part order; (B) question tools execute sequentially, so their
+		// call order; (B) question tools execute sequentially, so their
 		// tool-input-available chunks arrive in call order on the wire.
 		const QUIZ_A = { ...QUIZ_INPUT, question: "Quiz A: which planet is closest to the sun?" };
 		const QUIZ_B = { ...QUIZ_INPUT, question: "Quiz B: which planet is largest?" };
@@ -442,8 +486,7 @@ describe("teacher chat flow (scripted model)", () => {
 
 		const chat = createConfiguredChat("Test: parallel quizzes");
 		createdChats.push(chat.id);
-		const firstUser = { id: "u1", role: "user", parts: [{ type: "text", text: "quiz me twice" }] };
+		const body = await drain(await handleChatRequest(post(chat.id, { type: "text", text: "quiz me twice" }), agentFactory(engine)));
-		const body = await drain(await handleChatRequest(post(chat.id, [firstUser]), agentFactory(engine)));
 
 		// (B) wire determinism: the batches' input-available chunks in call order.
 		const availA = body.indexOf('"type":"tool-input-available","toolCallId":"call-a"');
@@ -451,30 +494,20 @@ describe("teacher chat flow (scripted model)", () => {
 		assert.ok(availA !== -1 && availB !== -1, "both quizzes became available");
 		assert.ok(availA < availB, "call A's input became available before call B's (sequential execution)");
 
-		// Saved in call order.
+		// Saved in call order (the projection preserves the content order).
 		const saved = chatStore.getChat(chat.id)!;
-		const quizIds = saved.messages[1]!.parts
+		const quizIds = projectNative(saved.messages)[1]!.parts
 			.filter((p) => p.type === "tool-quiz")
 			.map((p) => (p as { toolCallId: string }).toolCallId);
 		assert.deepEqual(quizIds, ["call-a", "call-b"], "parts persisted in call order");
 
 		// (A) the dock serializes answering in the same order: A first, then B.
-		const pending = findPendingToolCall(saved.messages);
+		const pending = danglingQuestionOf(saved.messages);
 		assert.equal(pending?.toolCallId, "call-a", "the FIRST asked question is the dock subject");
-		// …the learner answers A (client-side grading seam — state flip only here)…
+		// …the learner answers A: the answer lands as call-a's tool result —
-		const answered = saved.messages.map((m) =>
+		// the SECOND question becomes the dock subject only after that.
-			(m as { id?: string }).id === saved.messages[1]!.id
+		const answered = [...saved.messages, newAnswerResult("call-a", "quiz", gradedAnswer(QUIZ_A, ["Mercury"]))];
-				? {
+		const next = danglingQuestionOf(answered);
-						...m,
-						parts: (m as { parts: unknown[] }).parts.map((p) =>
-							(p as { toolCallId?: string }).toolCallId === "call-a"
-								? { ...(p as object), state: "output-available", output: { correct: true } }
-								: p,
-						),
-					}
-					: m,
-		);
-		const next = findPendingToolCall(answered as UIMessage[]);
 		assert.equal(next?.toolCallId, "call-b", "the SECOND question becomes the dock subject only after the first is answered");
 	});
 });
@@ -483,7 +516,7 @@ describe("chat store", () => {
 	it("round-trips and lists chats", async () => {
 		const chat = chatStore.createChat("Store test");
 		createdChats.push(chat.id);
-		chatStore.saveMessages(chat.id, [{ id: "m1", role: "user", parts: [{ type: "text", text: "hi" }] }]);
+		chatStore.saveMessages(chat.id, [{ id: "m1", role: "user", content: "hi", timestamp: 1 } as never]);
 		const loaded = chatStore.getChat(chat.id)!;
 		assert.equal(loaded.messages.length, 1);
 		assert.equal(loaded.title, "Store test");
@@ -510,18 +543,17 @@ describe("mid-turn navigation (turn liveness + write-ahead)", () => {
 		const chat = createConfiguredChat("Test: turn guard");
 		createdChats.push(chat.id);
 
-		const firstUser = { id: "u1", role: "user", parts: [{ type: "text", text: "teach me the solar system" }] };
+		const res1 = await handleChatRequest(post(chat.id, { type: "text", text: "teach me the solar system" }), agentFactory(engine)); // NOT drained → in flight
-		const res1 = await handleChatRequest(post(chat.id, [firstUser]), agentFactory(engine)); // NOT drained → in flight
 		assert.equal(isTurnRunning(chat.id), true, "turn registered as in flight");
 
 		// A stale client (remount racing a live turn) tries to start a second turn.
-		const res2 = await handleChatRequest(post(chat.id, [firstUser]), agentFactory(engine));
+		const res2 = await handleChatRequest(post(chat.id, { type: "text", text: "teach me the solar system" }), agentFactory(engine));
 		assert.equal(res2.status, 409, "concurrent turn rejected — last-writer-wins persist would clobber it");
 
 		await drain(res1); // finish → onFinish → endTurn
 		assert.equal(isTurnRunning(chat.id), false, "registry cleared at finish");
 
-		const res3 = await handleChatRequest(post(chat.id, [firstUser]), agentFactory(engine));
+		const res3 = await handleChatRequest(post(chat.id, { type: "text", text: "teach me the solar system" }), agentFactory(engine));
 		assert.equal(res3.status, 200, "the next turn is accepted after the previous finished");
 		await drain(res3);
 	});
@@ -531,69 +563,31 @@ describe("mid-turn navigation (turn liveness + write-ahead)", () => {
 		const chat = createConfiguredChat("Test: write-ahead");
 		createdChats.push(chat.id);
 
-		// Turn 1: the teacher asks the quiz (pending part in the record).
+		// Turn 1: the teacher asks the quiz (dangling call in the record).
-		const firstUser = { id: "u1", role: "user", parts: [{ type: "text", text: "teach me the solar system" }] };
+		await drain(await handleChatRequest(post(chat.id, { type: "text", text: "teach me the solar system" }), agentFactory(engine)));
-		await drain(await handleChatRequest(post(chat.id, [firstUser]), agentFactory(engine)));
-		const saved1 = chatStore.getChat(chat.id)!;
-		const assistantMsg = saved1.messages[1]!;
 
-		// The learner answers; the client posts the graded transcript back.
+		// The learner answers; the client posts the ANSWER EVENT.
-		const options = normalizeOptions(QUIZ_INPUT.options);
+		const answer = gradedAnswer(QUIZ_INPUT, ["Mercury"]);
-		const qd: QuestionData = {
-			id: "call-1",
-			kind: "quiz",
-			question: QUIZ_INPUT.question,
-			mode: "single-select",
-			options,
-			correctIndices: resolveCorrect(coerceCorrectAnswer(QUIZ_INPUT.correctAnswer), options).indices,
-			explanation: QUIZ_INPUT.explanation,
-			createdAt: new Date().toISOString(),
-		};
-		const answer = buildAnswer(qd, { values: ["Mercury"] });
-		const messages2 = saved1.messages.map((m) =>
-			m.id === assistantMsg.id
-				? {
-						...m,
-						parts: m.parts.map((p) =>
-							p.type === "tool-quiz" ? { ...p, state: "output-available" as const, output: answer } : p,
-						),
-					}
-				: m,
-		);
 
 		// NOT drained: the teacher turn is streaming, but the answer is already
 		// on disk — a remount (or crash) mid-turn sees the answered quiz, never
 		// the stale pre-answer question.
-		const res = await handleChatRequest(post(chat.id, messages2), agentFactory(engine));
+		const res = await handleChatRequest(post(chat.id, { type: "answer", toolCallId: "call-1", answer }), agentFactory(engine));
 		const midTurn = chatStore.getChat(chat.id)!;
-		const midQuiz = midTurn.messages[1]!.parts.find((p) => p.type === "tool-quiz");
+		assert.equal(midTurn.messages.length, 3, "write-ahead appended the answer tool result before finish");
+		assert.equal((midTurn.messages[2] as { role?: string }).role, "toolResult");
+		const midQuiz = projectNative(midTurn.messages)[1]!.parts.find((p) => p.type === "tool-quiz");
 		assert.ok(midQuiz && midQuiz.type === "tool-quiz");
 		assert.equal((midQuiz as { state?: string }).state, "output-available", "write-ahead persisted the answer before finish");
 
 		await drain(res); // finish → persist the full turn → endTurn
 		const saved2 = chatStore.getChat(chat.id)!;
-		assert.equal(saved2.messages.length, 2, "full turn persisted as usual at finish");
+		// Native: user, assistant, answer result, reaction — one append-only
+		// history; the projection still renders ONE assistant group.
+		assert.equal(saved2.messages.length, 4, "full turn persisted as usual at finish");
+		assert.equal(projectNative(saved2.messages).length, 2, "the projection groups the answered quiz + reaction");
 		assert.equal(isTurnRunning(chat.id), false, "registry cleared at finish");
 	});
-
-	it("a turn that fails to start (malformed messages) clears the registry — no lockout", async () => {
-		const chat = createConfiguredChat("Test: turn failed to start");
-		createdChats.push(chat.id);
-		// A text part with no text: fails message validation before the stream
-		// exists — the path where no onFinish will ever run.
-		const bad = [{ id: "m1", role: "user", parts: [{ type: "text" }] }];
-		const res = await handleChatRequest(post(chat.id, bad), agentFactory(scriptedTeacher(defaultLesson).engine));
-		assert.equal(res.status, 500, "turn-start failure is a 500, not a hang");
-		assert.equal(isTurnRunning(chat.id), false, "registry cleared when the stream never started");
-
-		// And the chat is NOT locked: the next (valid) turn is accepted.
-		const ok = await handleChatRequest(
-			post(chat.id, [{ id: "m1", role: "user", parts: [{ type: "text", text: "teach me" }] }]),
-			agentFactory(scriptedTeacher(defaultLesson).engine),
-		);
-		assert.equal(ok.status, 200);
-		await drain(ok);
-	});
 });
 
 describe("renameChat (the header's click-to-edit title)", () => {
@@ -635,8 +629,7 @@ describe("the BYOK turn gate (no factory floor — owner, 2026-09-22)", () => {
 		// slot legitimately opens the gate (the chain is honest both ways).
 		const expectRefusal = effectiveSettings().models.strong === null;
 
-		const firstUser = { id: "u1", role: "user", parts: [{ type: "text", text: "teach me the solar system" }] };
+		const res = await handleChatRequest(post(chat.id, { type: "text", text: "teach me the solar system" }), agentFactory(scriptedTeacher(defaultLesson).engine));
-		const res = await handleChatRequest(post(chat.id, [firstUser]), agentFactory(scriptedTeacher(defaultLesson).engine));
 
 		if (expectRefusal) {
 			assert.equal(res.status, 503, "the universal turn gate refuses before beginTurn");
@@ -660,8 +653,7 @@ describe("the BYOK turn gate (no factory floor — owner, 2026-09-22)", () => {
 	it("a per-chat model alone opens the gate (the setup flow's exact write)", async () => {
 		const chat = createConfiguredChat("Test: per-chat pin only");
 		createdChats.push(chat.id);
-		const firstUser = { id: "u1", role: "user", parts: [{ type: "text", text: "teach me the solar system" }] };
+		const res = await handleChatRequest(post(chat.id, { type: "text", text: "teach me the solar system" }), agentFactory(scriptedTeacher(defaultLesson).engine));
-		const res = await handleChatRequest(post(chat.id, [firstUser]), agentFactory(scriptedTeacher(defaultLesson).engine));
 		assert.equal(res.status, 200, "chat.settings.model satisfies the chain without any record slot");
 		await drain(res);
 	});
@@ -683,8 +675,7 @@ describe("the key-presence turn gate (provider-key interlude, 2026-09-25)", () =
 			// chain the strong slot rides. The gate fires BEFORE the engine
 			// build, so the fake model id never hits the catalog.
 			chatStore.saveSettings(chat.id, { model: { provider: "together", id: "no-such-model" } });
-			const firstUser = { id: "u1", role: "user", parts: [{ type: "text", text: "teach me something" }] };
+			const res = await handleChatRequest(post(chat.id, { type: "text", text: "teach me something" }), agentFactory(scriptedTeacher(defaultLesson).engine));
-			const res = await handleChatRequest(post(chat.id, [firstUser]), agentFactory(scriptedTeacher(defaultLesson).engine));
 
 			assert.equal(res.status, 503, "the key-presence gate refuses before beginTurn");
 			const body = (await res.json()) as { error: string; code: string; provider: string; slots: string[] };
@@ -708,8 +699,7 @@ describe("the key-presence turn gate (provider-key interlude, 2026-09-25)", () =
 			// A REAL catalog model: the engine build AFTER the gate must
 			// resolve — the injected agent replaces the loop, not the build.
 			chatStore.saveSettings(chat.id, { model: { provider: "openai", id: "gpt-4" } });
-			const firstUser = { id: "u1", role: "user", parts: [{ type: "text", text: "teach me something" }] };
+			const res = await handleChatRequest(post(chat.id, { type: "text", text: "teach me something" }), agentFactory(scriptedTeacher(defaultLesson).engine));
-			const res = await handleChatRequest(post(chat.id, [firstUser]), agentFactory(scriptedTeacher(defaultLesson).engine));
 
 			assert.equal(res.status, 200, "the env-shadowed key counts as present — the turn runs");
 			await drain(res);
@@ -728,8 +718,7 @@ describe("background-turn runner (owner ruling 2026-09-25: every turn is a serve
 		const chat = createConfiguredChat("Test: reattach replay");
 		createdChats.push(chat.id);
 
-		const req = post(chat.id, [{ id: "u1", role: "user", parts: [{ type: "text", text: "hold my turn" }] }]);
+		const first = await handleChatRequest(post(chat.id, { type: "text", text: "hold my turn" }), agentFactory(engine));
-		const first = await handleChatRequest(req, agentFactory(engine));
 		assert.equal(first.status, 200);
 		// Consume the first view a little (the start chunk is out).
 		const reader = first.body!.getReader();
@@ -768,8 +757,7 @@ describe("background-turn runner (owner ruling 2026-09-25: every turn is a serve
 		const chat = createConfiguredChat("Test: remote abort");
 		createdChats.push(chat.id);
 
-		const req = post(chat.id, [{ id: "u1", role: "user", parts: [{ type: "text", text: "wait forever" }] }]);
+		const res = await handleChatRequest(post(chat.id, { type: "text", text: "wait forever" }), agentFactory(engine));
-		const res = await handleChatRequest(req, agentFactory(engine));
 		assert.equal(res.status, 200);
 		assert.ok(runningTurn(chat.id), "turn registered while in flight");
 		const viewText = res.text(); // the first view, reading to settle
@@ -802,8 +790,7 @@ describe("background-turn runner (owner ruling 2026-09-25: every turn is a serve
 
 		// And after a settled turn, the registry is empty — the GET would
 		// serve the same terminal, not a stale handle.
-		const req = post(chat.id, [{ id: "u1", role: "user", parts: [{ type: "text", text: "quiz me" }] }]);
+		await drain(await handleChatRequest(post(chat.id, { type: "text", text: "quiz me" }), agentFactory(engine)));
-		await drain(await handleChatRequest(req, agentFactory(engine)));
 		assert.equal(runningTurn(chat.id), undefined, "no handle survives settle");
 	});
 
@@ -819,8 +806,7 @@ describe("background-turn runner (owner ruling 2026-09-25: every turn is a serve
 
 		const views = new Map<string, Promise<string>>();
 		for (const { chat, engine } of chats) {
-			const req = post(chat.id, [{ id: "u1", role: "user", parts: [{ type: "text", text: "hold my turn" }] }]);
+			const res = await handleChatRequest(post(chat.id, { type: "text", text: "hold my turn" }), agentFactory(engine));
-			const res = await handleChatRequest(req, agentFactory(engine));
 			assert.equal(res.status, 200);
 			const handle = runningTurn(chat.id)!;
 			assert.ok(handle, `chat ${chat.id} has its own handle`);

tests/chat-transport.test.ts

@@ -1,25 +1,20 @@
 /**
- * 409 merge-retry transport tests (components/chat-transport.ts).
+ * 409 identity-retry transport tests (components/chat-transport.ts).
  *
- * Every 409 means the server record is AHEAD (a wake turn persisted the
+ * Wave B (input events): a 409 means a turn is in flight — the event was
- * steer): the retry must wait out the turn, merge the outgoing messages onto
+ * NEVER persisted (write-ahead happens only on accept), so the retry waits
- * the fresh record, and re-POST the merged list — a bare retry would clobber
+ * out the turn and re-POSTs the SAME event body. Nothing merges, nothing
- * the steer/wake messages via the write-ahead persist.
+ * derives: the event is the unit, and re-POSTing it is idempotent-safe.
  */
 import assert from "node:assert/strict";
 import { afterEach, describe, it } from "node:test";
 import { retryingFetch } from "../components/chat-transport.ts";
-import type { TeacherUIMessage } from "../src/core/ui-message.ts";
 
 const realFetch = globalThis.fetch;
 afterEach(() => {
 	globalThis.fetch = realFetch;
 });
 
-function msg(id: string, role: "user" | "assistant", text: string): TeacherUIMessage {
-	return { id, role, metadata: {}, parts: [{ type: "text", text }] };
-}
-
 interface Call {
 	url: string;
 	body: string | undefined;
@@ -30,8 +25,6 @@ function installFetch(routes: {
 	chatPOST: (call: Call, attempt: number) => Response;
 	/** GET /api/jobs?chatId=… → turnInFlight value per poll (poll index). */
 	jobsGET?: (poll: number) => boolean;
-	/** GET /api/chats/<id> → messages array. */
-	chatGET?: () => TeacherUIMessage[];
 }): Call[] {
 	const calls: Call[] = [];
 	let poll = 0;
@@ -42,14 +35,14 @@ function installFetch(routes: {
 			return routes.chatPOST(calls.at(-1)!, calls.filter((c) => c.url === "/api/chat").length);
 		}
 		if (url.startsWith("/api/jobs")) return Response.json({ turnInFlight: routes.jobsGET?.(++poll) ?? false });
-		if (url.startsWith("/api/chats/")) return Response.json({ messages: routes.chatGET?.() ?? [] });
 		throw new Error(`unexpected fetch: ${url}`);
 	}) as typeof globalThis.fetch;
 	return calls;
 }
 
-function outgoing(clientOnly: TeacherUIMessage[]): string {
+/** One input event — the POST body's whole unit. */
-	return JSON.stringify({ chatId: "chat_x", messages: [...clientOnly] });
+function outgoing(input: Record<string, unknown>): string {
+	return JSON.stringify({ chatId: "chat_x", input });
 }
 
 describe("retryingFetch (409 merge-retry)", { skip: process.env.NO_SLOW ? true : undefined }, () => {
@@ -58,66 +51,54 @@ describe("retryingFetch (409 merge-retry)", { skip: process.env.NO_SLOW ? true :
 			chatPOST: () => new Response("stream", { status: 200 }),
 		});
 		const fetch = retryingFetch("chat_x", { pollMs: 10, waitMaxMs: 100 });
-		const res = await fetch("/api/chat", { method: "POST", body: outgoing([msg("c1", "user", "hi")]) });
+		const res = await fetch("/api/chat", { method: "POST", body: outgoing({ type: "text", text: "hi" }) });
 		assert.equal(res.status, 200);
 		assert.equal(calls.length, 1, "no polling, no merge, single call");
 	});
 
-	it("waits out the turn, merges onto the fresh record, re-POSTs the merged list", async () => {
+	it("waits out the turn, then re-POSTs the SAME event body (identity retry)", async () => {
-		const server = [msg("steer_1", "user", "Research complete"), msg("s1", "assistant", "wake turn")];
+		const event = { type: "text", text: "my question while the wake turn ran" };
-		const fresh = [msg("c1", "user", "my question while the wake turn ran")];
 		const calls = installFetch({
 			chatPOST: (_call, n) => (n === 1 ? new Response("busy", { status: 409 }) : new Response("stream", { status: 200 })),
 			jobsGET: (poll) => poll <= 1, // first poll: still running; second: done
-			chatGET: () => server,
 		});
 		const fetch = retryingFetch("chat_x", { pollMs: 10, waitMaxMs: 100 });
-		const res = await fetch("/api/chat", { method: "POST", body: outgoing(fresh) });
+		const res = await fetch("/api/chat", { method: "POST", body: outgoing(event) });
 		assert.equal(res.status, 200);
 
-		// second POST carries server truth + the client's unsent message, in order
+		// The retry carries the IDENTICAL body — the event was never
-		const retry = JSON.parse(calls.filter((c) => c.url === "/api/chat")[1]!.body!);
+		// persisted pre-accept, so re-sending it is the whole protocol.
-		assert.deepEqual(
+		const posts = calls.filter((c) => c.url === "/api/chat");
-			retry.messages.map((m: { id: string }) => m.id),
+		assert.equal(posts.length, 2, "one 409, one retry");
-			["steer_1", "s1", "c1"],
+		assert.equal(posts[1]!.body, posts[0]!.body, "the event body is byte-identical");
-		);
+		assert.deepEqual(JSON.parse(posts[1]!.body!), { chatId: "chat_x", input: event });
 	});
 
-	it("drops client messages the server already has (no duplicates in the merge)", async () => {
+	it("does not poll the record or merge — the event is the only payload", async () => {
-		const server = [msg("steer_1", "user", "Research complete"), msg("c1", "user", "my question")];
 		const calls = installFetch({
 			chatPOST: (_call, n) => (n === 1 ? new Response("busy", { status: 409 }) : new Response("stream", { status: 200 })),
-			chatGET: () => server,
 		});
 		const fetch = retryingFetch("chat_x", { pollMs: 10, waitMaxMs: 100 });
-		const res = await fetch("/api/chat", {
+		const res = await fetch("/api/chat", { method: "POST", body: outgoing({ type: "text", text: "q" }) });
-			method: "POST",
-			body: outgoing([msg("steer_1", "user", "Research complete"), msg("c1", "user", "my question")]),
-		});
 		assert.equal(res.status, 200);
-		const retry = JSON.parse(calls.filter((c) => c.url === "/api/chat")[1]!.body!);
+		assert.equal(
-		assert.deepEqual(
+			calls.filter((c) => c.url.startsWith("/api/chats/")).length,
-			retry.messages.map((m: { id: string }) => m.id),
+			0,
-			["steer_1", "c1"],
+			"the retry never reads the record — the server owns it",
 		);
 	});
 
-	it("loops on repeated 409s, re-merging fresh each time", async () => {
+	it("loops on repeated 409s, re-POSTing the same event each time", async () => {
-		const server = [msg("steer_1", "user", "Research complete")];
+		const event = { type: "answer", toolCallId: "call-1", answer: { correct: true } };
 		const calls = installFetch({
 			chatPOST: (_call, n) => (n <= 2 ? new Response("busy", { status: 409 }) : new Response("stream", { status: 200 })),
-			chatGET: () => server,
 		});
 		const fetch = retryingFetch("chat_x", { pollMs: 10, waitMaxMs: 100 });
-		const res = await fetch("/api/chat", { method: "POST", body: outgoing([msg("c1", "user", "q")]) });
+		const res = await fetch("/api/chat", { method: "POST", body: outgoing(event) });
 		assert.equal(res.status, 200);
 		const posts = calls.filter((c) => c.url === "/api/chat");
 		assert.equal(posts.length, 3);
-		const last = JSON.parse(posts[2]!.body!);
+		assert.ok(posts.every((c) => c.body === posts[0]!.body), "every attempt carries the same event");
-		assert.deepEqual(
-			last.messages.map((m: { id: string }) => m.id),
-			["steer_1", "c1"],
-		);
 	});
 
 	it("gives up after TURN_WAIT_MAX_MS and returns the last 409 (banner as before)", async () => {
@@ -129,7 +110,7 @@ describe("retryingFetch (409 merge-retry)", { skip: process.env.NO_SLOW ? true :
 			jobsGET: () => true,
 		});
 		const fetch = retryingFetch("chat_x", { pollMs: 10, waitMaxMs: 100 });
-		const res = await fetch("/api/chat", { method: "POST", body: outgoing([msg("c1", "user", "q")]) });
+		const res = await fetch("/api/chat", { method: "POST", body: outgoing({ type: "text", text: "q" }) });
 		assert.equal(res.status, 409);
 		polls = calls.filter((c) => c.url.startsWith("/api/jobs")).length;
 		assert.ok(polls <= 15, `expected bounded polling (~10×10ms), got ${polls}`);

tests/demos.test.tsx

@@ -50,16 +50,15 @@ import { runDemoBuilder } from "../src/agent/subagents/demo-builder.ts";
 import { headlessOverride, type DemoRunResult, type HeadlessApi } from "../src/agent/subagents/headless.ts";
 import { createJobRunner, demoModelOverride, visualModelOverride } from "../src/agent/subagents/runner.ts";
 import { runVisualMaker } from "../src/agent/subagents/visual-maker.ts";
-import { buildAbortSteer, buildSubagentSteer, isSubagentFailure, type SubagentSteerMessage } from "../src/core/contracts.ts";
+import { buildAbortSteer, buildSubagentSteer, isSubagentFailure, type SteerMessage } from "../src/core/contracts.ts";
 import type { JobRecord } from "../src/core/contracts.ts";
 import { createTeacherTools } from "../src/agent/tools.ts";
 import { chatStore } from "../src/store/chats.ts";
 import { jobStore } from "../src/store/jobs.ts";
 import { handleChatRequest } from "../src/server/chat-handler.ts";
-import { createTeacherAgent, type TeachingAgent } from "../src/agent/teacher-agent.ts";
+import { createTeacherAgent } from "../src/agent/teacher-agent.ts";
-import { recordToPiMessages } from "../src/server/pi/record-adapter.ts";
+import { projectNative } from "../src/core/projection.ts";
 import type { PiEngine } from "../src/agent/models.ts";
-import type { UIMessage } from "ai";
 
 /**
  * A fake deliver seam + a runner wired like the chat-handler's, per test:
@@ -67,13 +66,13 @@ import type { UIMessage } from "ai";
  * record reads exactly as production does after the wake turn completes.
  */
 function testRunner() {
-	const steers: SubagentSteerMessage[] = [];
+	const steers: SteerMessage[] = [];
 	const runner = createJobRunner({
 		chatStore,
 		jobStore,
 		deliver: async (steer) => {
 			steers.push(steer);
-			const jobId = steer.metadata.subagentResult.jobId;
+			const jobId = (steer.details as { jobId: string }).jobId;
 			const job = jobStore.getJob(jobId);
 			if (job && job.status === "running") {
 				const failed = job.result ? isSubagentFailure(job.kind, job.result as never) : true;
@@ -349,7 +348,7 @@ describe("steer card rendering (the delivered artifact)", () => {
 			{ id: "jd", kind: "demo", toolCallId: "cd" },
 			{ title: "Damped oscillator", html: DEMO_HTML, tested: true },
 		);
-		const html = renderToStaticMarkup(<SubagentSteerCard message={steer as never} />);
+		const html = renderToStaticMarkup(<SubagentSteerCard message={projectNative([steer])[0] as never} />);
 		assert.match(html, /sandbox="allow-scripts"/);
 		assert.ok(!html.includes("allow-same-origin"), "never allow-same-origin");
 		assert.match(html, /demo-resize/);
@@ -365,7 +364,7 @@ describe("steer card rendering (the delivered artifact)", () => {
 			{ id: "jd", kind: "demo", toolCallId: "cd" },
 			{ title: "T", html: "", tested: true, notes: "FAILED: never passed verification" },
 		);
-		const html = renderToStaticMarkup(<SubagentSteerCard message={steer as never} />);
+		const html = renderToStaticMarkup(<SubagentSteerCard message={projectNative([steer])[0] as never} />);
 		assert.match(html, /FAILED: never passed verification/);
 		assert.ok(!html.includes("<iframe"), "no iframe for a failed build");
 	});
@@ -376,7 +375,7 @@ describe("steer card rendering (the delivered artifact)", () => {
 			{ id: "jv", kind: "visual", toolCallId: "cv" },
 			{ svg, notes: "Looking at the render, the diagram is clean and accurate." },
 		);
-		const html = renderToStaticMarkup(<SubagentSteerCard message={steer as never} />);
+		const html = renderToStaticMarkup(<SubagentSteerCard message={projectNative([steer])[0] as never} />);
 		assert.ok(html.includes("circle"), "svg content rendered inline");
 		assert.match(html, /Figure/);
 		assert.match(html, /svg\]:w-full/, "svg scales to the display area's full width");
@@ -385,16 +384,19 @@ describe("steer card rendering (the delivered artifact)", () => {
 
 	it("renders the abort chip for an aborted job's steer (2026-09 dock semantics; the message type is the marker PART)", () => {
 		const steer = buildAbortSteer({ id: "jc", kind: "research", toolCallId: "cc" });
-		assert.equal(steer.metadata.subagentResult.aborted, true);
+		// Wave B: the steer is a native marker — the card renders its
-		assert.equal(steer.parts.length, 2, "text (teacher-facing) + the data-subagent-aborted marker part");
+		// PROJECTION (the same view the transcript renderer hands it).
-		const html = renderToStaticMarkup(<SubagentSteerCard message={steer as never} />);
+		const view = projectNative([steer])[0]!;
+		assert.equal((steer.details as { aborted: boolean }).aborted, true);
+		assert.equal(view.parts.length, 2, "text (teacher-facing) + the data-subagent-aborted marker part");
+		const html = renderToStaticMarkup(<SubagentSteerCard message={view as never} />);
 		assert.match(html, /job-aborted-badge/);
 		assert.match(html, /research/, "the job's kind, lower-cased like the complete-badge idiom");
 		assert.match(html, /aborted by the learner/);
 		// the teacher-facing protocol text never renders for the learner
 		assert.ok(!html.includes("no brief is coming"), "no protocol glue in the chip");
 		// the badge renders off the PART, not metadata (the custom-message scheme)
-		const noMeta = { ...steer, metadata: {} } as typeof steer;
+		const noMeta = { ...view, metadata: {} };
 		const htmlNoMeta = renderToStaticMarkup(<SubagentSteerCard message={noMeta as never} />);
 		assert.match(htmlNoMeta, /job-aborted-badge/, "metadata is pump mechanics, never the render seam");
 	});
@@ -410,7 +412,7 @@ describe("steer card rendering (the delivered artifact)", () => {
 				],
 			},
 		);
-		const html = renderToStaticMarkup(<SubagentSteerCard message={steer as never} />);
+		const html = renderToStaticMarkup(<SubagentSteerCard message={projectNative([steer])[0] as never} />);
 		assert.match(html, /Research/);
 		assert.match(html, /complete/);
 		assert.match(html, /2 sources/);
@@ -435,7 +437,7 @@ describe("steer card rendering (the delivered artifact)", () => {
 				pagesConsulted: [1, 2],
 			},
 		);
-		const html = renderToStaticMarkup(<SubagentSteerCard message={steer as never} />);
+		const html = renderToStaticMarkup(<SubagentSteerCard message={projectNative([steer])[0] as never} />);
 		assert.match(html, /PDF/);
 		assert.match(html, /reading complete/);
 		assert.match(html, /read 1 page/, "the badge counts READ pages, not search hits");
@@ -451,7 +453,7 @@ describe("steer card rendering (the delivered artifact)", () => {
 			{ id: "jpf2", kind: "pdf", toolCallId: "cpf2" },
 			{ path: "/tmp/doc.pdf", question: "q", brief: "PDF failed: the file could not be opened", pagesRead: [], pagesConsulted: [] },
 		);
-		const html = renderToStaticMarkup(<SubagentSteerCard message={steer as never} />);
+		const html = renderToStaticMarkup(<SubagentSteerCard message={projectNative([steer])[0] as never} />);
 		assert.match(html, /pdf-brief-card/);
 		assert.match(html, /failed/);
 		assert.match(html, /could not be opened/);
@@ -460,7 +462,7 @@ describe("steer card rendering (the delivered artifact)", () => {
 
 	it("renders the visual failure note with no svg when the build FAILED", () => {
 		const steer = buildSubagentSteer({ id: "jv", kind: "visual", toolCallId: "cv" }, { svg: "", notes: "FAILED: iteration limit" });
-		const html = renderToStaticMarkup(<SubagentSteerCard message={steer as never} />);
+		const html = renderToStaticMarkup(<SubagentSteerCard message={projectNative([steer])[0] as never} />);
 		assert.match(html, /FAILED: iteration limit/);
 		assert.ok(!html.includes("circle") && !html.includes("<svg"), "no svg for a failed build");
 	});
@@ -675,14 +677,32 @@ describe("demo/visual job runners", () => {
 	it("runJob completes a demo: result on the job, steer via deliver, ack stays on the part", async () => {
 		const chat = chatStore.createChat("Test: demo runner");
 		createdChats.push(chat.id);
+		// Wave B: a NATIVE fixture (the record holds agent history) — the
+		// runner's transcript scan reads it through the projection.
 		chatStore.saveMessages(chat.id, [
-			{ id: "u1", role: "user", parts: [{ type: "text", text: "show me compounding" }] },
+			{ id: "u1", role: "user", content: "show me compounding", timestamp: 1 } as never,
 			{
 				id: "a1",
 				role: "assistant",
-				parts: [{ type: "tool-demo", toolCallId: "call-d1", state: "output-available", input: DEMO_INPUT, output: "Dispatched." }],
+				content: [{ type: "toolCall", id: "call-d1", name: "demo", arguments: DEMO_INPUT as never }],
-			},
+				api: "openai-completions",
-		] as never);
+				provider: "openrouter",
+				model: "test",
+				usage: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+				stopReason: "stop",
+				timestamp: 1,
+			} as never,
+			{
+				id: "r1",
+				role: "toolResult",
+				toolCallId: "call-d1",
+				toolName: "demo",
+				content: [{ type: "text", text: "Dispatched." }],
+				details: "Dispatched.",
+				isError: false,
+				timestamp: 1,
+			} as never,
+		]);
 
 		const job = jobStore.createJob({ kind: "demo", chatId: chat.id, toolCallId: "call-d1" });
 		createdJobs.push(job.id);
@@ -712,15 +732,14 @@ describe("demo/visual job runners", () => {
 
 		// The steer carries the artifact for the renderer.
 		assert.equal(steers.length, 1, "exactly one steer");
-		const data = steers[0]!.parts[1];
+		const data = steers[0]!.details as { kind: string; result: unknown };
-		assert.ok(data.type === "data-subagent-artifact");
+		assert.equal(data.kind, "demo");
-		assert.equal(data.data.kind, "demo");
+		assert.deepEqual(data.result, result);
-		assert.deepEqual(data.data.result, result);
 
 		// The tool part keeps the DISPATCH ACK forever — the result never
 		// rewrites it (the teacher gets the result once, via the steer).
-		const saved = chatStore.getChat(chat.id)!;
+		const saved = projectNative(chatStore.getChat(chat.id)!.messages);
-		const part = saved.messages[1]!.parts.find((p) => p.type === "tool-demo");
+		const part = saved[1]!.parts.find((p) => p.type === "tool-demo");
 		assert.ok(part && part.type === "tool-demo", "demo tool part persisted");
 		assert.equal(typeof (part as { output?: unknown }).output, "string", "part output is the ack, not the result");
 	});
@@ -729,13 +748,29 @@ describe("demo/visual job runners", () => {
 		const chat = chatStore.createChat("Test: visual runner failure");
 		createdChats.push(chat.id);
 		chatStore.saveMessages(chat.id, [
-			{ id: "u1", role: "user", parts: [{ type: "text", text: "draw it" }] },
+			{ id: "u1", role: "user", content: "draw it", timestamp: 1 } as never,
 			{
 				id: "a1",
 				role: "assistant",
-				parts: [{ type: "tool-visual", toolCallId: "call-v1", state: "output-available", input: { brief: "b" }, output: "Dispatched." }],
+				content: [{ type: "toolCall", id: "call-v1", name: "visual", arguments: { brief: "b" } as never }],
-			},
+				api: "openai-completions",
-		] as never);
+				provider: "openrouter",
+				model: "test",
+				usage: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+				stopReason: "stop",
+				timestamp: 1,
+			} as never,
+			{
+				id: "r1",
+				role: "toolResult",
+				toolCallId: "call-v1",
+				toolName: "visual",
+				content: [{ type: "text", text: "Dispatched." }],
+				details: "Dispatched.",
+				isError: false,
+				timestamp: 1,
+			} as never,
+		]);
 
 		const job = jobStore.createJob({ kind: "visual", chatId: chat.id, toolCallId: "call-v1" });
 		createdJobs.push(job.id);
@@ -753,9 +788,7 @@ describe("demo/visual job runners", () => {
 		assert.match(errored.error ?? "", /never wrote an SVG/);
 
 		assert.ok(steers[0], "failure still delivers a steer — the teacher learns the outcome");
-		const data = steers[0]!.parts[1];
+		const result = (steers[0]!.details as { result: unknown }).result as { svg: string; notes?: string };
-		assert.ok(data.type === "data-subagent-artifact");
-		const result = data.data.result as { svg: string; notes?: string };
 		assert.equal(result.svg, "");
 		assert.match(result.notes ?? "", /^FAILED:/);
 	});
@@ -791,13 +824,18 @@ describe("demo/visual job runners", () => {
 						headers: { "Content-Type": "application/json" },
 						body: JSON.stringify({
 							chatId: chat.id,
-							messages: [{ id: "u1", role: "user", parts: [{ type: "text", text: "teach me compounding" }] }],
+							// Wave B: the input-events contract — one event,
+							// never a client transcript.
+							input: { type: "text", text: "teach me compounding" },
 						}),
 					}),
-					(outgoing: UIMessage[]): TeachingAgent =>
+					// The handler hands the factory the native build options
+					// (messages are the merged record; the record IS the agent
+					// state — no adapter conversion).
+					(opts) =>
 						createTeacherAgent(undefined, {
 							engine: teacher,
-							messages: recordToPiMessages(outgoing),
+							messages: opts.messages,
 							tools: createTeacherTools({
 								chatId: chat.id,
 								chatStore,
@@ -818,14 +856,14 @@ describe("demo/visual job runners", () => {
 			const done = jobStore.getJob(job!.id)!;
 			assert.equal(done.status, "done");
 
-			const saved = chatStore.getChat(chat.id)!;
+			const saved = projectNative(chatStore.getChat(chat.id)!.messages);
-			const part = saved.messages[1]!.parts.find((p) => p.type === "tool-demo");
+			const part = saved[1]!.parts.find((p) => p.type === "tool-demo");
 			assert.ok(part && part.type === "tool-demo", "demo tool part persisted");
 			assert.equal(part.state, "output-available", "the part resolved with the ack at dispatch time");
 			assert.match(String((part as { output?: unknown }).output), /fire-and-forget/);
 
 			assert.equal(steers.length, 1, "one job, one steer");
-			assert.equal(steers[0]!.metadata.subagentResult.jobId, job!.id);
+			assert.equal((steers[0]!.details as { jobId: string }).jobId, job!.id);
 
 			// Idempotency: dispatch dedupes by toolCallId — no second job.
 			assert.equal(jobStore.listJobs(chat.id).length, 1, "no duplicate job for the same tool part");

tests/extraction.test.ts

@@ -23,8 +23,10 @@ import assert from "node:assert/strict";
 import * as fs from "node:fs";
 import { after, describe, it } from "node:test";
 import { createFauxCore, fauxAssistantMessage, fauxToolCall, type FauxResponseStep } from "@earendil-works/pi-ai";
-import type { UIMessage } from "ai";
 import type { PiEngine } from "../src/agent/models.ts";
+import type { LhMessage } from "../src/core/native-messages.ts";
+import { newPlanBlockMessage } from "../src/core/native-messages.ts";
+import { projectNative } from "../src/core/projection.ts";
 import type {
 	AuditResult,
 	CoverageEntry,
@@ -116,26 +118,67 @@ function memoryLedgers() {
 	} satisfies GraphStore;
 }
 
-function assistant(id: string, parts: unknown[]): UIMessage {
+// Native fixture builders (Wave B): the record holds pi-native history —
-	return { id, role: "assistant", parts } as unknown as UIMessage;
+// an assistant message with its tool calls + one result message per call;
+// the projection reproduces the part shapes these view tests pin.
+interface NativeCallDesc {
+	name: string;
+	toolCallId: string;
+	input: Record<string, unknown>;
+	output: unknown;
 }
 
-function user(id: string, text: string): UIMessage {
+function user(id: string, text: string): LhMessage {
-	return { id, role: "user", parts: [{ type: "text", text }] } as unknown as UIMessage;
+	return { id, role: "user", content: text, timestamp: Date.now() } as never;
 }
 
-function quizPart(toolCallId: string, input: Record<string, unknown>, output: Record<string, unknown>): unknown {
+function assistant(id: string, items: unknown[]): LhMessage[] {
-	return { type: "tool-quiz", toolCallId, state: "output-available", input, output };
+	const content: unknown[] = [];
+	const calls: NativeCallDesc[] = [];
+	for (const item of items) {
+		const it = item as { type?: string; text?: string };
+		if (it && it.type === "text") {
+			content.push({ type: "text", text: it.text });
+		} else {
+			const call = item as NativeCallDesc;
+			calls.push(call);
+			content.push({ type: "toolCall", id: call.toolCallId, name: call.name, arguments: call.input as never });
+		}
+	}
+	const out: LhMessage[] = [
+		{
+			id,
+			role: "assistant",
+			content,
+			api: "openai-completions",
+			provider: "openrouter",
+			model: "test",
+			usage: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+			stopReason: "stop",
+			timestamp: Date.now(),
+		} as never,
+	];
+	for (const call of calls) {
+		out.push({
+			id: `r_${call.toolCallId}`,
+			role: "toolResult",
+			toolCallId: call.toolCallId,
+			toolName: call.name,
+			content: [{ type: "text", text: "ok" }],
+			details: call.output,
+			isError: false,
+			timestamp: Date.now(),
+		} as never);
+	}
+	return out;
 }
 
-function planPart(toolCallId: string, name: string, input: Record<string, unknown>, tree: unknown): unknown {
+function quizPart(toolCallId: string, input: Record<string, unknown>, output: Record<string, unknown>): NativeCallDesc {
-	return {
+	return { name: "quiz", toolCallId, input, output };
-		type: `tool-${name}`,
+}
-		toolCallId,
+
-		state: "output-available",
+function planPart(toolCallId: string, name: string, input: Record<string, unknown>, tree: unknown): NativeCallDesc {
-		input,
+	return { name, toolCallId, input, output: { ok: true, tree } };
-		output: { ok: true, tree },
-	};
 }
 
 /** A session-shaped fixture chat: probe → teaching text → check. Tree-blind
@@ -145,23 +188,28 @@ function fixtureChat() {
 	createdChats.push(chat.id);
 	chatStore.saveMessages(chat.id, [
 		user("u1", "teach me the chain rule"),
-		assistant("a1", [
+		...assistant("a1", [
 			quizPart("probe-1", { question: "What is a derivative, roughly?" }, {
 				questionId: "probe-1", kind: "quiz", questionText: "What is a derivative, roughly?",
 				correct: false, dontKnow: false, answeredAt: "2026-08-22T01:00:00.000Z",
 			}),
 		]),
-		assistant("a2", [
+		// Distinct TURNS: the native grouping canon merges consecutive
+		// assistant messages into one view group, so the fixture separates
+		// its turns with learner messages (the real record's shape).
+		user("u2", "go on"),
+		...assistant("a2", [
 			{ type: "text", text: "The derivative measures how fast a function changes." },
 			planPart("p1", "plan_init", { nodes: [], edges: [] }, { nodes: [], edges: [], currentNodeId: null, doneNodeIds: [], version: 1 }),
 		]),
-		assistant("a3", [
+		user("u3", "check me"),
+		...assistant("a3", [
 			quizPart("check-1", { question: "Check" }, {
 				questionId: "check-1", kind: "quiz", questionText: "Check", correct: true, dontKnow: false,
 				answeredAt: "2026-08-22T02:00:00.000Z",
 			}),
 		]),
-	]);
+	].flat());
 	return { chatId: chat.id, record: chatStore.getChat(chat.id)! };
 }
 
@@ -282,17 +330,16 @@ describe("transcriptView (pure)", () => {
 		createdChats.push(chat.id);
 		chatStore.saveMessages(chat.id, [
 			user("u1", "go"),
-			assistant("a1", [
+			...assistant("a1", [
 				{
-					type: "tool-research",
+					name: "research",
 					toolCallId: "r1",
-					state: "output-available",
 					input: { question: "q" },
 					output: { brief: "long brief", sources: [] },
 				},
 				{ type: "text", text: "   " },
 			]),
-		]);
+		].flat());
 		const view = transcriptView(chatStore.getChat(chat.id)!);
 		assert.match(view, /\(research tool result delivered\)/);
 		assert.doesNotMatch(view, /long brief/);
@@ -352,7 +399,7 @@ describe("the extraction pipeline (extractor → auditor → merger)", () => {
 		// a new event (vision-extraction-coverage.md).
 		const events = ledgers.readEvents();
 		const record = chatStore.getChat(chatId)!;
-		const expectedTag = batchTag(coverageSlots(record.messages as UIMessage[]));
+		const expectedTag = batchTag(coverageSlots(projectNative(record.messages)));
 		assert.deepEqual(
 			events.map((e) => [e.kind, e.ref, e.nodeId]),
 			[
@@ -368,12 +415,12 @@ describe("the extraction pipeline (extractor → auditor → merger)", () => {
 		// one entry per transcript message, fingerprinted content each —
 		// the same turns are never extracted twice.
 		const covered = ledgers.readCoverage();
-		assert.equal(covered.length, record.messages.length);
+		assert.equal(covered.length, projectNative(record.messages).length);
 		assert.ok(covered.every((c) => c.chatId === chatId && c.fp.length === 64 && c.tokens > 0));
 		assert.equal(ledgers.readCheckpoints().length, 0, "the chat path writes coverage, not the legacy checkpoint");
 
 		assert.equal(
-			coverageOf(record.messages as UIMessage[], covered, chatId).uncoveredCount,
+			coverageOf(projectNative(record.messages), covered, chatId).uncoveredCount,
 			0,
 			"every message is now covered",
 		);
@@ -973,9 +1020,9 @@ describe("the chunked pipeline (extraction coverage)", () => {
 
 		// Per-batch coverage: every message checkpointed, nothing legacy.
 		const coverage = ledgers.readCoverage();
-		assert.equal(coverage.length, record.messages.length);
+		assert.equal(coverage.length, projectNative(record.messages).length);
 		assert.equal(ledgers.readCheckpoints().length, 0);
-		assert.equal(coverageOf(record.messages as UIMessage[], coverage, chatId).uncoveredCount, 0);
+		assert.equal(coverageOf(projectNative(record.messages), coverage, chatId).uncoveredCount, 0);
 
 		// A second run is a NO-OP: nothing uncovered → no model calls, no
 		// new usage entry (no money spent on covered ground).
@@ -1028,7 +1075,7 @@ describe("the chunked pipeline (extraction coverage)", () => {
 		// Batch 1's emissions are kept and its messages stay covered.
 		assert.deepEqual(stats, { nodes: 1, edges: 0, events: 1 });
 		assert.equal(ledgers.readCoverage().length, 3, "batch 1 checkpointed its three messages");
-		const cov = coverageOf(record.messages as UIMessage[], ledgers.readCoverage(), chatId);
+		const cov = coverageOf(projectNative(record.messages), ledgers.readCoverage(), chatId);
 		assert.equal(cov.uncoveredCount, 2, "the in-flight batch's messages stay uncovered");
 
 		// The re-run — the manual extract button — picks up ONLY the
@@ -1062,25 +1109,30 @@ describe("the chunked pipeline (extraction coverage)", () => {
 			auditor: fauxEngine([passThroughAuditStep()]),
 		});
 		await pipeline.runExtraction(chatId);
-		const messages = () => chatStore.getChat(chatId)!.messages as UIMessage[];
+		// Wave B: the record is native — coverage reads the projection.
+		const record = () => chatStore.getChat(chatId)!.messages;
+		const messages = () => projectNative(record());
 		assert.equal(coverageOf(messages(), ledgers.readCoverage(), chatId).uncoveredCount, 0);
 
-		// Data parts are invisible to the extraction view — plan-block
+		// Data parts are invisible to the extraction view — a plan-block
-		// attach does NOT re-open a covered message.
+		// marker append (whose data part splices into the projected view)
-		const withDataPart = messages().map((m) =>
+		// does NOT re-open a covered message.
-			m.id === "u2"
+		chatStore.saveMessages(chatId, [
-				? { ...m, parts: [...m.parts, { type: "data-plan-blocks", planBlocks: [] } as unknown as UIMessage["parts"][number]] }
+			...record(),
-				: m,
+			newPlanBlockMessage("call_s2", { kind: "full", at: "2026-09-26T00:00:00.000Z", current: null, nodes: [], edges: [] }),
-		);
+		]);
-		chatStore.saveMessages(chatId, withDataPart);
 		const afterAttach = coverageOf(messages(), ledgers.readCoverage(), chatId);
 		assert.equal(afterAttach.uncoveredCount, 0, "data parts don't change the fingerprint");
 
 		// A quiz answer merging into an ASKING message changes its view →
 		// exactly that message re-opens, and the next run extracts it alone.
-		const mutated = messages().map((m) =>
+		// (Native: the answer arrives as the call's tool result — the
-			m.id === "s1" ? { ...m, parts: [...m.parts, { type: "text", text: "the answer merged in late" }] } : m,
+		// projected group gains the answer line.)
-		) as unknown as UIMessage[];
+		const mutated = record().map((m) =>
+			(m as { id?: string }).id === "s1"
+				? ({ ...m, content: [...(m as { content: unknown[] }).content, { type: "text", text: "the answer merged in late" }] } as never)
+				: m,
+		);
 		chatStore.saveMessages(chatId, mutated);
 		const afterMerge = coverageOf(messages(), ledgers.readCoverage(), chatId);
 		assert.equal(afterMerge.uncoveredCount, 1, "only the mutated message re-opens");

tests/graph.test.ts

@@ -17,9 +17,10 @@
 import assert from "node:assert/strict";
 import * as fs from "node:fs";
 import { after, describe, it } from "node:test";
-import type { UIMessage } from "ai";
 import type { AuditResult } from "../src/core/contracts.ts";
 import type { QuestionAnswerData } from "../src/core/question-core.ts";
+import type { LhMessage } from "../src/core/native-messages.ts";
+import { projectNative } from "../src/core/projection.ts";
 import { getGraph, graphSnapshot, mergeFindings, type GraphDeps } from "../src/core/graph.ts";
 import { coverageSlots } from "../src/core/coverage.ts";
 import { graphStore } from "../src/store/graph.ts";
@@ -32,9 +33,12 @@ const graphDeps = { chatStore, graphStore } as const satisfies GraphDeps;
 /** The session merge source for a chat — what the pipeline passes: the live
  *  transcript + its updatedAt checkpoint stamp. (Notes imports pass
  *  messages: null — see the notes-merger test below.) */
-function sessionSource(chatId: string): { messages: UIMessage[]; foldedAt: string } {
+function sessionSource(chatId: string): { messages: ReturnType<typeof projectNative>; foldedAt: string } {
+	// Wave B: the record is native history — the merger's transcript view
+	// reads through the one-way projection (same shape the extraction
+	// pipeline passes: its batch slots are projected messages).
 	const record = chatStore.getChat(chatId)!;
-	return { messages: record.messages as UIMessage[], foldedAt: record.updatedAt };
+	return { messages: projectNative(record.messages), foldedAt: record.updatedAt };
 }
 
 // ─── ledger isolation (backup-and-clear of data/graph/*.jsonl) ──────────────
@@ -72,20 +76,65 @@ after(() => {
 
 // ─── fixture builders ────────────────────────────────────────────────────────
 
-function assistant(id: string, parts: unknown[]): UIMessage {
+// Native fixture builders (Wave B): the record holds pi-native history —
-	return { id, role: "assistant", parts } as unknown as UIMessage;
+// an assistant message carrying tool calls + one tool result per call. The
+// projection reproduces the old part shapes (state output-available, input
+// = arguments, output = result details).
+interface NativeCall {
+	name: string;
+	toolCallId: string;
+	input: Record<string, unknown>;
+	output: QuestionAnswerData;
 }
 
-function user(id: string, text: string): UIMessage {
+function user(id: string, text: string): LhMessage[] {
-	return { id, role: "user", parts: [{ type: "text", text }] } as unknown as UIMessage;
+	return [{ id, role: "user", content: text, timestamp: Date.now() } as never];
+}
+
+function assistant(id: string, calls: NativeCall[]): LhMessage[] {
+	const content = calls.map((c) => ({ type: "toolCall", id: c.toolCallId, name: c.name, arguments: c.input as never }));
+	const out: LhMessage[] = [
+		{
+			id,
+			role: "assistant",
+			content,
+			api: "openai-completions",
+			provider: "openrouter",
+			model: "test",
+			usage: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+			stopReason: "stop",
+			timestamp: Date.now(),
+		} as never,
+	];
+	for (const c of calls) {
+		out.push({
+			id: `r_${c.toolCallId}`,
+			role: "toolResult",
+			toolCallId: c.toolCallId,
+			toolName: c.name,
+			content: [{ type: "text", text: "ok" }],
+			details: c.output,
+			isError: false,
+			timestamp: Date.now(),
+		} as never);
+	}
+	return out;
 }
 
 function quizPart(
 	toolCallId: string,
 	input: Record<string, unknown>,
 	output: QuestionAnswerData,
-): unknown {
+): NativeCall {
-	return { type: "tool-quiz", toolCallId, state: "output-available", input, output };
+	return { name: "quiz", toolCallId, input, output };
+}
+
+function askPart(
+	toolCallId: string,
+	input: Record<string, unknown>,
+	output: QuestionAnswerData,
+): NativeCall {
+	return { name: "ask_user_question", toolCallId, input, output };
 }
 
 function answer(over: Partial<QuestionAnswerData>): QuestionAnswerData {
@@ -102,7 +151,7 @@ function answer(over: Partial<QuestionAnswerData>): QuestionAnswerData {
 
 /** Create a chat in the real store with messages; returns the record.
  *  Tree-blind world: the plan tree is irrelevant to the merger — no tree. */
-function fixtureChat(title: string, messages: UIMessage[]) {
+function fixtureChat(title: string, messages: LhMessage[]) {
 	const chat = chatStore.createChat(title);
 	createdChats.push(chat.id);
 	chatStore.saveMessages(chat.id, messages);
@@ -110,7 +159,7 @@ function fixtureChat(title: string, messages: UIMessage[]) {
 }
 
 /** The full fixture transcript: five graded quizzes + a dismissed one + an ask. */
-function fixtureMessages(): UIMessage[] {
+function fixtureMessages(): LhMessage[] {
 	return [
 		user("u1", "teach me the fixture topic"),
 		assistant("a1", [
@@ -157,15 +206,13 @@ function fixtureMessages(): UIMessage[] {
 				{ question: "Q6", options: [{ label: "a" }, { label: "b" }], correctAnswer: "a", explanation: "e" },
 				answer({ questionId: "call-6", questionText: "Q6 text", dismissed: true }),
 			),
-			{
+			askPart(
-				type: "tool-ask_user_question",
+				"call-7",
-				toolCallId: "call-7",
+				{ question: "free text?" },
-				state: "output-available",
+				answer({ questionId: "call-7", kind: "ask", questionText: "free text?", text: "because" }),
-				input: { question: "free text?" },
+			),
-				output: answer({ questionId: "call-7", kind: "ask", questionText: "free text?", text: "because" }),
-			},
 		]),
-	];
+	].flat();
 }
 
 /** The auditor's verdict for the fixture chat: three verified propositions
@@ -332,7 +379,7 @@ describe("the merger (mergeFindings)", () => {
 					answer({ questionId: "call-9", questionText: "Q9 text", correct: true, answeredAt: "2026-08-22T03:00:00.000Z" }),
 				),
 			]),
-		]);
+		].flat());
 		chat2Id = chat2.id;
 
 		// The auditor's identity verdict: this proposition IS the alpha node.
@@ -473,7 +520,7 @@ describe("the merger (mergeFindings)", () => {
 	});
 
 	it("never string-matches without a verdict — an identical statement without linkTo is a NEW node", () => {
-		const chat3 = fixtureChat("Graph fixture 3", [user("u1", "third")]);
+		const chat3 = fixtureChat("Graph fixture 3", [user("u1", "third")].flat());
 		chat3Id = chat3.id;
 		const stats = mergeFindings(
 			chat3.id,
@@ -623,7 +670,7 @@ describe("session deletion (deleteChatTraces + deleteChatSession, wave 6)", () =
 					answer({ questionId: "d-call-1", questionText: "DQ1 text", correct: true, answeredAt: "2026-09-23T00:00:00.000Z" }),
 				),
 			]),
-		]);
+		].flat());
 		const auditA: AuditResult = {
 			propositions: [
 				{ id: "p1", name: "Shared core", statement: "Shared core statement", aliases: ["shared feel"], messages: ["du1"], evidence: ["e"], understanding: "solid" },
@@ -651,7 +698,7 @@ describe("session deletion (deleteChatTraces + deleteChatSession, wave 6)", () =
 					answer({ questionId: "e-call-1", questionText: "EQ1 text", correct: false, answeredAt: "2026-09-23T00:01:00.000Z" }),
 				),
 			]),
-		]);
+		].flat());
 		const auditB: AuditResult = {
 			propositions: [
 				{ id: "q1", name: "Shared again", statement: "Shared core, rephrased", aliases: ["B phrasing"], messages: ["eu1"], evidence: ["e"], linkTo: xId, understanding: "shaky" },
@@ -976,7 +1023,7 @@ describe("session coverage read (extraction-UX redesign, 2026-09-24)", () => {
 			user("cov_u1", "tell me about coverage reads"),
 			user("cov_u2", "and about per-session blocks"),
 			user("cov_u3", "a third distinct message"),
-		]);
+		].flat());
 		const empty = sessionCoverage(chat.id)!;
 		assert.ok(empty);
 		assert.equal(empty.totalMessages, 3);
@@ -989,7 +1036,7 @@ describe("session coverage read (extraction-UX redesign, 2026-09-24)", () => {
 
 		// Fold the first two messages: the read derives the split + the
 		// newest fold timestamp from the ledger rows.
-		const slots = coverageSlots(chatStore.getChat(chat.id)!.messages as UIMessage[]);
+		const slots = coverageSlots(projectNative(chatStore.getChat(chat.id)!.messages));
 		graphStore.appendCoverage({ chatId: chat.id, fp: slots[0]!.fp, tokens: slots[0]!.tokens, foldedAt: "2026-09-24T10:00:00.000Z" });
 		graphStore.appendCoverage({ chatId: chat.id, fp: slots[1]!.fp, tokens: slots[1]!.tokens, foldedAt: "2026-09-24T11:30:00.000Z" });
 		// Another session's row must not leak into this read.
@@ -1005,7 +1052,7 @@ describe("session coverage read (extraction-UX redesign, 2026-09-24)", () => {
 	});
 
 	it("running: true only for THIS session's chat-kind run (the registry pin)", () => {
-		const chat = fixtureChat("coverage running", [user("cov_r1", "running pin")]);
+		const chat = fixtureChat("coverage running", [user("cov_r1", "running pin")].flat());
 		const g = globalThis as { __lhExtractionRuns?: unknown };
 		const realRuns = g.__lhExtractionRuns;
 		try {

tests/jobs.test.ts

@@ -27,7 +27,6 @@ import assert from "node:assert/strict";
 import * as fs from "node:fs";
 import * as path from "node:path";
 import { after, describe, it } from "node:test";
-import type { UIMessage } from "ai";
 import { createFauxCore, fauxAssistantMessage, fauxText, fauxToolCall, type AssistantMessage, type FauxResponseStep } from "@earendil-works/pi-ai";
 import {
 	accumulateJobUsage,
@@ -41,20 +40,17 @@ import {
 	type ResearchResult,
 	type SubagentArtifactData,
 	type SteerMessage,
-	type SubagentSteerMessage,
 	type VisualResult,
 	buildProbeHandoffSteer,
-	type ProbeHandoffSteerMessage,
 } from "../src/core/contracts.ts";
-import { composeInstructions, createTeacherAgent, type TeachingAgent } from "../src/agent/teacher-agent.ts";
+import { composeInstructions, createTeacherAgent } from "../src/agent/teacher-agent.ts";
 import { createTeacherTools } from "../src/agent/tools.ts";
 import { webTools } from "../src/agent/tools/web.ts";
 import { handleChatRequest } from "../src/server/chat-handler.ts";
-import { recordToPiMessages } from "../src/server/pi/record-adapter.ts";
 import { abortJob, claimSteers, deliverJobResult, recoverStaleJobs, setJobRespawn, setTurnRunner } from "../src/server/jobs.ts";
 import { registerJobAbort, unregisterJobAbort } from "../src/agent/subagents/aborts.ts";
 import { beginTurn, endTurn } from "../src/server/turn-liveness.ts";
-import { persistTurn, withMessageIds } from "../src/server/turn-service.ts";
+import { persistTurn } from "../src/server/turn-service.ts";
 import { chatStore } from "../src/store/chats.ts";
 import { jobStore } from "../src/store/jobs.ts";
 import { createJobRunner, pdfModelOverride, researchModelOverride } from "../src/agent/subagents/runner.ts";
@@ -62,6 +58,9 @@ import { providerKeyMissing, type ModelSlotName } from "../src/core/settings.ts"
 import type { PiEngine } from "../src/agent/models.ts";
 import type { SearchProvider } from "../src/core/search.ts";
 import { PATHS } from "../config.ts";
+import { projectNative } from "../src/core/projection.ts";
+import type { LhMessage } from "../src/core/native-messages.ts";
+import type { SteerInput, TurnInput } from "../src/core/input-events.ts";
 
 const JOBS_DIR = path.join(PATHS.data, "jobs");
 
@@ -77,6 +76,36 @@ function trackChat(id: string) {
 	createdChats.push(id);
 }
 
+/** Wave B native fixture: user text + an assistant tool call + its ack —
+ *  the record is agent history; the runner's transcript scan (input
+ *  resolution) reads it through the projection. */
+function nativeToolMessages(text: string, tool: string, toolCallId: string, input: unknown): LhMessage[] {
+	return [
+		{ id: "u1", role: "user", content: text, timestamp: 1 } as never,
+		{
+			id: "a1",
+			role: "assistant",
+			content: [{ type: "toolCall", id: toolCallId, name: tool, arguments: input as never }],
+			api: "openai-completions",
+			provider: "openrouter",
+			model: "test",
+			usage: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+			stopReason: "toolUse",
+			timestamp: 1,
+		} as never,
+		{
+			id: "r1",
+			role: "toolResult",
+			toolCallId,
+			toolName: tool,
+			content: [{ type: "text", text: "Dispatched." }],
+			details: "Dispatched.",
+			isError: false,
+			timestamp: 1,
+		} as never,
+	];
+}
+
 function trackJob(id: string) {
 	createdJobs.push(id);
 }
@@ -132,11 +161,13 @@ async function drain(res: Response): Promise<string> {
 	return res.text();
 }
 
-function post(chatId: string, messages: unknown[]): Request {
+function post(chatId: string, input: unknown): Request {
 	return new Request("http://test/api/chat", {
 		method: "POST",
 		headers: { "Content-Type": "application/json" },
-		body: JSON.stringify({ chatId, messages }),
+		// Wave B: the input-events contract — one explicit event, never a
+		// client transcript.
+		body: JSON.stringify({ chatId, input }),
 	});
 }
 
@@ -192,19 +223,21 @@ describe("steer helpers (contracts.ts)", () => {
 	const demo: DemoResult = { title: "T", html: "<html></html>", tested: true, notes: "ok" };
 	const visual: VisualResult = { svg: "<svg/>", notes: "ok" };
 
-	it("buildSubagentSteer: user-role, metadata-marked, artifact on the data part, brief on the text part", () => {
+	it("buildSubagentSteer: a native marker — brief on the model-facing content, artifact payload in details", () => {
 		const job = { id: "job_x", kind: "research" as const, toolCallId: "call-x" };
 		const steer = buildSubagentSteer(job, research);
 		assert.equal(steer.id, "steer_job_x", "deterministic id per job — idempotent delivery");
-		assert.equal(steer.role, "user");
+		// Wave B: steers are LhMarkerMessage customs — role "custom", the
-		assert.deepEqual(steer.metadata, { subagentResult: { jobId: "job_x", kind: "research", toolCallId: "call-x" } });
+		// model reads `content`, the UI reads `details` (never model-visible).
-		const [text, data] = steer.parts;
+		assert.equal(steer.role, "custom");
-		assert.equal(text.type, "text");
+		assert.equal(steer.customType, "subagent-steer");
-		assert.ok(text.type === "text" && text.text.includes("BRIEF"), "the model-facing text carries the brief");
+		assert.equal(steer.display, true);
-		assert.equal(data.type, "data-subagent-artifact");
+		assert.ok(steer.content.includes("BRIEF"), "the model-facing text carries the brief");
-		assert.ok(data.type === "data-subagent-artifact");
+		const data = steer.details as { jobId: string; kind: string; toolCallId: string; result: ResearchResult };
-		assert.equal(data.data.kind, "research");
+		assert.equal(data.jobId, "job_x");
-		assert.deepEqual(data.data.result, research);
+		assert.equal(data.kind, "research");
+		assert.equal(data.toolCallId, "call-x");
+		assert.deepEqual(data.result, research);
 	});
 
 	it("accumulateJobUsage: sums per model call; fields NO call reported stay undefined (absent is not zero)", () => {
@@ -248,19 +281,15 @@ describe("steer helpers (contracts.ts)", () => {
 		}, "lastStep always mirrors the LATEST call, never the sums");
 	});
 
-	it("buildAbortSteer: teacher-facing text + the data-subagent-aborted marker part (the message type), same deterministic id space as the result steer", () => {
+	it("buildAbortSteer: a subagent-abort marker — teacher-facing text on content, the abort payload in details", () => {
 		const steer = buildAbortSteer({ id: "job_c", kind: "demo", toolCallId: "call-c" });
 		assert.equal(steer.id, "steer_job_c", "same id space — steerDelivered treats either as delivered");
-		assert.equal(steer.role, "user");
+		assert.equal(steer.role, "custom");
-		assert.equal(steer.metadata.subagentResult.aborted, true);
+		assert.equal(steer.customType, "subagent-abort");
-		assert.equal(steer.metadata.subagentResult.jobId, "job_c");
+		assert.ok(/aborted/.test(steer.content), "the teacher-facing text names the abort");
-		assert.equal(steer.parts.length, 2);
+		// The marker's customType is the message type: the UI renders the
-		assert.ok(steer.parts[0]!.type === "text" && /aborted/.test(steer.parts[0].text));
+		// abort badge off the projection (demos.test.tsx pins the card).
-		// The marker PART is the message type (the custom-message scheme): the
+		assert.deepEqual(steer.details, { jobId: "job_c", kind: "demo", toolCallId: "call-c", aborted: true });
-		// UI renders the abort badge off it — metadata stays for pump mechanics.
-		const marker = steer.parts[1]!;
-		assert.equal(marker.type, "data-subagent-aborted");
-		assert.deepEqual(marker.data, { jobId: "job_c", kind: "demo", toolCallId: "call-c", aborted: true });
 	});
 
 	it("isSubagentFailure: failure shapes only (empty html/svg, failure brief)", () => {
@@ -292,28 +321,26 @@ describe("steer helpers (contracts.ts)", () => {
 		const failDemo = buildSubagentSteer({ id: "j2", kind: "demo", toolCallId: "c" }, { title: "T", html: "", tested: true, notes: "FAILED: boom" });
 		const failVisual = buildSubagentSteer({ id: "j3", kind: "visual", toolCallId: "c" }, { svg: "", notes: "FAILED: boom" });
 		for (const steer of [failResearch, failDemo, failVisual]) {
-			const text = steer.parts[0];
+			assert.ok(!steer.content.includes("rendered in the lesson"), "failure text never claims the artifact landed");
-			assert.ok(text.type === "text" && !text.text.includes("rendered in the lesson"), "failure text never claims the artifact landed");
 		}
-		assert.ok(failResearch.parts[0].type === "text" && failResearch.parts[0].text.includes("flag the uncertainty"));
+		assert.ok(failResearch.content.includes("flag the uncertainty"));
 	});
 
 	it("pdf steers (sources v0): brief + page citations on success, PDF failed: shape on failure, abort wording per kind", () => {
 		const pdf: PdfResult = { path: "/tmp/doc.pdf", question: "q?", brief: "The formula is on p. 2.", pagesRead: [2], pagesConsulted: [1, 2] };
 		const ok = buildSubagentSteer({ id: "jp", kind: "pdf", toolCallId: "cp" }, pdf);
-		assert.ok(ok.parts[0].type === "text" && ok.parts[0].text.includes("page citations"), "the teacher is told to cite pages");
+		assert.ok(ok.content.includes("page citations"), "the teacher is told to cite pages");
-		assert.ok(ok.parts[0].type === "text" && ok.parts[0].text.includes("The formula is on p. 2."));
+		assert.ok(ok.content.includes("The formula is on p. 2."));
-		assert.equal(ok.parts[1].type, "data-subagent-artifact");
+		assert.equal((ok.details as { kind: string }).kind, "pdf");
-		assert.equal((ok.parts[1] as { data: SubagentArtifactData }).data.kind, "pdf");
+		assert.deepEqual((ok.details as { result: unknown }).result, pdf);
-		assert.deepEqual((ok.parts[1] as { data: SubagentArtifactData }).data.result, pdf);
 		// failure shape mirrors research
 		assert.equal(isSubagentFailure("pdf", pdf), false);
 		assert.equal(isSubagentFailure("pdf", { ...pdf, brief: "PDF failed: unreadable" }), true);
 		const fail = buildSubagentSteer({ id: "jf", kind: "pdf", toolCallId: "cf" }, { ...pdf, brief: "PDF failed: unreadable" });
-		assert.ok(fail.parts[0].type === "text" && fail.parts[0].text.includes("flag the gap"));
+		assert.ok(fail.content.includes("flag the gap"));
 		// abort wording names the PDF job
 		const aborted = buildAbortSteer({ id: "ja", kind: "pdf", toolCallId: "ca" });
-		assert.ok(aborted.parts[0].type === "text" && aborted.parts[0].text.includes("PDF reading job"));
+		assert.ok(aborted.content.includes("PDF reading job"));
 	});
 });
 
@@ -325,12 +352,12 @@ describe("steer helpers (contracts.ts)", () => {
  * exactly as it will in production after the wake turn completes.
  */
 function fakeDeliver() {
-	const steers: SubagentSteerMessage[] = [];
+	const steers: SteerMessage[] = [];
 	return {
 		steers,
-		deliver: async (steer: SubagentSteerMessage) => {
+		deliver: async (steer: SteerMessage) => {
 			steers.push(steer);
-			const jobId = steer.metadata.subagentResult.jobId;
+			const jobId = (steer.details as { jobId: string }).jobId;
 			const job = jobStore.getJob(jobId);
 			if (job && job.status === "running") {
 				const failed = job.result ? isSubagentFailure(job.kind, job.result as never) : true;
@@ -376,18 +403,21 @@ describe("dispatch (async protocol §2)", () => {
 			jobStore,
 			spawn: (job, input) => void testRunner.runJob(job.id, input),
 		});
-		const agent = (outgoing: UIMessage[]): TeachingAgent =>
+		// The handler hands the factory the native build options — the
-			createTeacherAgent(undefined, { engine, tools, messages: recordToPiMessages(outgoing) });
+		// record IS the agent state (Wave B: no adapter conversion).
+		const agent: Parameters<typeof handleChatRequest>[1] = (opts) =>
+			createTeacherAgent(undefined, { engine, tools, messages: opts.messages });
 
 		researchModelOverride.current = researcherModel();
-		const firstUser = { id: "u1", role: "user", parts: [{ type: "text", text: "teach me graph rendering" }] };
+		const body = await drain(
-		const body = await drain(await handleChatRequest(post(chat.id, [firstUser]), agent));
+			await handleChatRequest(post(chat.id, { type: "text", text: "teach me graph rendering" }), agent),
+		);
 
 		// The teacher's SAME turn carried on past the tool call.
 		assert.ok(body.includes("Back with the brief."), "the turn continued after the dispatch");
 
-		const saved = chatStore.getChat(chat.id)!;
+		const saved = projectNative(chatStore.getChat(chat.id)!.messages);
-		const part = saved.messages[1]!.parts.find((p) => p.type === "tool-research");
+		const part = saved[1]!.parts.find((p) => p.type === "tool-research");
 		assert.ok(part && part.type === "tool-research", "research tool part persisted");
 		assert.equal(part.state, "output-available", "the part resolved at dispatch time (not held pending)");
 		assert.equal(typeof (part as { output?: unknown }).output, "string", "the output is the ack, not the result");
@@ -403,12 +433,12 @@ describe("dispatch (async protocol §2)", () => {
 		assert.equal(done.status, "done");
 		assert.equal(done.activity, "delivered");
 
-		// The steer carries the brief + artifact for the (UI) renderer.
+		// The steer carries the brief on its model-facing content; the
+		// artifact payload rides details for the (UI) renderer.
 		assert.equal(delivery.steers.length, 1, "exactly one steer — one job, one result");
 		const steer = delivery.steers[0]!;
-		assert.equal(steer.metadata.subagentResult.jobId, job!.id);
+		assert.equal((steer.details as { jobId: string }).jobId, job!.id);
-		const text = steer.parts[0];
+		assert.ok(steer.content.includes("sigma.js v3 is current"), "steer text carries the brief");
-		assert.ok(text.type === "text" && text.text.includes("sigma.js v3 is current"), "steer text carries the brief");
 
 		// Search threading (2026-09-20): the researcher's web_search ran on
 		// the INJECTED port — the stub saw the scripted query, no network.
@@ -460,17 +490,7 @@ describe("research runner (async protocol §3)", () => {
 
 		// A dispatched research part in the stored chat (the input is also
 		// what the runner falls back to on a crash-recovery re-spawn).
-		chatStore.saveMessages(chat.id, [
+		chatStore.saveMessages(chat.id, nativeToolMessages("which sigma version?", "research", "call-run1", RESEARCH_INPUT));
-			{ id: "u1", role: "user", parts: [{ type: "text", text: "which sigma version?" }] },
-			{
-				id: "a1",
-				role: "assistant",
-				parts: [
-					{ type: "text", text: "Checking." },
-					{ type: "tool-research", toolCallId: "call-run1", state: "output-available", input: RESEARCH_INPUT, output: "Dispatched." },
-				],
-			},
-		] as never);
 
 		const job = jobStore.createJob({ kind: "research", chatId: chat.id, toolCallId: "call-run1" });
 		trackJob(job.id);
@@ -503,14 +523,7 @@ describe("research runner (async protocol §3)", () => {
 	it("a failing runner still steers (the teacher learns the outcome) and the job lands error", async () => {
 		const chat = chatStore.createChat("Test: runner failure");
 		trackChat(chat.id);
-		chatStore.saveMessages(chat.id, [
+		chatStore.saveMessages(chat.id, nativeToolMessages("hi", "research", "call-err1", RESEARCH_INPUT));
-			{ id: "u1", role: "user", parts: [{ type: "text", text: "hi" }] },
-			{
-				id: "a1",
-				role: "assistant",
-				parts: [{ type: "tool-research", toolCallId: "call-err1", state: "output-available", input: RESEARCH_INPUT, output: "Dispatched." }],
-			},
-		] as never);
 
 		const job = jobStore.createJob({ kind: "research", chatId: chat.id, toolCallId: "call-err1" });
 		trackJob(job.id);
@@ -534,24 +547,14 @@ describe("research runner (async protocol §3)", () => {
 
 		const steer = delivery.steers[0]!;
 		assert.ok(steer, "failure still delivers a steer");
-		const text = steer.parts[0];
+		assert.ok(steer.content.includes("Research failed: model exploded"), "failure brief on the steer text");
-		assert.ok(text.type === "text" && text.text.includes("Research failed: model exploded"), "failure brief on the steer text");
+		assert.deepEqual(((steer.details as { result: ResearchResult }).result).sources, []);
-		const data = steer.parts[1];
-		assert.ok(data.type === "data-subagent-artifact");
-		assert.deepEqual((data.data.result as ResearchResult).sources, []);
 	});
 
 	it("runJob resolves the input from the transcript when dispatch-time input is absent (crash recovery)", async () => {
 		const chat = chatStore.createChat("Test: transcript input fallback");
 		trackChat(chat.id);
-		chatStore.saveMessages(chat.id, [
+		chatStore.saveMessages(chat.id, nativeToolMessages("go", "research", "call-fb1", RESEARCH_INPUT));
-			{ id: "u1", role: "user", parts: [{ type: "text", text: "go" }] },
-			{
-				id: "a1",
-				role: "assistant",
-				parts: [{ type: "tool-research", toolCallId: "call-fb1", state: "output-available", input: RESEARCH_INPUT, output: "Dispatched." }],
-			},
-		] as never);
 		const job = jobStore.createJob({ kind: "research", chatId: chat.id, toolCallId: "call-fb1" });
 		trackJob(job.id);
 
@@ -595,14 +598,7 @@ describe("pdf runner (sources v0)", () => {
 	it("runJob completes a pdf job: brief + pagesConsulted land on the record, citation steer delivered", async () => {
 		const chat = chatStore.createChat("Test: pdf runner");
 		trackChat(chat.id);
-		chatStore.saveMessages(chat.id, [
+		chatStore.saveMessages(chat.id, nativeToolMessages("read this pdf", "pdf", "call-pdf1", PDF_INPUT));
-			{ id: "u1", role: "user", parts: [{ type: "text", text: "read this pdf" }] },
-			{
-				id: "a1",
-				role: "assistant",
-				parts: [{ type: "tool-pdf", toolCallId: "call-pdf1", state: "output-available", input: PDF_INPUT, output: "Dispatched." }],
-			},
-		] as never);
 
 		const job = jobStore.createJob({ kind: "pdf", chatId: chat.id, toolCallId: "call-pdf1" });
 		trackJob(job.id);
@@ -627,9 +623,8 @@ describe("pdf runner (sources v0)", () => {
 
 		assert.equal(delivery.steers.length, 1, "one job, one steer");
 		const steer = delivery.steers[0]!;
-		assert.equal(steer.metadata.subagentResult.kind, "pdf");
+		assert.equal((steer.details as { kind: string }).kind, "pdf");
-		const text = steer.parts[0];
+		assert.ok(steer.content.includes("integral rule"), "steer text carries the brief");
-		assert.ok(text.type === "text" && text.text.includes("integral rule"), "steer text carries the brief");
 	});
 
 	it("an unreadable source: the job lands error with the PDF failed: brief and the steer flags the gap", async () => {
@@ -656,8 +651,7 @@ describe("pdf runner (sources v0)", () => {
 		assert.deepEqual(result.pagesConsulted, []);
 
 		const steer = delivery.steers[0]!;
-		const text = steer.parts[0];
+		assert.ok(steer.content.includes("flag the gap"), "the teacher learns to flag the gap");
-		assert.ok(text.type === "text" && text.text.includes("flag the gap"), "the teacher learns to flag the gap");
 	});
 });
 
@@ -693,10 +687,10 @@ describe("researcher agent", () => {
  */
 describe("wake pipeline (src/server/jobs.ts)", () => {
 	/** A chat with a finished job ready for delivery. */
-	function setup(kind: "research" | "demo" = "research"): { chatId: string; jobId: string; steer: SubagentSteerMessage } {
+	function setup(kind: "research" | "demo" = "research"): { chatId: string; jobId: string; steer: SteerMessage } {
 		const chat = chatStore.createChat("Test: wake pipeline");
 		trackChat(chat.id);
-		chatStore.saveMessages(chat.id, [{ id: "u1", role: "user", parts: [{ type: "text", text: "hello" }] }] as never);
+		chatStore.saveMessages(chat.id, [{ id: "u1", role: "user", content: "hello", timestamp: 1 } as never]);
 
 		const job = jobStore.createJob({ kind, chatId: chat.id, toolCallId: `call-${jobStore.listJobs(chat.id).length}` });
 		trackJob(job.id);
@@ -709,29 +703,22 @@ describe("wake pipeline (src/server/jobs.ts)", () => {
 	it("delivers a PROBE HANDOFF steer the same way — the teacher's wake turn", async () => {
 		const chat = chatStore.createChat("Test: probe handoff wake");
 		trackChat(chat.id);
-		// The concluded probe: a persisted probe_done part (the seam the
+		// The concluded probe: a persisted probe_done call + result (the
-		// chat-handler's construction branch keys on) and no open question.
+		// native seam the chat-handler's construction branch keys on) and no
-		chatStore.saveMessages(chat.id, [
+		// open question.
-			{ id: "u1", role: "user", parts: [{ type: "text", text: "teach me calc" }] },
+		chatStore.saveMessages(chat.id, nativeToolMessages("teach me calc", "probe_done", "call-pd", { ok: true }));
-			{
-				id: "a1",
-				role: "assistant",
-				parts: [
-					{ type: "tool-probe_done", state: "output-available", output: { ok: true } },
-				],
-			},
-		] as never);
 		const handoff = buildProbeHandoffSteer(chat.id);
-		let seen: { chatId: string; lastMessage: ProbeHandoffSteerMessage } | null = null;
+		let seen: { chatId: string; steer: SteerMessage } | undefined;
-		setTurnRunner(async (cid, messages) => {
+		setTurnRunner(async (cid, input) => {
-			seen = { chatId: cid, lastMessage: messages[messages.length - 1] as ProbeHandoffSteerMessage };
+			seen = { chatId: cid, steer: (input as SteerInput).steer as SteerMessage };
 			return 200;
 		});
 
 		await deliverJobResult(handoff);
-		await waitFor(() => seen !== null, 8000, "handoff wake fired");
+		await waitFor(() => seen !== undefined, 8000, "handoff wake fired");
-		assert.equal(seen!.chatId, chat.id);
+		const firedHandoff = seen!;
-		assert.equal(seen!.lastMessage.id, `steer_probe_${chat.id}`, "the handoff is the wake turn's final input message");
+		assert.equal(firedHandoff.chatId, chat.id);
+		assert.equal(firedHandoff.steer.id, `steer_probe_${chat.id}`, "the handoff IS the wake turn's input");
 	});
 
 	it("a redelivered handoff dedupes via the transcript (idempotent by steer id)", async () => {
@@ -752,9 +739,9 @@ describe("wake pipeline (src/server/jobs.ts)", () => {
 
 	it("delivers: fires the turn runner with the record + steer, then flips the job done", async () => {
 		const { chatId, jobId, steer } = setup();
-		let seen: { chatId: string; lastMessage: unknown } | null = null;
+		let seen: { chatId: string; steer: SteerMessage } | undefined;
-		setTurnRunner(async (cid, messages) => {
+		setTurnRunner(async (cid, input) => {
-			seen = { chatId: cid, lastMessage: messages[messages.length - 1] };
+			seen = { chatId: cid, steer: (input as SteerInput).steer as SteerMessage };
 			return 200;
 		});
 
@@ -764,9 +751,8 @@ describe("wake pipeline (src/server/jobs.ts)", () => {
 		assert.equal(jobStore.getJob(jobId)!.status, "done");
 		assert.equal(jobStore.getJob(jobId)!.activity, "delivered");
 		assert.ok(seen, "the turn runner fired");
-		assert.equal((seen as { chatId: string }).chatId, chatId);
+		assert.equal(seen.chatId, chatId);
-		const last = (seen as { lastMessage: SubagentSteerMessage }).lastMessage;
+		assert.equal(seen.steer.id, steer.id, "the steer IS the wake turn's input");
-		assert.equal(last.id, steer.id, "the steer is the wake turn's final input message");
 	});
 
 	it("waits while a question part is pending, and fires once it clears", async () => {
@@ -777,16 +763,22 @@ describe("wake pipeline (src/server/jobs.ts)", () => {
 			return 200;
 		});
 
-		// An unanswered quiz part blocks the wake (provider conversion would
+		// A dangling question call blocks the wake (the model would reject an
-		// break on an input-available tool call).
+		// unanswered tool call — fork 1: the record ends at the call).
 		chatStore.saveMessages(chatId, [
-			{ id: "u1", role: "user", parts: [{ type: "text", text: "hello" }] },
+			{ id: "u1", role: "user", content: "hello", timestamp: 1 } as never,
 			{
 				id: "a1",
 				role: "assistant",
-				parts: [{ type: "tool-quiz", toolCallId: "quiz-call", state: "input-available", input: { question: "q", choices: ["a", "b"] } }],
+				content: [{ type: "toolCall", id: "quiz-call", name: "quiz", arguments: { question: "q", choices: ["a", "b"] } as never }],
-			},
+				api: "openai-completions",
-		] as never);
+				provider: "openrouter",
+				model: "test",
+				usage: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+				stopReason: "toolUse",
+				timestamp: 1,
+			} as never,
+		]);
 
 		// The delivery promise floats while the quiz blocks — awaiting it now
 		// would deadlock the test (the pump defers until the gate opens).
@@ -796,17 +788,21 @@ describe("wake pipeline (src/server/jobs.ts)", () => {
 		assert.equal(fired, 0, "no wake while the quiz is pending");
 		assert.equal(jobStore.getJob(jobId)!.status, "running", "job stays running while blocked");
 
-		// The learner answers: the pending part clears (client adds output).
+		// The learner answers: the real tool result clears the dangling call.
 		const record = chatStore.getChat(chatId)!;
-		const answered = record.messages.map((m) =>
+		chatStore.saveMessages(chatId, [
-			m.id === "a1"
+			...record.messages,
-				? {
+			{
-						...m,
+				id: "r1",
-						parts: [{ type: "tool-quiz", toolCallId: "quiz-call", state: "output-available", input: { question: "q", choices: ["a", "b"] }, output: { answer: "a", correct: true, explanation: "" } }],
+				role: "toolResult",
-					}
+				toolCallId: "quiz-call",
-				: m,
+				toolName: "quiz",
-		);
+				content: [{ type: "text", text: "answered" }],
-		chatStore.saveMessages(chatId, answered as never);
+				details: { answer: "a", correct: true, explanation: "" },
+				isError: false,
+				timestamp: 1,
+			} as never,
+		]);
 
 		await waitFor(() => fired > 0, 8000, "wake after the quiz answer");
 		await delivery; // now it resolves — the steer was delivered
@@ -873,15 +869,20 @@ describe("claimSteers + pump duplicate-guard (continuation coalescing)", () => {
 		assert.equal(fired, 0, "the pump never fires a wake for a claimed steer");
 	});
 
-	it("finalizes already-delivered steers without returning them (a wake raced in)", async () => {
+	it("finalizes already-delivered steers; the handler's steerDelivered filter keeps one copy (a wake raced in)", async () => {
 		const { chatId, jobId, steer } = setup();
 		const record = chatStore.getChat(chatId)!;
 		chatStore.saveMessages(chatId, [...record.messages, steer] as never);
 
 		const delivery = deliverJobResult(steer);
-		await delay(100); // let the pump see it first (its top-of-loop idempotent skip)
+		await delay(100); // let the pump's top-of-loop idempotent skip run
 		const claimed = claimSteers(chatId);
-		assert.equal(claimed.length, 0, "delivered steers are not re-claimed");
+		// The pump itself finalizes already-delivered steers at the top of
+		// its loop — the queue is empty by the time a racing turn claims.
+		// (A steer that DID ride the queue gets claimed whole; the HANDLER's
+		// steerDelivered filter keeps exactly one copy at append.)
+		assert.equal(claimed.length, 0, "the pump finalized the delivered steer without firing a wake");
+		assert.ok(steerDelivered(chatStore.getChat(chatId)!.messages, steer.id), "the record already holds it");
 		assert.equal(jobStore.getJob(jobId)!.status, "done");
 		await delivery;
 	});
@@ -890,7 +891,7 @@ describe("claimSteers + pump duplicate-guard (continuation coalescing)", () => {
 		assert.deepEqual(claimSteers("chat_never_existed"), []);
 	});
 
-	it("pump path: a steer already carried by the incoming turn body is finalized, never appended again (duplicate-key bug, 2026-09-18)", async () => {
+	it("pump path: a steer coalesced into the record mid-flight is claimed, filtered at append, never double-fired (duplicate-key bug, 2026-09-18)", async () => {
 		const { chatId, jobId, steer } = setup();
 		// Own runner: this chat's gates are OPEN, so the pump would otherwise
 		// fire whatever runner the NEXT test registers (leaked counter).
@@ -899,29 +900,29 @@ describe("claimSteers + pump duplicate-guard (continuation coalescing)", () => {
 			fired++;
 			return 200;
 		});
-		// The wake pump's request ALREADY carries the steer (it dequeues only
+		// The racing turn's write-ahead ALREADY landed the steer in the record
-		// after the turn returns), and the record does not — the exact window
+		// while the entry is still queued — the exact window the handler
-		// the chat handler claims in.
+		// claims in (the pump dequeues only after the turn returns 200).
 		const delivery = deliverJobResult(steer);
 		await delay(300); // the pump is inside waitForIdle's grace (750ms)
-		const incoming = [...(chatStore.getChat(chatId)!.messages as never[]), steer];
+		const incoming = [...chatStore.getChat(chatId)!.messages, steer];
-		const claimed = claimSteers(chatId, incoming);
+		chatStore.saveMessages(chatId, incoming); // the racing turn's write-ahead persist
-		assert.equal(claimed.length, 0, "the already-carried steer is not re-claimed");
+		const claimed = claimSteers(chatId);
-		assert.equal(jobStore.getJob(jobId)!.status, "done", "job still finalizes — the turn delivers it");
+		assert.equal(claimed.length, 1, "the queued steer is claimed — its delivery rides the turn");
+		assert.equal(jobStore.getJob(jobId)!.status, "done", "job still finalizes — the claim resolves the delivery");
 		await delivery;
 		assert.deepEqual(claimSteers(chatId), [], "queue is drained");
-		// The handler persists the outgoing write-ahead immediately after the
+		// The handler appends only steers NOT already in the record
-		// claim — the pump's post-idle re-check reads the RECORD (not the
+		// (steerDelivered) — the write-ahead keeps exactly ONE copy of the
-		// queue), so without this the wake would double-fire at grace-end.
+		// steer id, and the pump's post-idle re-check reads the RECORD and
-		const record2 = chatStore.getChat(chatId)!;
+		// skips the delivered id.
-		chatStore.saveMessages(chatId, [...record2.messages, ...incoming] as never);
+		const appends = claimed.filter((c) => !steerDelivered(chatStore.getChat(chatId)!.messages, c.id));
-		await delay(800); // the pump's grace elapses — the delivered steer is skipped
+		assert.equal(appends.length, 0, "the already-persisted steer never appends again");
-		assert.equal(fired, 0, "the claimed-and-carried steer never double-fires a wake");
+		const outgoing = [...chatStore.getChat(chatId)!.messages, ...appends];
-		// The handler's outgoing = incoming + claimed: with claimed empty the
+		const ids = outgoing.map((m) => m.id);
-		// write-ahead holds exactly ONE copy of the steer id.
-		const outgoing = [...incoming, ...claimed] as never[];
-		const ids = outgoing.map((m: { id: string }) => m.id);
 		assert.equal(ids.filter((id) => id === steer.id).length, 1, "exactly one steer copy persists");
+		await delay(800); // the pump's grace elapses — its re-check sees the delivered id
+		assert.equal(fired, 0, "the claimed-and-persisted steer never double-fires a wake");
 	});
 
 	it("pump duplicate-guard: a steer coalesced into the record while the gates were closed is never double-fired", async () => {
@@ -932,15 +933,21 @@ describe("claimSteers + pump duplicate-guard (continuation coalescing)", () => {
 			return 200;
 		});
 
-		// Gates closed: a pending quiz parks the pump in waitForIdle.
+		// Gates closed: a dangling question call parks the pump in waitForIdle.
 		chatStore.saveMessages(chatId, [
-			{ id: "u1", role: "user", parts: [{ type: "text", text: "hello" }] },
+			{ id: "u1", role: "user", content: "hello", timestamp: 1 } as never,
 			{
 				id: "a1",
 				role: "assistant",
-				parts: [{ type: "tool-quiz", toolCallId: "quiz-call", state: "input-available", input: { question: "q", choices: ["a", "b"] } }],
+				content: [{ type: "toolCall", id: "quiz-call", name: "quiz", arguments: { question: "q", choices: ["a", "b"] } as never }],
-			},
+				api: "openai-completions",
-		] as never);
+				provider: "openrouter",
+				model: "test",
+				usage: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+				stopReason: "toolUse",
+				timestamp: 1,
+			} as never,
+		]);
 		const delivery = deliverJobResult(steer);
 		await delay(1200);
 		assert.equal(fired, 0, "parked behind the pending quiz");
@@ -953,15 +960,20 @@ describe("claimSteers + pump duplicate-guard (continuation coalescing)", () => {
 
 		// The learner answers: the gates open — the parked pump must see the
 		// delivered steer via its post-idle re-check, NOT fire a second turn.
-		const answered = chatStore.getChat(chatId)!.messages.map((m) =>
+		const answeredRecord = chatStore.getChat(chatId)!;
-			m.id === "a1"
+		chatStore.saveMessages(chatId, [
-				? {
+			...answeredRecord.messages,
-						...m,
+			{
-						parts: [{ type: "tool-quiz", toolCallId: "quiz-call", state: "output-available", input: { question: "q", choices: ["a", "b"] }, output: { answer: "a", correct: true, explanation: "" } }],
+				id: "r1",
-					}
+				role: "toolResult",
-				: m,
+				toolCallId: "quiz-call",
-		);
+				toolName: "quiz",
-		chatStore.saveMessages(chatId, answered as never);
+				content: [{ type: "text", text: "answered" }],
+				details: { answer: "a", correct: true, explanation: "" },
+				isError: false,
+				timestamp: 1,
+			} as never,
+		]);
 
 		await delivery;
 		await delay(1500);
@@ -990,57 +1002,104 @@ function delay(ms: number): Promise<void> {
 
 // ─── persist id hygiene (the duplicate-empty-key bug) ────────────────────────
 
-describe("persistTurn id hygiene", () => {
+describe("persistTurn (native history, Wave B)", () => {
-	it("withMessageIds fills EMPTY ids (server-only synthesized messages) and preserves existing ones", () => {
+	it("stamps EMPTY ids (pi minted no id) at the canonical write and preserves existing ones", () => {
-		const filled = withMessageIds([
+		const chat = chatStore.createChat("Test: persist stamps ids");
-			{ id: "", role: "assistant", parts: [{ type: "text", text: "wake turn" }] },
-			{ id: "client-id", role: "user", parts: [{ type: "text", text: "hi" }] },
-		]);
-		assert.notEqual(filled[0]!.id, "", "empty id replaced");
-		assert.match(filled[0]!.id, /^msg_/);
-		assert.equal(filled[1]!.id, "client-id", "client-authored id untouched");
-		assert.notEqual(filled[0]!.id, filled[1]!.id);
-	});
-
-	it("persistTurn dedupes same-id continuation copies, keeping the LAST (the SDK's merged superset)", () => {
-		// The coalescing shape: a steer (user-role) rides a quiz-answer
-		// continuation AFTER the assistant message being continued, so the
-		// SDK's onFinish list carries the input copy AND the extended
-		// response copy under one id — the record must keep only the merge.
-		const chat = chatStore.createChat("Test: dedupe continuation copies");
 		trackChat(chat.id);
-		const short: UIMessage = { id: "msg_dup_1", role: "assistant", parts: [{ type: "text", text: "step 1" }] };
+		const stamped = persistTurn(chatStore, chat.id, 0, [
-		const long: UIMessage = { id: "msg_dup_1", role: "assistant", parts: [{ type: "text", text: "step 1" }, { type: "text", text: "step 2 (continued)" }] };
+			{ id: "", role: "user", content: "wake turn", timestamp: 1 } as never,
-		persistTurn(chatStore, chat.id, [
+			{
-			{ id: "u1", role: "user", parts: [{ type: "text", text: "hi" }] },
+				id: "msg_kept",
-			short,
+				role: "assistant",
-			{ id: "steer_x", role: "user", parts: [{ type: "text", text: "research complete" }] },
+				content: [{ type: "text", text: "hi" }],
-			long,
+				api: "openai-completions",
+				provider: "openrouter",
+				model: "test",
+				usage: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+				stopReason: "stop",
+				timestamp: 1,
+			} as never,
 		], false);
+		assert.notEqual(stamped[0]!.id, "", "empty id replaced");
+		assert.match(stamped[0]!.id, /^msg_/);
+		assert.equal(stamped[1]!.id, "msg_kept", "server-authored id untouched");
 		const record = chatStore.getChat(chat.id)!;
-		assert.equal(record.messages.length, 3, "the duplicate entry is dropped");
+		assert.equal(record.messages.length, 2, "both messages persisted");
-		assert.deepEqual(
+		assert.ok(record.messages.every((m) => m.id && m.id.length > 0), "no empty ids survive persist");
-			record.messages.map((m) => m.id),
-			["u1", "steer_x", "msg_dup_1"],
-			"order preserved, steer before the merged assistant copy",
-		);
-		const merged = record.messages[2]!;
-		assert.equal(merged.parts.length, 2, "the KEPT copy is the extended one");
-		assert.equal((merged.parts[1] as { text: string }).text, "step 2 (continued)");
 	});
 
-	it("persistTurn saves every message with a unique non-empty id (wake turns never re-POSTed)", () => {
+	it("baseCount slices the turn's own messages (the agent's state is append-only across turns)", () => {
-		const chat = chatStore.createChat("Test: persist ids");
+		const chat = chatStore.createChat("Test: persist slices the turn tail");
 		trackChat(chat.id);
-		persistTurn(chatStore, chat.id, [
+		chatStore.saveMessages(chat.id, [
-			{ id: "", role: "user", parts: [{ type: "text", text: "q" }] },
+			{ id: "base_1", role: "user", content: "first", timestamp: 1 } as never,
-			{ id: "", role: "assistant", parts: [{ type: "text", text: "a1" }] },
+		]);
-			{ id: "", role: "assistant", parts: [{ type: "text", text: "a2" }] },
+		// The agent's state at onFinish: the base record + the turn's OWN new
+		// messages (Wave B: onFinish receives the full native history — the
+		// slice keeps persist append-only).
+		const state = [
+			{ id: "base_1", role: "user", content: "first", timestamp: 1 } as never,
+			{
+				id: "",
+				role: "assistant",
+				content: [{ type: "text", text: "wake turn" }],
+				api: "openai-completions",
+				provider: "openrouter",
+				model: "test",
+				usage: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+				stopReason: "stop",
+				timestamp: 1,
+			} as never,
+		];
+		const stamped = persistTurn(chatStore, chat.id, 1, state, false);
+		assert.equal(stamped.length, 1, "only the turn's new tail persists");
+		const record = chatStore.getChat(chat.id)!;
+		assert.equal(record.messages.length, 2, "the base record is untouched — append-only");
+		assert.match(record.messages[1]!.id, /^msg_/);
+	});
+
+	it("drops clean question placeholders, keeps errored ones (fork 1: the record ends at the unanswered call)", () => {
+		const chat = chatStore.createChat("Test: persist placeholder filtering");
+		trackChat(chat.id);
+		const stamped = persistTurn(chatStore, chat.id, 0, [
+			{
+				id: "",
+				role: "assistant",
+				content: [{ type: "toolCall", id: "q1", name: "quiz", arguments: { question: "q?" } as never }],
+				api: "openai-completions",
+				provider: "openrouter",
+				model: "test",
+				usage: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+				stopReason: "toolUse",
+				timestamp: 1,
+			} as never,
+			// The loop's synthetic "question posed" result — never a fact.
+			{
+				id: "",
+				role: "toolResult",
+				toolCallId: "q1",
+				toolName: "quiz",
+				content: [{ type: "text", text: "question posed" }],
+				details: "question posed",
+				isError: false,
+				timestamp: 1,
+			} as never,
+			// An ERRORED authoring call DOES persist — the model's retry context.
+			{
+				id: "",
+				role: "toolResult",
+				toolCallId: "q1",
+				toolName: "quiz",
+				content: [{ type: "text", text: "bad options" }],
+				details: "bad options",
+				isError: true,
+				timestamp: 1,
+			} as never,
 		], false);
-		const record = chatStore.getChat(chat.id);
+		assert.equal(stamped.length, 2, "the clean placeholder is filtered, the errored result stays");
-		const ids = record!.messages.map((m) => m.id);
+		const record = chatStore.getChat(chat.id)!;
-		assert.ok(ids.every((id) => id && id.length > 0), "no empty ids survive persist");
+		assert.equal(record.messages.length, 2);
-		assert.equal(new Set(ids).size, ids.length, "ids unique — React keys safe");
+		assert.equal((record.messages[1] as { isError: boolean }).isError, true);
 	});
 });
 
@@ -1142,17 +1201,34 @@ describe("abort (src/server/jobs.ts abortJob)", () => {
 	function newChatWithResearchJob(label: string, toolCallId: string): { chatId: string; jobId: string } {
 		const chat = chatStore.createChat(`Test: ${label}`);
 		trackChat(chat.id);
+		// Native fixture — the record is agent history (Wave B).
 		chatStore.saveMessages(chat.id, [
-			{ id: "u1", role: "user", parts: [{ type: "text", text: "hi" }] },
+			{ id: "u1", role: "user", content: "hi", timestamp: 1 } as never,
 			{
 				id: "a1",
 				role: "assistant",
-				parts: [
+				content: [
 					{ type: "text", text: "Checking." },
-					{ type: "tool-research", toolCallId, state: "output-available", input: RESEARCH_INPUT, output: "Dispatched." },
+					{ type: "toolCall", id: toolCallId, name: "research", arguments: RESEARCH_INPUT as never },
 				],
-			},
+				api: "openai-completions",
-		] as never);
+				provider: "openrouter",
+				model: "test",
+				usage: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+				stopReason: "toolUse",
+				timestamp: 1,
+			} as never,
+			{
+				id: "r1",
+				role: "toolResult",
+				toolCallId,
+				toolName: "research",
+				content: [{ type: "text", text: "Dispatched." }],
+				details: "Dispatched.",
+				isError: false,
+				timestamp: 1,
+			} as never,
+		]);
 		const job = jobStore.createJob({ kind: "research", chatId: chat.id, toolCallId });
 		trackJob(job.id);
 		return { chatId: chat.id, jobId: job.id };
@@ -1161,8 +1237,8 @@ describe("abort (src/server/jobs.ts abortJob)", () => {
 	it("kills the running loop: error \"Aborted by learner\" immediately, loop unwinds silently, teacher gets the abort steer", async () => {
 		const { jobId } = newChatWithResearchJob("abort running job", "call-abort1");
 		const fired: SteerMessage[] = [];
-		setTurnRunner(async (_cid, messages) => {
+		setTurnRunner(async (_cid, input) => {
-			fired.push(messages[messages.length - 1] as SteerMessage);
+			fired.push((input as SteerInput).steer as SteerMessage);
 			return 200;
 		});
 		researchModelOverride.current = hangingModel();
@@ -1191,10 +1267,9 @@ describe("abort (src/server/jobs.ts abortJob)", () => {
 
 			await waitFor(() => fired.length > 0, 8000, "abort wake fired");
 			const last = fired[0]!;
-			assert.equal((last.metadata as { subagentResult: { aborted: boolean } }).subagentResult.aborted, true);
+			assert.equal((last.details as { aborted: boolean }).aborted, true);
 			assert.equal(last.id, `steer_${jobId}`);
-			assert.equal(last.parts.length, 2, "teacher-facing text + the data-subagent-aborted marker part — no artifact");
+			assert.equal(last.customType, "subagent-abort", "the abort marker — no artifact");
-			assert.equal(last.parts[1]!.type, "data-subagent-aborted");
 			// aborted is terminal: the wake completing must not flip it
 			assert.equal(jobStore.getJob(jobId)!.status, "error", "terminal after the wake");
 		} finally {
@@ -1231,7 +1306,7 @@ describe("abort (src/server/jobs.ts abortJob)", () => {
 	it("aborting a delivering job drops the queued result steer and wakes with the abort note instead", async () => {
 		const chat = chatStore.createChat("Test: abort delivering job");
 		trackChat(chat.id);
-		chatStore.saveMessages(chat.id, [{ id: "u1", role: "user", parts: [{ type: "text", text: "hello" }] }] as never);
+		chatStore.saveMessages(chat.id, [{ id: "u1", role: "user", content: "hello", timestamp: 1 } as never]);
 		const job = jobStore.createJob({ kind: "research", chatId: chat.id, toolCallId: "call-abort3" });
 		trackJob(job.id);
 		const result: ResearchResult = { brief: "Done: it works.", sources: [{ title: "s", url: "https://x.test" }] };
@@ -1240,8 +1315,8 @@ describe("abort (src/server/jobs.ts abortJob)", () => {
 		// Block the pump's idle gates so the result steer sits QUEUED, not in flight.
 		assert.ok(beginTurn(chat.id));
 		const fired: SteerMessage[] = [];
-		setTurnRunner(async (_cid, messages) => {
+		setTurnRunner(async (_cid, input) => {
-			fired.push(messages[messages.length - 1] as SteerMessage);
+			fired.push((input as SteerInput).steer as SteerMessage);
 			return 200;
 		});
 		void deliverJobResult(buildSubagentSteer(job, result)).catch(() => {
@@ -1257,11 +1332,7 @@ describe("abort (src/server/jobs.ts abortJob)", () => {
 		endTurn(chat.id); // gates open — whatever is left in the queue fires
 		await waitFor(() => fired.length > 0, 8000, "wake fired");
 		assert.equal(fired.length, 1, "exactly one delivery — the result steer was dropped");
-		assert.equal(
+		assert.equal((fired[0]!.details as { aborted: boolean }).aborted, true, "the abort steer, not the result");
-			(fired[0]!.metadata as { subagentResult: { aborted: boolean } }).subagentResult.aborted,
-			true,
-			"the abort steer, not the result",
-		);
 		assert.equal(jobStore.getJob(job.id)!.status, "error", "terminal after the wake");
 	});
 
@@ -1297,7 +1368,7 @@ describe("stale-job recovery sweep (liveness-gated)", () => {
 	function orphanJob(withResult?: ResearchResult): { chatId: string; jobId: string } {
 		const chat = chatStore.createChat("Test: stale sweep");
 		trackChat(chat.id);
-		chatStore.saveMessages(chat.id, [{ id: "u1", role: "user", parts: [{ type: "text", text: "hello" }] }] as never);
+		chatStore.saveMessages(chat.id, [{ id: "u1", role: "user", content: "hello", timestamp: 1 } as never]);
 		const job = jobStore.createJob({ kind: "research", chatId: chat.id, toolCallId: `call-sweep-${createdJobs.length}` });
 		trackJob(job.id);
 		if (withResult) jobStore.updateJob(job.id, { result: withResult, activity: "delivering result" });
@@ -1360,14 +1431,7 @@ describe("BYOK job refusal (no factory floor)", () => {
 	it("runJob with NO resolvable engine lands the job as error — the envelope wording, no phantom run", async () => {
 		const chat = chatStore.createChat("Test: unconfigured spawn");
 		trackChat(chat.id);
-		chatStore.saveMessages(chat.id, [
+		chatStore.saveMessages(chat.id, nativeToolMessages("hi", "research", "call-nc1", RESEARCH_INPUT));
-			{ id: "u1", role: "user", parts: [{ type: "text", text: "hi" }] },
-			{
-				id: "a1",
-				role: "assistant",
-				parts: [{ type: "tool-research", toolCallId: "call-nc1", state: "output-available", input: RESEARCH_INPUT, output: "Dispatched." }],
-			},
-		] as never);
 
 		const job = jobStore.createJob({ kind: "research", chatId: chat.id, toolCallId: "call-nc1" });
 		trackJob(job.id);
@@ -1388,9 +1452,8 @@ describe("BYOK job refusal (no factory floor)", () => {
 		assert.match(done.error ?? "", /No model configured/);
 		assert.match(done.error ?? "", /missing: cheap/);
 		assert.equal(delivery.steers.length, 1, "the refusal STEERED — the teacher is not stranded");
-		const text = delivery.steers[0]!.parts[0];
 		assert.ok(
-			text.type === "text" && text.text.includes("Research failed: No model configured"),
+			delivery.steers[0]!.content.includes("Research failed: No model configured"),
 			"the steer carries the kind's failure shape",
 		);
 		const result = done.result as ResearchResult;
@@ -1404,14 +1467,7 @@ describe("provider-key job refusal (key-presence interlude)", () => {
 	it("an engine whose provider key is gone refuses the spawn — envelope wording, no phantom run", async () => {
 		const chat = chatStore.createChat("Test: keyless spawn");
 		trackChat(chat.id);
-		chatStore.saveMessages(chat.id, [
+		chatStore.saveMessages(chat.id, nativeToolMessages("hi", "research", "call-km1", RESEARCH_INPUT));
-			{ id: "u1", role: "user", parts: [{ type: "text", text: "hi" }] },
-			{
-				id: "a1",
-				role: "assistant",
-				parts: [{ type: "tool-research", toolCallId: "call-km1", state: "output-available", input: RESEARCH_INPUT, output: "Dispatched." }],
-			},
-		] as never);
 
 		const job = jobStore.createJob({ kind: "research", chatId: chat.id, toolCallId: "call-km1" });
 		trackJob(job.id);
@@ -1441,9 +1497,8 @@ describe("provider-key job refusal (key-presence interlude)", () => {
 		assert.equal(done.error, providerKeyMissing(engine.model.provider, ["cheap"]).error, "the envelope's error line verbatim");
 		assert.deepEqual(seen, [[engine.model.provider, "cheap"]], "the check saw the engine's provider + the researcher's tier");
 		assert.equal(delivery.steers.length, 1, "the refusal STEERED — the teacher is not stranded");
-		const text = delivery.steers[0]!.parts[0];
 		assert.ok(
-			text.type === "text" && text.text.includes(`Research failed: No ${engine.model.provider} key is set`),
+			delivery.steers[0]!.content.includes(`Research failed: No ${engine.model.provider} key is set`),
 			"the steer carries the kind's failure shape",
 		);
 		const result = done.result as ResearchResult;

tests/phases.test.ts

@@ -36,7 +36,7 @@ const PLAN_OK = { ok: true, tree: { nodes: [{ id: "n1", title: "N" }], edges: []
 
 /** The verdict button's user message (the custom-message scheme): its own
  *  message carrying ONLY the data-verdict marker part — no human-authored
- *  text; the model-facing wording is the adapter's (record-adapter.ts). */
+ *  text; the model-facing wording is toLlmMessages' (native-messages.ts). */
 function verdict(accepted: boolean): UIMessage {
 	return {
 		id: `u_verdict_${Math.random().toString(36).slice(2, 6)}`,

tests/plan-blocks.test.ts

@@ -1,15 +1,20 @@
 /**
  * plan-blocks — the INTERIM plan presentation seam (docs/probe-teach-split.md
  * §6): the full block renders IN FLOW exactly once, attached to the
- * assistant message carrying the successful plan_init call. The
+ * assistant group carrying the successful plan_init call. Wave B: emission
- * neighborhood-block machinery is retired (position derives live from
+ * is a NATIVE plan-block marker (one per TURN, for the last successful
- * derivePlanStatuses); the persistent DAG window (UI wave) succeeds this.
+ * call), and the one-way projection splices its data part right after the
+ * last successful plan_init tool part. The neighborhood-block machinery is
+ * retired (position derives live from derivePlanStatuses); the persistent
+ * DAG window (UI wave) succeeds this.
  */
 import assert from "node:assert";
 import test from "node:test";
-import type { UIMessage } from "ai";
-import { withPlanBlocks, type PlanBlockPart } from "../src/core/plan-blocks.ts";
 import type { PlanTree } from "../src/core/contracts.ts";
+import type { LhMessage } from "../src/core/native-messages.ts";
+import { planBlocksFor } from "../src/core/plan-blocks.ts";
+import { projectNative } from "../src/core/projection.ts";
+import type { PlanBlockData } from "../src/core/contracts.ts";
 
 // 5-node fixture: a → b → c, b → d, d → e.
 const TREE: PlanTree = {
@@ -40,132 +45,186 @@ const TREE2: PlanTree = {
 	version: 2,
 };
 
-/** An assistant message carrying a successful plan_init with the fixture tree. */
+/** A native assistant message with one tool call (the projection's tool
-function planInitMessage(id: string, tree: PlanTree = TREE): UIMessage {
+ *  part source) — minimal fixture shape, same as the record holds. */
+function assistantWithCall(id: string, name: string, args: unknown, ...text: string[]): LhMessage {
+	const content: unknown[] = [];
+	for (const t of text) content.push({ type: "text", text: t });
+	content.push({ type: "toolCall", id: `call_${id}`, name, arguments: args as never });
 	return {
 		id,
 		role: "assistant",
-		parts: [
+		content,
-			{ type: "text", text: "Here is the plan." },
+		api: "openai-completions",
-			{ type: "tool-plan_init", state: "output-available", output: { ok: true, tree } },
+		provider: "openrouter",
-		],
+		model: "test",
-	} as unknown as UIMessage;
+		usage: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+		stopReason: "stop",
+		timestamp: Date.now(),
+	} as never;
 }
 
-/** A message built from raw parts (positional tests need exact part arrays). */
+/** A native tool result for a call (details = what the record + projection
-function msg(role: string, parts: unknown[]): UIMessage {
+ *  read; the plan tool persists {ok, tree} here). */
-	return { id: `m_${Math.random().toString(36).slice(2, 8)}`, role, parts } as unknown as UIMessage;
+function resultOf(callId: string, toolName: string, details: unknown, isError = false): LhMessage {
+	return {
+		id: `r_${callId}${isError ? "_e" : ""}`,
+		role: "toolResult",
+		toolCallId: `call_${callId}`,
+		toolName,
+		content: [{ type: "text", text: isError ? "failed" : "ok" }],
+		details,
+		isError,
+		timestamp: Date.now(),
+	} as never;
 }
 
-function blocksOf(messages: UIMessage[]): PlanBlockPart[] {
+/** Emit + persist + project: the full persistTurn slice for a turn whose
-	return messages.flatMap((m) => m.parts.filter((p) => p.type === "data-plan-block") as PlanBlockPart[]);
+ *  new messages are `turn`, run over `record`. Returns the projection of
+ *  the whole record after the write. */
+function projectAfter(record: LhMessage[], turn: LhMessage[], tree: PlanTree | null) {
+	const blocks = planBlocksFor(record, turn, tree, projectNative([...record, ...turn]));
+	return projectNative([...record, ...turn, ...blocks]);
 }
 
-test("withPlanBlocks: a successful plan_init message gains ONE full block (all nodes, statuses from the transcript)", () => {
+function blocksOf(messages: ReturnType<typeof projectNative>): PlanBlockData[] {
-	const out = withPlanBlocks([planInitMessage("m1")], TREE);
+	return messages.flatMap((m) =>
+		(m.parts as { type: string; data?: PlanBlockData }[])
+			.filter((p) => p.type === "data-plan-block")
+			.map((p) => p.data!),
+	);
+}
+
+test("a successful plan_init turn gains ONE full block (all nodes, statuses from the transcript)", () => {
+	const turn = [
+		assistantWithCall("m1", "plan_init", { tree: TREE }, "Here is the plan."),
+		resultOf("m1", "plan_init", { ok: true, tree: TREE }),
+	];
+	const out = projectAfter([], turn, TREE);
 	const blocks = blocksOf(out);
 	assert.equal(blocks.length, 1);
-	const data = blocks[0]!.data;
+	const data = blocks[0]!;
 	assert.equal(data.kind, "full");
 	assert.equal(data.current, null, "at authoring nothing is current");
 	assert.equal(data.nodes.length, 5);
 	assert.ok(data.nodes.every((n) => n.status === "upcoming"));
 	assert.equal(data.edges.length, 4);
-	// attached to the plan_init message itself
-	assert.equal(blocksOf([out[0]!]).length, 1);
 });
 
-test("withPlanBlocks: a FAILED plan_init gains nothing", () => {
+test("a FAILED plan_init gains nothing", () => {
-	const failed: UIMessage = {
+	const turn = [
-		id: "m1",
+		assistantWithCall("m1", "plan_init", { tree: TREE }, "oops"),
-		role: "assistant",
+		resultOf("m1", "plan_init", { ok: false, error: "bad" }, true),
-		parts: [
+	];
-			{ type: "text", text: "oops" },
+	assert.equal(blocksOf(projectAfter([], turn, TREE)).length, 0);
-			{ type: "tool-plan_init", state: "output-error", output: { ok: false, error: "bad" } },
-		],
-	} as unknown as UIMessage;
-	assert.equal(blocksOf(withPlanBlocks([failed], TREE)).length, 0);
 });
 
-test("withPlanBlocks: idempotent — a message that already carries a block is never given another", () => {
+test("idempotent — a call whose block the record already carries is never re-emitted", () => {
-	const once = withPlanBlocks([planInitMessage("m1")], TREE);
+	const turn = [
-	const twice = withPlanBlocks(once, TREE);
+		assistantWithCall("m1", "plan_init", { tree: TREE }),
-	assert.equal(blocksOf(twice).length, 1, "no duplicate block on persist replay");
+		resultOf("m1", "plan_init", { ok: true, tree: TREE }),
+	];
+	const first = projectAfter([], turn, TREE);
+	assert.equal(blocksOf(first).length, 1);
+	// Persist replay: the same turn's messages land again over a record
+	// that already emitted the marker → no duplicate.
+	const record: LhMessage[] = [...turn, ...planBlocksFor([], turn, TREE, projectNative(turn))];
+	const blocks2 = planBlocksFor(record, turn, TREE, projectNative(record));
+	assert.equal(blocks2.length, 0, "no duplicate block on persist replay");
 });
 
-test("withPlanBlocks: a plan REWRITE (second successful plan_init) gets its own full block; the old stays frozen", () => {
+test("a plan REWRITE (a later turn's successful plan_init) gets its own full block; the old stays frozen", () => {
-	const rewrittenTree: PlanTree = { nodes: TREE.nodes.slice(0, 3), edges: [{ from: "a", to: "b" }], version: 2 };
+	const first = [
-	const out = withPlanBlocks([planInitMessage("m1"), planInitMessage("m2", rewrittenTree)], rewrittenTree);
+		assistantWithCall("m1", "plan_init", { tree: TREE }),
+		resultOf("m1", "plan_init", { ok: true, tree: TREE }),
+	];
+	const record = [...first, ...planBlocksFor([], first, TREE, projectNative(first))];
+	const second = [
+		assistantWithCall("m2", "plan_init", { tree: TREE2 }),
+		resultOf("m2", "plan_init", { ok: true, tree: TREE2 }),
+	];
+	const out = projectAfter(record, second, TREE2);
 	const blocks = blocksOf(out);
-	assert.equal(blocks.length, 2, "one full block per authoring event");
+	assert.equal(blocks.length, 2, "one full block per authoring turn");
-	assert.equal(blocks[1]!.data.nodes.length, 3);
+	assert.equal(blocks[1]!.nodes.length, 3);
 });
 
-test("withPlanBlocks: the block renders IN FLOW immediately after the plan_init part — not appended under the turn's later parts", () => {
+test("the block renders IN FLOW immediately after the plan_init part — not appended under the turn's later parts", () => {
 	// Real-world shape (user session chat_mtwgb9lj): the authoring turn
-	// carries plan_init, then presentation prose, then quiz calls — emission
+	// carries plan_init + prose + a quiz call — emission runs at persistTurn
-	// runs at persistTurn AFTER all of that exists.
+	// AFTER all of that exists.
-	const turn = msg("assistant", [
+	const turn = [
-		{ type: "step-start" },
+		assistantWithCall("m1", "plan_init", { tree: TREE }),
-		{ type: "tool-plan_init", state: "output-available", output: { ok: true, tree: TREE } },
+		resultOf("m1", "plan_init", { ok: true, tree: TREE }),
-		{ type: "step-start" },
+		assistantWithCall("m1b", "quiz", { question: "q?" }, "Here's the plan."),
-		{ type: "text", state: "done", text: "Here's the plan." },
+		resultOf("m1", "plan_init", { ok: true, tree: TREE }), // (kept out via emitted set — see next test)
-		{ type: "tool-quiz", state: "input-available", input: { question: "q?" } },
+	];
-	]);
+	turn.pop(); // drop the stray duplicate — build the real shape below
-	const out = withPlanBlocks([turn], TREE);
+	const real = [
-	const types = out[0]!.parts.map((p) => p.type);
+		assistantWithCall("m1", "plan_init", { tree: TREE }),
-	assert.equal(types[2], "data-plan-block", "the block directly follows the plan_init part");
+		resultOf("m1", "plan_init", { ok: true, tree: TREE }),
-	assert.equal(types.indexOf("data-plan-block"), 2);
+		assistantWithCall("m1b", "quiz", { question: "q?" }, "Here's the plan."),
-	assert.ok(types.indexOf("data-plan-block") < types.indexOf("text"), "block before the prose");
+	];
-	assert.ok(types.indexOf("data-plan-block") < types.indexOf("tool-quiz"), "block before the first check");
+	const out = projectAfter([], real, TREE);
+	const group = out.find((m) => m.role === "assistant")!;
+	const types = (group.parts as unknown[]).map((p) => (p as { type: string }).type);
+	const blockAt = types.indexOf("data-plan-block");
+	assert.ok(blockAt > types.indexOf("tool-plan_init"), "the block directly follows the plan_init part");
+	assert.ok(blockAt < types.indexOf("text"), "block before the prose");
+	assert.ok(blockAt < types.indexOf("tool-quiz"), "block before the first check");
 	assert.equal(types.at(-1), "tool-quiz", "the quiz is still the turn's last part");
 });
 
-test("withPlanBlocks: with multiple plan_inits in one turn (a rewrite), the block follows the LAST one", () => {
+test("with multiple plan_inits in one turn (a same-turn rewrite), ONE block follows the LAST one", () => {
-	const turn = msg("assistant", [
+	const turn = [
-		{ type: "tool-plan_init", state: "output-available", output: { ok: true, tree: TREE } },
+		assistantWithCall("m1", "plan_init", { tree: TREE }, "v1"),
-		{ type: "text", state: "done", text: "v1" },
+		resultOf("m1", "plan_init", { ok: true, tree: TREE }),
-		{ type: "tool-plan_init", state: "output-available", output: { ok: true, tree: TREE2 } },
+		assistantWithCall("m2", "plan_init", { tree: TREE2 }, "v2"),
-		{ type: "text", state: "done", text: "v2" },
+		resultOf("m2", "plan_init", { ok: true, tree: TREE2 }),
-	]);
+	];
-	const out = withPlanBlocks([turn], TREE2);
+	const out = projectAfter([], turn, TREE2);
-	const types = out[0]!.parts.map((p) => p.type);
+	const group = out.find((m) => m.role === "assistant")!;
-	assert.equal(types[3], "data-plan-block", "block directly after the last successful init");
+	const parts = group.parts as unknown[];
-	assert.equal(types[4], "text", "the trailing prose stays after the block");
+	const blocks = parts.filter((p) => (p as { type: string }).type === "data-plan-block");
-	assert.equal(out[0]!.parts.filter((p) => p.type === "data-plan-block").length, 1, "one block per message even on a same-turn rewrite");
+	assert.equal(blocks.length, 1, "one block per turn even on a same-turn rewrite");
+	const types = parts.map((p) => (p as { type: string }).type);
+	assert.ok(
+		types.indexOf("data-plan-block") > types.indexOf("tool-plan_init"),
+		"the block follows the last successful init",
+	);
 });
 
-test("withPlanBlocks: quizzes alone emit nothing (no neighborhood blocks anymore)", () => {
+test("quizzes alone emit nothing (no neighborhood blocks anymore)", () => {
-	const quizTurn: UIMessage = {
+	const turn = [
-		id: "m1",
+		assistantWithCall("m1", "quiz", { nodeId: "b", question: "q?" }),
-		role: "assistant",
+		resultOf("m1", "quiz", { correct: true }),
-		parts: [
+	];
-			{ type: "text", text: "check" },
+	assert.equal(blocksOf(projectAfter([], turn, TREE)).length, 0);
-			{ type: "tool-quiz", state: "output-available", input: { nodeId: "b" }, output: { correct: true } },
-		],
-	} as unknown as UIMessage;
-	assert.equal(blocksOf(withPlanBlocks([quizTurn], TREE)).length, 0);
 });
 
-test("withPlanBlocks: no tree / empty tree / no messages are no-ops", () => {
+test("no tree / empty tree / no messages are no-ops", () => {
-	assert.equal(withPlanBlocks([planInitMessage("m1")], null).length, 1, "passthrough");
+	const turn = [
+		assistantWithCall("m1", "plan_init", { tree: TREE }),
+		resultOf("m1", "plan_init", { ok: true, tree: TREE }),
+	];
+	assert.equal(planBlocksFor([], turn, null, []).length, 0, "no tree → nothing");
 	const emptyTree: PlanTree = { nodes: [], edges: [], version: 0 };
-	assert.equal(blocksOf(withPlanBlocks([planInitMessage("m1")], emptyTree)).length, 0);
+	assert.equal(planBlocksFor([], turn, emptyTree, []).length, 0, "empty tree → nothing");
-	assert.equal(withPlanBlocks([], TREE).length, 0);
+	assert.equal(planBlocksFor([], [], TREE, []).length, 0, "no messages → nothing");
 });
 
-test("withPlanBlocks: mid-lesson rewrite snapshot derives statuses from the whole transcript", () => {
+test("mid-lesson rewrite snapshot derives statuses from the whole transcript", () => {
 	// A tagged quiz call on node b happened before the rewrite: b is current.
-	const quizBefore: UIMessage = {
+	const before = [
-		id: "m0",
+		assistantWithCall("m0", "quiz", { nodeId: "b", question: "q?" }),
-		role: "assistant",
+		resultOf("m0", "quiz", { correct: true }),
-		parts: [
+	];
-			{ type: "text", text: "about b" },
+	const rewrite = [
-			{ type: "tool-quiz", state: "output-available", input: { nodeId: "b" }, output: { correct: true } },
+		assistantWithCall("m1", "plan_init", { tree: TREE }),
-		],
+		resultOf("m1", "plan_init", { ok: true, tree: TREE }),
-	} as unknown as UIMessage;
+	];
-	const out = withPlanBlocks([quizBefore, planInitMessage("m1")], TREE);
+	const out = projectAfter(before, rewrite, TREE);
-	const data = blocksOf(out)[0]!.data;
+	const data = blocksOf(out)[0]!;
 	assert.equal(data.current, "b");
 	const b = data.nodes.find((n) => n.id === "b")!;
 	assert.equal(b.status, "current");

tests/probe-done.test.ts

@@ -3,13 +3,18 @@
  * Server-side; three outcomes: refusal while a question is open, refusal
  * after the probe is already concluded, ok + handoff queued. The handoff
  * rides the wake pipeline (deliver injected here — no server seam import).
+ * Wave B: the record is native history — fixtures are pi messages, the
+ * pending-question gate is the dangling-question scan, and the handoff is
+ * a native marker (customType probe-handoff, HANDOFF_TEXT content).
  */
 import assert from "node:assert/strict";
 import * as fs from "node:fs";
 import * as path from "node:path";
 import { after, describe, it } from "node:test";
 import { probeDoneTool } from "../src/agent/tools/probe.ts";
-import type { ProbeHandoffSteerMessage } from "../src/core/contracts.ts";
+import type { SteerMessage } from "../src/core/contracts.ts";
+import type { LhMessage } from "../src/core/native-messages.ts";
+import { HANDOFF_TEXT } from "../src/core/contracts.ts";
 import { chatStore } from "../src/store/chats.ts";
 import { PATHS } from "../config.ts";
 
@@ -40,6 +45,22 @@ const ASSESSMENT = {
 	summary: "Enter at the formal definition.",
 };
 
+/** A native assistant message carrying one tool call (the minimal fixture
+ *  shape the scans read — role assistant, content blocks). */
+function assistantWithCall(id: string, toolName: string, args: unknown): LhMessage {
+	return {
+		id,
+		role: "assistant",
+		content: [{ type: "toolCall", id: `call_${id}`, name: toolName, arguments: args as never }],
+		api: "openai-completions",
+		provider: "openrouter",
+		model: "test",
+		usage: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+		stopReason: "stop",
+		timestamp: Date.now(),
+	} as never;
+}
+
 async function execute(tools: ReturnType<typeof probeDoneTool>, input: unknown) {
 	const t = tools.probe_done!;
 	assert.ok(typeof t.execute === "function");
@@ -49,7 +70,7 @@ async function execute(tools: ReturnType<typeof probeDoneTool>, input: unknown)
 describe("probe_done: the probe→planning seam", () => {
 	it("ok path: records the assessment and queues the handoff steer (deterministic id)", async () => {
 		const chatId = newChat("Probe: ok");
-		const delivered: ProbeHandoffSteerMessage[] = [];
+		const delivered: SteerMessage[] = [];
 		const tools = probeDoneTool({ chatId, chatStore, deliver: (s) => delivered.push(s) });
 
 		const res = await execute(tools, { assessment: ASSESSMENT });
@@ -57,19 +78,19 @@ describe("probe_done: the probe→planning seam", () => {
 		assert.equal(res.error, undefined);
 		assert.equal(delivered.length, 1, "the handoff is queued exactly once");
 		assert.equal(delivered[0]!.id, `steer_probe_${chatId}`);
-		assert.equal((delivered[0]!.metadata as { probeHandoff: { chatId: string } }).probeHandoff.chatId, chatId);
+		// Native marker (Wave B): the model-facing HANDOFF_TEXT rides content;
+		// the UI keys off customType; the chat id rides details.
+		assert.equal(delivered[0]!.customType, "probe-handoff");
+		assert.equal(delivered[0]!.content, HANDOFF_TEXT);
+		assert.equal((delivered[0]!.details as { chatId: string }).chatId, chatId);
 	});
 
 	it("REFUSES while a question is still open — resolve it first", async () => {
 		const chatId = newChat("Probe: open question");
 		chatStore.saveMessages(chatId, [
-			{
+			assistantWithCall("m1", "quiz", { question: "q?", options: [{ label: "a" }], correctAnswer: "a" }),
-				id: "m1",
-				role: "assistant",
-				parts: [{ type: "tool-quiz", state: "input-available", input: { question: "q?" } }],
-			} as never,
 		]);
-		const delivered: ProbeHandoffSteerMessage[] = [];
+		const delivered: SteerMessage[] = [];
 		const tools = probeDoneTool({ chatId, chatStore, deliver: (s) => delivered.push(s) });
 
 		const res = await execute(tools, { assessment: ASSESSMENT });
@@ -81,13 +102,18 @@ describe("probe_done: the probe→planning seam", () => {
 	it("REFUSES a second conclusion — probe_done fires exactly once", async () => {
 		const chatId = newChat("Probe: twice");
 		chatStore.saveMessages(chatId, [
+			assistantWithCall("m1", "probe_done", { assessment: ASSESSMENT }),
 			{
-				id: "m1",
+				id: "m1r",
-				role: "assistant",
+				role: "toolResult",
-				parts: [{ type: "tool-probe_done", state: "output-available", input: { assessment: ASSESSMENT }, output: { ok: true } }],
+				toolCallId: "call_m1",
+				toolName: "probe_done",
+				content: [{ type: "text", text: "ok" }],
+				isError: false,
+				timestamp: Date.now(),
 			} as never,
 		]);
-		const delivered: ProbeHandoffSteerMessage[] = [];
+		const delivered: SteerMessage[] = [];
 		const tools = probeDoneTool({ chatId, chatStore, deliver: (s) => delivered.push(s) });
 
 		const res = await execute(tools, { assessment: ASSESSMENT });

tests/reattach-transport.test.ts

@@ -18,6 +18,10 @@
 import assert from "node:assert/strict";
 import { afterEach, describe, it } from "node:test";
 import { createReattachingTransport } from "../components/chat-transport.ts";
+import type { ChatInput } from "../src/core/input-events.ts";
+
+/** A no-op input-events stash (the reattach tests never send). */
+const NO_INPUT = { takeInput: () => undefined };
 
 const realFetch = globalThis.fetch;
 afterEach(() => {
@@ -67,7 +71,7 @@ describe("reattach transport (reconnectToStream)", () => {
 			urls.push(String(input));
 			return dripped(sse({ type: "start", messageId: "msg_run_1" }), 8);
 		}) as typeof globalThis.fetch;
-		const transport = createReattachingTransport("chat_x", {});
+		const transport = createReattachingTransport("chat_x", {}, NO_INPUT);
 		await collect((await transport.reconnectToStream(RECONNECT_OPTS))!);
 		assert.deepEqual(urls, ["/api/chats/chat_x/stream"]);
 	});
@@ -76,7 +80,7 @@ describe("reattach transport (reconnectToStream)", () => {
 		globalThis.fetch = (async () =>
 			dripped(sse({ type: "turn-settled" }, "[DONE]"), 8)) as typeof globalThis.fetch;
 		let settled = 0;
-		const transport = createReattachingTransport("chat_x", { onSettled: () => settled++ });
+		const transport = createReattachingTransport("chat_x", { onSettled: () => settled++ }, NO_INPUT);
 		const stream = await transport.reconnectToStream(RECONNECT_OPTS);
 		assert.equal(stream, null);
 		assert.equal(settled, 1);
@@ -86,7 +90,7 @@ describe("reattach transport (reconnectToStream)", () => {
 
 	it("204 (the SDK's native no-stream signal) resolves null untouched", async () => {
 		globalThis.fetch = (async () => new Response(null, { status: 204 })) as typeof globalThis.fetch;
-		const transport = createReattachingTransport("chat_x", {});
+		const transport = createReattachingTransport("chat_x", {}, NO_INPUT);
 		assert.equal(await transport.reconnectToStream(RECONNECT_OPTS), null);
 	});
 
@@ -102,7 +106,7 @@ describe("reattach transport (reconnectToStream)", () => {
 				),
 				13,
 			)) as typeof globalThis.fetch;
-		const transport = createReattachingTransport("chat_x", {});
+		const transport = createReattachingTransport("chat_x", {}, NO_INPUT);
 		const chunks = (await collect((await transport.reconnectToStream(RECONNECT_OPTS))!)) as Array<
 			Record<string, unknown>
 		>;
@@ -120,7 +124,7 @@ describe("reattach transport (reconnectToStream)", () => {
 			)) as typeof globalThis.fetch;
 		const transport = createReattachingTransport("chat_x", {
 			lastMessageId: () => "msg_seed",
-		});
+		}, NO_INPUT);
 		const chunks = (await collect((await transport.reconnectToStream(RECONNECT_OPTS))!)) as Array<
 			Record<string, unknown>
 		>;
@@ -134,7 +138,7 @@ describe("reattach transport (reconnectToStream)", () => {
 	it("survives a body split byte-by-byte across reads", async () => {
 		globalThis.fetch = (async () =>
 			dripped(sse({ type: "start", messageId: "msg_run_1" }, { type: "finish", finishReason: "stop" }), 1)) as typeof globalThis.fetch;
-		const transport = createReattachingTransport("chat_x", {});
+		const transport = createReattachingTransport("chat_x", {}, NO_INPUT);
 		const chunks = (await collect((await transport.reconnectToStream(RECONNECT_OPTS))!)) as Array<
 			Record<string, unknown>
 		>;
@@ -147,7 +151,7 @@ describe("reattach transport (reconnectToStream)", () => {
 
 	it("an unhappy endpoint throws (the SDK surfaces the error banner)", async () => {
 		globalThis.fetch = (async () => new Response("boom", { status: 500 })) as typeof globalThis.fetch;
-		const transport = createReattachingTransport("chat_x", {});
+		const transport = createReattachingTransport("chat_x", {}, NO_INPUT);
 		await assert.rejects(() => transport.reconnectToStream(RECONNECT_OPTS), /boom/);
 	});
 });

tests/record-adapter.test.ts

@@ -1,89 +0,0 @@
-/**
- * Unit tests — the record→pi adapter's SYSTEM MESSAGE flattening (the
- * custom-message scheme, user-decided 2026-09-12).
- *
- * Wake and verdict messages are user-role messages carrying ONLY a marker
- * data part — no human text exists. The adapter owns their model-facing
- * wording (flattens the marker to the canonical text from core contracts):
- * the transcript never persists fake human speech, and the wording can't
- * drift between the seam, the tests, and reality.
- */
-
-import assert from "node:assert/strict";
-import { describe, it } from "node:test";
-import type { UIMessage } from "ai";
-import { recordToPiMessages } from "../src/server/pi/record-adapter.ts";
-import { HANDOFF_TEXT, verdictText } from "../src/core/contracts/chat.ts";
-import { buildAbortSteer, buildProbeHandoffSteer } from "../src/core/contracts/jobs.ts";
-
-function userText(text: string): UIMessage {
-	return { id: `u_${text.length}`, role: "user", parts: [{ type: "text", text }] };
-}
-
-function userParts(parts: unknown[]): UIMessage {
-	return { id: "u_sys", role: "user", parts: parts as UIMessage["parts"] };
-}
-
-const texts = (msgs: ReturnType<typeof recordToPiMessages>): string[] => {
-	const out: string[] = [];
-	for (const m of msgs) {
-		if (m.role === "user") {
-			for (const c of m.content) {
-				if ((c as { type?: string }).type === "text") out.push((c as { text: string }).text);
-			}
-		}
-	}
-	return out;
-};
-
-describe("record-adapter: system message flattening", () => {
-	it("an ACCEPT verdict flattens to the canonical model-facing text (no human speech persisted)", () => {
-		const out = recordToPiMessages([
-			userText("teach me"),
-			userParts([{ type: "data-verdict", id: "vd_1", data: { accepted: true, at: "…" } }]),
-		]);
-		assert.deepEqual(texts(out), ["teach me", verdictText(true)]);
-		assert.equal(texts(out)[1], "The learner accepted the plan — begin teaching.");
-	});
-
-	it("a DECLINE verdict flattens to the canonical revision text", () => {
-		const out = recordToPiMessages([
-			userParts([{ type: "data-verdict", id: "vd_2", data: { accepted: false, at: "…" } }]),
-		]);
-		assert.deepEqual(texts(out), [verdictText(false)]);
-		assert.match(texts(out)[0]!, /revised/);
-	});
-
-	it("the probe handoff steer flattens to the canonical plan-authoring instruction", () => {
-		const handoff = buildProbeHandoffSteer("chat_x");
-		assert.equal(handoff.parts.length, 1, "the handoff is marker-ONLY — no text part");
-		assert.equal(handoff.parts[0]!.type, "data-probe-handoff");
-		const out = recordToPiMessages([handoff]);
-		assert.deepEqual(texts(out), [HANDOFF_TEXT]);
-		assert.match(texts(out)[0]!, /plan_init/);
-	});
-
-	it("note + verdict (the two-message accept) reach the model as two user texts, in order", () => {
-		const out = recordToPiMessages([
-			userText("Start with the basics, skip the history."),
-			userParts([{ type: "data-verdict", id: "vd_3", data: { accepted: true, at: "…" } }]),
-		]);
-		assert.deepEqual(texts(out), ["Start with the basics, skip the history.", verdictText(true)]);
-	});
-
-	it("sub-agent steers keep their text (payload, not boilerplate): the artifact part adds nothing", () => {
-		const abort = buildAbortSteer({ id: "j1", kind: "research", toolCallId: "c1" });
-		const out = recordToPiMessages([abort]);
-		const got = texts(out);
-		assert.equal(got.length, 1, "one user text — the marker part is UI-only");
-		assert.match(got[0]!, /aborted/i);
-	});
-
-	it("a pure UI data part with no system meaning still never reaches the model", () => {
-		const out = recordToPiMessages([
-			userParts([{ type: "data-plan-block", id: "pb", data: { kind: "full", at: "…", current: null, nodes: [], edges: [] } }]),
-		]);
-		assert.equal(out.length, 0, "no model face at all — skipped");
-	});
-
-});

tests/usage.test.ts

@@ -221,8 +221,11 @@ test("appendTurnUsage: appends, idempotent per turn id, continuation turns (same
 	let reread = chatStore.getChat(record.id);
 	assert.equal(reread?.turns?.length, 2);
 
-	// saveMessages must not clobber the log (read-mutate-write record)
+	// saveMessages must not clobber the log (read-mutate-write record) —
-	chatStore.saveMessages(record.id, [{ id: "msg_a", role: "user", parts: [] }]);
+	// Wave B: a NATIVE message list (the record holds agent history).
+	chatStore.saveMessages(record.id, [
+		{ id: "msg_a", role: "user", content: "native", timestamp: Date.now() } as never,
+	]);
 	reread = chatStore.getChat(record.id);
 	assert.equal(reread?.turns?.length, 2);