Each turn runs claude -p with stream-json in and out and maps its events onto pi's assistant message stream. A process that stops on tool calls is kept alive and continued when pi sends the results back, instead of replaying the whole transcript. API credentials are removed from the CLI environment so turns always bill to the signed-in subscription.
A localhost-only MCP HTTP server, guarded by a per-turn bearer token, lists pi's tools and holds each call until pi has run it and returned the result.
micromark-extension-math's inline closer is code-span logic — any
size-matched $ run closes, backslash-escaped dollars included — so
"$x = \$5$" closed at the escape, errored in KaTeX, and could cascade
into later text. KaTeX itself renders the escaped dollar fine, and its
own auto-render scanner skips escaped dollars, so the author's intent
is unambiguous.
Fix at the render seam (transformMathDelimiters): inside a balanced
inline span, an escaped dollar becomes the dollar-free
\text{\textdollar} before tokenization, with an escape-aware closer
(odd-backslash dollars never close; even-backslash row-break closers
keep closing). Display spans are untouched (a lone $ can't close $$ —
the escape already survives there), prose escaped dollars, code, and
unbalanced spans pass through, and spans without escaped dollars emit
byte-identical text — corpus-verified over 489 dollar-bearing fields
in 40 real sessions (35 changed, all escaped-dollar spans; the
economics session's dollar-amount math now renders).
The latex-testing session's Test-6 question renders 14 KaTeX spans
with zero errors (was 12 + 2 errors). 1578/1578 tests both configs;
typecheck, lint, build, and Electron-runtime smoke green.
- switch the math authoring/rendering contract from \(...\)/\[...\] to the
standard $...$ inline / $$...$$ display: prompts (20-question-tools,
40-formatting), singleDollarTextMath on the renderer, legacy reader kept,
and escape-debris recovery extended to dollar spans (mirroring micromark
delimiter-run rules)
- exact answer membership now precedes debris cleanup in
coerceCorrectAnswer (calculus incident: an exact sentence-final-period
label was stripped as model debris, then rejected); option keys are
passed at the boundary/grading seams, the dock no longer pre-coerces
- a complete, phase-correct JSON-escaping example rides the probe/quiz
tool descriptions (serialized from one canonical body; quiz leads with
type+nodeId), plus the one-sentence JSON-escaping rule in 40-formatting
- ask option descriptions render markdown/LaTeX in the pending dock;
settled cards keep the details line and option descriptions
retroactively, read from the persisted call arguments (chat passes
part.input to AnsweredCard)
1566/1566 tests on both navigator configs; typecheck, lint, production
build, standalone packaging, and Electron-runtime smoke all green.
Demos execute JS and need a browser; the app's own binary now provides
one: main.cjs boots a hidden window + CDP port under --browser-service
(before the single-instance lock - a helper is deliberately a second
instance of this binary), lifetime tied to the server's stdin (EOF =
quit, no orphans). headless.ts connects over CDP as PRIMARY (owner
ruling 2026-10-10), system Chrome stays the fallback, graceful refusal
when neither. Electron's CDP has no Target.createTarget, so the helper's
pre-created window is THE page, reused and reset per job behind a
serialized queue. PDFs and SVGs never reach a browser anymore (native
since stages 1-2); stale Chrome wording in model-facing tool copy made
engine-neutral. Live-proofed end-to-end from the dev tree (helper seen
by process watch, js-ran 42 probe, no orphan). Gates 1523/1523.
Visual-maker SVGs never execute script, so a browser added nothing but a
process. resvg rasterizes in-process now (white background and fitTo
width mirror the old Chrome-page semantics; svgViewport unchanged,
quirks included for parity). The old Chrome path stays verbatim as the
fallback for exotic-SVG parse failures - it was the only path before,
so nothing regresses.
The resvg binary (4MB per platform, one per build) rides the standalone
via the same tracing pattern. Gates 1519/1519; native path pinned
against real SVGs (intrinsic size, viewBox-only 900 default, opts
override, system-font text).
The browser was never the PDF engine - pdfjs always painted the pages;
Chrome only hosted the canvas tab. Now pdfjs-dist v6's own Node
integration (@napi-rs/canvas, its optionalDependency) hosts in-process:
same paint code, Skia canvas, zero browsers, zero temp files, no base64
hop. The whole pdf-reader runs browser-free - the Chrome gate on
pdf_render is gone.
The Skia binary (27MB per platform, exactly one per build - npm installs
only the building machine's) rides the standalone via the same
outputFileTracingIncludes pattern as pdfjs-dist. Verified: builds green
(1515), native render pinned against the real fixture (canonical
single-IDAT PNGs, dpi/72 arithmetic, page-range skipping), and the
canvas loads + paints from inside .next/standalone.
Stages 2-3 (resvg for SVG, the --browser-service demo helper) follow.
Chat records gain version (CURRENT_CHAT_VERSION), stamped by a single
writeChat choke point in the store; absence reads as v1 — existing files
migrate on their next write, no mass rewrite. The graph family (four JSONL
ledgers, sources.json, render-settings.json) shares one lazy sidecar,
graph/format.json; positions stays unstamped (rebuildable) and jobs stay
unstamped (transient).
Downgrade scenario ruled honest-refusal: records stamped newer than the
running build read as absent (chats, logged) or throw (graph family) — a
read-modify-write store never rewrites what it doesn't understand.
Golden fixtures stay the unstamped legacy shape on purpose (lazy v1 is
current-valid by design); the stamped write path is pinned by
tests/schema-stamps.test.ts. Reads never write — the golden byte-identical
pin holds.
THE START BUG (owner report, reproduced live both kinds): new sessions
(?prompt flow — practice and teach alike) sat dead until a second
message, which then persisted WITHOUT the first. Root cause, proven
both directions: the submit POST rode the view's consumeAbort
controller; React StrictMode's simulated remount fires Diet A's
unmount cleanup (model.stop()) ~8ms in and killed the POST mid-flight;
the page's sentInitial guard had already flipped, so it never retried.
Teach was equally broken — only unnoticed, because every teach chat in
use predates the diet and practice starts are always fresh. Fix: the
submit law — POSTs are not abortable by view teardown (they are ~100ms
acks since Diet B and cannot starve the pool); after the ack, a
consumeAbort identity check guards the stream attach. Pinned with the
stop-mid-submit regression test. Live: StrictMode on, practice draft
POST 200/67ms, stream attached, message persisted, problem posed.
PRACTICE PROMPT (00-base): the opening rule — material arrives two
ways, both first-class (picked propositions primary; free-form —
topics, course material, files/PDFs — fully supported, never refused);
as soon as material exists the reply poses, at most one short line
before the problem call, no warm-up interview. Plus the hard law: no
problem is ever conversation — every problem through the tool (no
thinking field/no reveal/no verdict attaches to prose).
GRAPH-CONTEXT PREAMBLE: custom markers flatten to user-role on the
wire, so the old "Contextualization — the learner picked…" read like a
system broadcast in the learner's voice channel. Now the bracket
convention: "[Session context] — picked from the learner's knowledge
map…".
SIDEBAR: busy rows unify to "Working…" for both kinds (the spinner's
default label included); "Practicing…"/"Teacher is working…" retired.
Gates: 1490/1490, typecheck, lint. doctrine's stale doc pointer fixed.
Plan canvas (owner report: arrows clipped at the viewBox edge in dist —
measured 14px/20px cuts in the owner's real plans): blockLayout now
unions node boxes with every edge path's control-point hull (a bezier
never leaves it; the layout calls edgePathD with the renderer's exact
inputs). Dagre's node extent stays the floor, so ordinary plans render
byte-identical; the viewBox origin shifts only when ink bulges past
zero. Verified on both real chats; pins use the owner's real
linear-algebra tree (golden-real-data).
Keyboard-first (owner's law: Enter always submits, arrows always cycle;
text fields the only exception):
- Enter guard split (enter-submits): a focused BUTTON keeps native
Enter only when keyboard-walked (:focus-visible) or inside an open
overlay (menus/dialogs); pointer-clicked transcript buttons submit,
preventDefault suppressing the re-activation underneath.
- Focus hygiene (focus-hygiene): pointer clicks on transient controls
(agent/user thinking toggles, copy, mermaid expand, plan chip) blur
to body — the state clicking empty space produces.
- Session search owns the walk: Up/Down wrap-cycle the filtered rows,
Enter opens the walked row or the first match (quick-open), then
blurs and keeps the query. The Alt-arrow session cycle is RETIRED.
- Registry: model-menu walk/pick entries removed (obvious in-field
navigation, not settings material); question-dock keys stay
displayOnly per owner ruling.
Gates: 1489/1489, typecheck, lint. Verified live end-to-end.
Root cause (postmortem, verified live): Chromium caps 6 concurrent
HTTP/1.1 connections per origin. Every running turn pinned slots for
its whole life — the POST /api/chat response stream plus a reattach
GET stream per visit that never closed on navigate-away — so two
concurrent thinking sessions starved navigation RSC fetches in the
browser queue (147s measured) until the turns settled. Server was
exonerated (3ms curls during the freeze); main thread idle throughout.
- COMPACTION LAW + WIRE DIET (ui-stream): store the states, not the
chunks — replace-in-place snapshot retention keyed by updateSlots,
~100ms coalesced latest-wins fan-out, slim wire drops pi's duplicate
assistantMessageEvent payload.
- DIET B: POST /api/chat acks and closes ({ok:true}) — the turn wire
is GET /stream for everyone, submitter included; send() reattaches
via refetch-first resumeStream(true).
- DIET A: unmount cleanup calls model.stop() — navigating away aborts
the view connection (turns are server-side background objects).
- Answer-flicker fix: resumeStream's eager tail clear moved off the
refetch path (the refetch swaps base+tail atomically; clean-slate
guard restored on refetch failure) — the optimistic answer card
survives refetch latency (1.7s stalls measured on dev).
- Tests converted to the ack contract (drainTurn/drainRunning helpers,
dietFetch mock) + a pin that the POST body reads while the turn runs.
Gates: 1489/1489, typecheck, lint. Live: dual streaming sessions,
navigations 335-648ms, in-page settings 19ms (was 147s).
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