The model-control wave (user-decided design, 2026-09-12): ONE controller
for the conversation agents (prober/teacher are functionally one agent);
background sub-agents stay config-pinned. pi-ai owns the registry — the
shipped 366-model OpenRouter catalog (cost, context, modality,
thinkingLevelMap), getSupportedThinkingLevels/clampThinkingLevel for the
per-model thinking truth, and streamSimple's automatic clamp. No second
registry to drift out of sync.
Seams:
- config.ts: ReasoningEffort retired for pi's ThinkingLevel
(off|minimal|low|medium|high|xhigh|max). GLM roles go honest at "low" —
pi's catalog says GLM-5.3-flash accepts exactly low|high|max, and the old
"minimal" was silently clamped to low by streamSimple since the swap;
nothing changes behaviorally. visualMaker → qwen/qwen3.8-flash (fixes
the dead qwen/qwen3.8-max slug — the catalog only ships -0902; also the
user's cost pick, 0.15/0.47 per-1M).
- src/agent/models.ts: piEngineFor(role, settings?) — provider+id resolved
from the catalog, thinking level from settings ?? config, CLAMPED to the
model's supported list (a settings change between models can never send
an invalid level). PiEngine gains `level` (observability/tests).
- ChatRecord.settings {model?: {provider, id}, thinkingLevel?} — written
by PUT /api/chats/[id]/settings (replace-whole, no updatedAt churn),
read by chat-handler at turn composition: agents are stateless per turn,
so the change is next-turn-effective by construction. The turns log
still records the ACTUAL billed model (the honest witness).
- GET /api/models: the configured-provider catalog as client-safe DTOs
(core/contracts/models.ts) + config defaults; a second provider joins
the picker by registering it in piModels() — nothing else changes.
- PUT settings validation gate (src/server/model-catalog.ts): unknown
provider/model or unsupported level → 400 carrying the supported list,
never a silent clamp.
- scripts/sync-pricing.ts: regenerated PRICES/CONTEXT_LIMITS from pi-ai's
shipped openrouter.json (offline; same source as the engine + picker).
All 366 models priced; glm's stale 0.15/0.5 → pi's 0.075/0.25, limit
1310720 → 1048576 — cost is inferred at read time, so history re-prices.
- UI (components/model-picker.tsx): stats-bar right side becomes model +
thinking buttons; menus open ABOVE; fuzzy search over "provider id
name" (core/fuzzy.ts — pi's /model pattern); model rows show name/id/
price/context; the thinking menu lists exactly the chosen model's
supported levels (GLM: low|high|max — no dead options, no "off").
Model switch drops an incompatible pinned level (falls back to config,
which clamps honestly) rather than carrying a 400.
Tests (350/350, +15): catalog projection + defaults, the settings gate,
pi thinking truth pinned against upgrades (glm low|high|max; minimal→low;
off→low — GLM cannot disable thinking), the engine factory's
override/fallback/clamp/throw matrix, fuzzy ranking, store round-trip,
and the re-priced folds (usage, stats bar, activity dock).
Live smoke (disposable driver, deleted): catalog route 366 + defaults;
glm+minimal → 400 + supported; turn 1 billed qwen/qwen3.8-flash under
the override; mid-session switch flipped turn 2 to glm; clear-overrides
restored the config pin. ALL CHECKS PASS on real OpenRouter.
- core/phases.ts: Phase3 (probe/plan/teach) + pure derivations —
phaseOfTree (point-in-time, from the stored plan tree: no nodes → probe,
no occupied node → plan, occupied → teach) and phaseAt3 (monotonic
transcript fold for the dividers: failed plan_init never marks a seam;
phase only advances).
- contracts.ts: ChatSummary gains record-derived phase + pendingQuestion;
ChatListItem adds liveness-merged busy.
- store/chats.ts listChats computes the record-derived fields (tree +
pending question scan).
- api/chats route merges busy = turn running || running background job.
Lane crossing granted by master: contracts/store/api (schema arbitration).
Data-only inference: pre-plan planning reads as probe until the plan lands.
The bug: answering a quiz and navigating away mid-turn, then returning,
re-prompted the same question. Root causes: (1) the answer was durable only
at onFinish — every mid-turn view read the stale pre-answer record;
(2) the server had no notion of a turn in flight; (3) remount treated the
stale record as current, with no re-attach path. Worse, the stale dock let
the quiz be answered again, racing two turns into a last-writer-wins
saveMessages clobber.
Fix (four pieces):
- Write-ahead persist in chat-handler: the request body IS the client's
canonical state — saved to disk BEFORE the stream starts. The answer is
durable the instant the request arrives; crashes recover via the existing
mount continuation.
- Turn liveness registry (src/server/turn-liveness.ts): in-memory chatId →
in-flight map with a TTL leak guard; beginTurn rejects concurrent turns
(409) so one turn ever owns a chat. endTurn runs in onFinish AFTER
persistTurn, so pollers that see not-in-flight always read a finished
record; a turn-start failure clears the registry (no lockout).
- GET /api/chats/[id] reports turnInFlight; the chat page passes
initiallyInFlight to the client.
- Client re-attach (components/chat.tsx): while in flight, busy shimmer +
composer gated + mount continuation suppressed; poll /api/chats/[id] until
the turn finishes, then syncFromServer adopts the completed transcript.
Stop stays local-stream only (a server turn has no client request to
abort).
Verified by scripted-model tests: concurrent turn 409 + registry lifecycle,
write-ahead durability mid-turn, failed-turn lockout guard.
The shell now imports through exactly two barrels, enforced by
import/no-restricted-paths (npm run lint):
components/** -> "@/src/core" (pure core API, browser-safe)
app/** -> "@/src/core" + "@/src/server" (server entries)
Zone violations are lint errors with architecture-pointer messages; the
pure-core modules (contracts, question-core, plan-tree, phases, pending,
math-delims, ui-message) may never import agent/server/store.
Supporting moves (direction: IO layers -> core):
- core/index.ts: the core public API barrel
- core/ui-message.ts: moved from src/agent (it was shell-facing all along)
- quiz/ask input zod schemas moved agent/tools -> core/question-core
(the question contract, alongside the grading logic)
- ChatRecord/ChatSummary moved store/chats -> core/contracts (single schema)
- GraphSnapshot/NodeStateClass moved core/graph -> core/contracts (the
/api/graph payload IS a contract; the pure renderer needs only these)
- src/server/{chats,graph,jobs}.ts + index.ts: thin server entries for the
transport layer; GET /api/graph's fold side-effect now lives behind
graphView() instead of inline in the route
Gates: tsc clean, 190/190 tests, eslint clean (law verified to fire on
store/agent/subpath violations), production build clean.
(Repo repair en route: a git object (app/chat/[id] tree) was missing from
the object store — reconstructed byte-exactly via mktree from its blob;
the broken node_modules that stalled the build was cleanly reinstalled.)
The teaching agent no longer runs on pi. Stack:
- ToolLoopAgent (ai@7) + OpenRouter (OPENROUTER_API_KEY), model via LH_MODEL,
default anthropic/claude-sonnet-4.5 with reasoning tokens
- quiz/ask_user_question = client-side tools (no server execute): the call
lands as a typed tool part in input-available state; the card grades via
src/core/question-core.ts; addToolOutput sends the verdict; the teacher's
reaction continues the same assistant message
- resume-mid-quiz is free: the pending tool part persists in the transcript
- persistence: one JSON per chat (data/chats/), full UIMessage transcripts,
saved onFinish (also on abort)
- UI: AI Elements (owned copy-paste components, pruned to the five in use)
+ button-based QuizCard/AnsweredCard (ask answers never graded)
- pi fully removed: TUI, extensions, Fastify+WS server, bridge, custom
protocol all deleted (recoverable from git history)
- tests: question-core units carry over; chat-flow integration drives
handleChatRequest with MockLanguageModelV4 (48 tests, zero tokens);
render smoke tests guard the cards (renderToStaticMarkup)
Carried over unchanged: teacher system prompt, question-core, schema/
ledger/derive/extract pipeline, data model.
amosblomqvist