Diagnosis from the real 25-file notes import (user-pasted session logs):
almost every run hit 'Validation failed for tool submit_findings/review:
edges must have required properties edges' — the model (glm flash, low
thinking) omits top-level fields when they're empty, and pi-ai's
structural JSON-Schema validation runs BEFORE the zod layer, so each
omission cost one of the extractor's maxTurns 4 (full payload
regeneration) and occasionally burned out the run entirely (the two
FAILED imports).
The model is technically wrong, but the schema provokes it:
required-but-usually-empty arrays are a known weak-model anti-pattern.
- lhTool's model-facing declaration now converts with io: "input"
(the declaration describes what the MODEL sends): .default() fields
drop out of required. No-op for teacher tools (none use defaults).
- findingsSchema.edges / auditSchema.dropped: .default([]) — omission
means "none"; attribution: .default({quiz:{}}) for quiz-free sessions.
- Prompts hardened in all three agents: include every top-level field,
never omit because empty.
Structural probe: validateToolArguments now passes the exact pasted
failure shape; zod re-parse in execute applies the defaults. 355/355
tests, typecheck, lint, build green. (lh-tool.ts is the shared engine
seam — flagged to master: io:"input" is the correct mode for every
model-facing declaration, teacher path verified unaffected.)
Live observation (modal-realism run): the teacher batched two quizzes in
one turn; the dock showed the SECOND question first, so the answering
order was reversed vs the saved record and the transcript cards.
Cause: findPending scanned parts BACKWARD within a message, so with two
input-available quizzes it picked the last one first. No overwriting was
involved — parts are created in call order on both wire and record; the
scan direction alone reversed the interaction order. (pi executes a
parallel batch with starts + result messages in call order; the
execution-end order is completion-racy, which also allowed a millisecond
dock-subject flip mid-turn.)
Fix A — src/core/pending.ts: parts now scan FORWARD within a message
(messages stay newest-first): the FIRST unanswered question is the dock
subject; the second appears only after the first is answered.
Fix B — src/agent/lh-tool.ts: question tools opt into sequential
execution (pi runs the batch in call order when any called tool opts
in), so tool-input-available chunks always arrive in call order and the
dock subject can never flip mid-turn. Question executes are instant.
Pinned in chat-flow.test.ts: a parallel two-quiz batch asserts wire
order (A's available chunk before B's), part persistence order, and the
dock selection sequence (A first, then B after A is answered).
Gates: tsc, lint, build, 307/307.
The Vercel AI SDK survives only as Band D (useChat client + UIMessage
record types); @openrouter/ai-sdk-provider is uninstalled.
- src/agent/models.ts: PiEngine {model, streamFn} via createModels +
openrouterProvider subpath; thinkingLevelFor maps config effort none->off
- src/agent/lh-tool.ts: neutral LhTool (zod authoring, optional execute,
clientQuestion flag); toPiTool converts via z.toJSONSchema and re-runs
zod inside execute so refinements ride the error-result retry path
- src/server/pi/record-adapter.ts: UIMessage records -> pi Messages
(dangling tool calls get synthesized interrupted results)
- src/server/pi/ui-stream.ts: SSE bridge emitting AI-SDK-shaped chunks so
the useChat client parses unchanged (continuation id rule, question
tools never emit output, tool-input-error for bad authoring)
- teacher-agent.ts: stateless per-turn pi Agents; shouldStopAfterTurn
stops only when every question-tool call resolved cleanly (errors retry)
- chat-handler.ts: buildAgent(outgoing) factory seam (stateless doctrine);
assertValidUiMessages owns the retired SDK validation gate
- sub-agents via shared runSubagent (pi-run.ts); extraction stages stop
after a clean submit; visual-maker keeps its hand-rolled loop over
direct streamSimple calls; aborted model calls bill no usage
- tests: all model seams ported to pi-ai faux provider (scripted
FauxResponseSteps, agent factories); handleChatRequest second param
is now an agent factory
Gates: tsc, lint, build, 305/305. Live GLM smoke (disposable driver,
deleted): prober streaming + persistence, question seam, turn-2
continuation same message id, per-turn real token usage - ALL PASS.
Data wiped at the pivot (chats/graph/jobs, .gitkeeps kept).
amosblomqvist