One engine owns the equilibrium: the merge settle and (next commit)
the live drag both run createGraphSimulation — d3-force link springs,
1/d charge, weak centroid gravity — so a drag's rest state IS the
server's rest state. The FA2-era anchor mechanism survives as a
post-tick POSITION-SPACE re-blend (retention 0.85): d3's forceLink is
a Hooke spring (strength*(d-L)*alpha), which overpowers any force-space
anchor at long range — the re-blend is alpha-independent and always
wins as the sim anneals (the 675-unit drift bug). Gravity retuned for
d3's 1/d many-body falloff (bootstrap 0.2 / incremental 0.12: cluster
spacing lands ~400 world units, the FA2-era density). Rim orphans seed
(and anchor) at 1.7x the CONNECTED core's mean radius — a max-span-based
rim fed back on itself and ran the layout away to 6000 units. Replay:
338 positions in 1.6s, old-node shift within a batch 4.8 (FA2: 23).
Implements Option B from docs/research/graph-rendering.md. sigma.js v3
(WebGL) is replaced by one canvas, one rAF loop with a dirty flag, and
d3-zoom for the camera — eliminating the entire bug class from the
sigma-era bolt-on architecture:
- Hull/node desync during pan (two independent render loops) is now
structurally impossible: hull fills, dashed hull strokes, edges with
arrowheads, node discs, region labels, node labels, and hover glow
are all drawn in ONE frame under ONE camera.
- The settings-change canvas-sizing race (everything shifting up-left)
is gone: settings changes only redraw; the canvas and camera persist
(verified live: camera identical to 15 decimals across a slider drag).
- The GPU floor is gone: idle schedules NO frames at all (verified via
pixel-identity over 600ms idle); pan redraws exactly once per frame.
components/graph-canvas.ts: GraphCanvasRenderer class plus pure helpers
(zoomRatioOf, labelAlpha, fitTransform, arrowGeometry, pickNearest).
The sigma camera-ratio convention (1 = fit, smaller = zoomed in) is kept
verbatim so persisted labelZoom settings survive the swap; node labels
and cluster region labels cross-fade over the same LABELS_FADE_SPAN
(0.5, unchanged). Picking is a nearest-node distance check with the
10px pad that replaces the old padded-picking vertex shader. Hull math
stays in components/cluster-geometry.ts, reused as-is. No ctx.filter,
ever.
graph-view.tsx keeps every feature: fetch/refetch on runs-empty, FA2
run-then-freeze layout, localStorage render settings + sanitizers,
search filtering with edge drops and card-close, detail card with
flipped anchoring and per-source provenance, settings panel, import
button, pipeline status chips. Only the renderer plumbing changed.
tests/graph-canvas.test.ts pins the pure math: ratio direction, label
gate + inverse complement (alphas sum to 1), fit transform padding,
arrowhead tip-on-disc-edge and symmetry, picking pad/ties/null cases.
Live-verified end-to-end on the real 338-node graph (dev server
port 3002): single canvas, paint at fit, hover cursor+glow+fade, click
card open/anchored/close, stage click, search filter to zero with hint,
label gate opens via slider and zoom, cluster-labels toggle, zoom-to-
cursor 0.56px anchor drift, camera persistence across settings, zero
idle repaints. sigma dependency removed from package.json; d3-zoom and
d3-selection added.
Note: the settings feed effect needed isEmpty in its deps — without it
the renderer mounted with settings=null and every draw early-returned
(blank canvas); caught live, not by typecheck.
detectCommunities(nodes, edges) in src/core/clusters.ts (new dep
graphology-communities-louvain): Louvain modularity over the undirected,
unweighted follows+supports structure (user-decided 2026-09-13). The
random-walk traversal runs on an inlined seeded mulberry32 so the same
graph always yields the same partition; community indices are still
unstable across edits, which is exactly why labelings (phase B) key to
sorted MEMBER SETS. follows+supports between the same pair collapse to
one edge; self-loops and dangling edges are skipped defensively; no
min-size filter here (the >=3 render threshold is a presentation rule).
Tests: two-cliques-plus-bridge split, determinism, singleton/empty
graphs, pair collapse, defensive skips, member sorting. 363/363.
Real-data smoke over the current notes graph: 338 nodes / 211 edges ->
138 communities, modularity 0.95, and the big ones are exactly the
learn-session topics (databases, differential forms, sales, servers,
vim, copulas...). 32 communities clear the >=3 render threshold.
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).
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.)
- src/store/jobs.ts: per-job JSON store in data/jobs (create/get/update/list,
dedup by toolCallId)
- src/agent/tools/jobs.ts: research tool — client-side (no execute), turn ends
at the call; input per contracts ResearchToolInput
- src/agent/tools/web.ts: server-side web_search (Google CSE) + web_fetch
(Readability/Turndown/linkedom, Jina fallback) — errors return as strings,
never thrown into the agent loop. Deps: @mozilla/readability, linkedom,
turndown (+@types/turndown dev)
- src/agent/subagents/researcher.ts: isolated ToolLoopAgent (web tools only,
12-step cap), researcher prompt ported from pi
- src/agent/subagents/runner.ts: spawnPendingJobs hook + runResearchJob —
fire-and-forget, activity line per tool call, fulfills the part in the
LATEST chat record (output-available) before flipping job status; failure
still fulfills the part so the teacher learns the outcome
- src/server/chat-handler.ts: onFinish spawn hook after saveMessages
- app/api/jobs/route.ts: GET ?chatId= polling endpoint
- components/artifacts/job-card.tsx + registry entry: polling activity card
(2s) → syncFromServer on finish; research-brief card (markdown + sources)
- src/agent/prompts/20-jobs.md: research doctrine for the teacher
- tests/jobs.test.ts: store CRUD, spawn hook via scripted mock teacher,
runner completion/failure with fake model + stubbed fetch
Layout:
- Home = knowledge-graph placeholder (main view) with new-session input
docked below; session list moved out of home into a hamburger drawer
- SessionDrawer: slide-over session navigation (backdrop/ESC close, active
highlight, fetches /api/chats on open) on both home and chat headers
- Chat header loses the back button — the drawer is the navigation
Math (inline $ was silently not rendering):
- @streamdown/math defaults singleDollarTextMath:false — now
createMathPlugin({ singleDollarTextMath: true }) in message + reasoning
- katex.min.css imported in layout (streamdown does not inject plugin
styles; display math only looked right via browser MathML fallback)
- QuizCard/AnsweredCard route question/options/explanation through
MessageResponse; user chat bubbles render markdown+math too
- Currency hazard: micromark-extension-math@3.1 lacks pandoc's
closing-digit rule, so bare '$5 and $10' parses as math — defense is at
the source: system prompt now instructs escaped \$5 / 'USD' for money
Hydration fix (React #418):
- QuizCard shuffled options with Math.random() — server/client orders
diverged. shuffleOptions now takes an injectable RNG; QuizCard passes
seededRandom(toolCallId) (mulberry32/FNV-1a in question-core). Same
question → same stable order across reloads; still varies per question.
Tests: 53 pass (5 new math-rendering pins incl. fenced-vs-one-line $$
behavior and the escaped-currency contract). tsc + next build clean.
Verified live in browser: inline/display math in text + cards, drawer
open/navigate/active-highlight/ESC, no console errors, no font 404s.
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