assemblePrompt used template.replace("{{GATE}}", ...), and String.replace
with a string argument substitutes only the FIRST occurrence. All three
placeholders appear twice in tutor-system.md, because the document names
them in its own header paragraph before using them:
Assembled per turn. `{{GATE}}` is `renderGate()` from `lib/gate.js`;
`{{VARIETY}}` and `{{FOCUS}}` are one-liners built from recent state.
So the rendered gate replaced the backticked mention mid-sentence, and the
real slot further down was sent to the model as the literal text "{{GATE}}".
The mechanism that decides what the tutor is allowed to teach was delivered
in the wrong place, with a template token standing where it belonged, and
the same for VARIETY and FOCUS. Confirmed by capturing what the app
actually put on the wire: three unfilled placeholders at lines 60, 86 and
141.
Substitution is now anchored to a whole line, which is what distinguishes a
slot from a mention -- the header's are inline and backticked. The
replacement is a function because renderGate() output contains "$"
sequences that String.replace would otherwise interpret.
The existing tests could not have caught this. They ran against a synthetic
template naming each placeholder exactly once, which is precisely the
property the shipped file lacks. The new ones run against
prompt/tutor-system.md itself: no slot may survive unfilled, the header
must come through intact, and the gate must land between the profile and
the pre-flight check. Both fail against the old code.
Also appends a HOUSE STYLE section after the shipped prompt -- an addition
by the app, not an edit to the file, which still ships byte-identical.
It covers two things the prompt leaves to inference. The language of
explanation is never actually stated: "한글 and English only" is a rule
about retiring romanization, and everything else only implies English. A
strong model infers it; gpt-oss-20b delivered a full grammar lesson in
Korean to a student on unit 1.1 who cannot yet read it. And no-markdown is
stated outright at line 96 and was ignored anyway, so it is restated where
the consequence is visible: the app renders **bold** and nothing else, so a
table arrives as rows of literal pipes.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
React + Vite + TypeScript, PWA, offline-first. Six tabs: 수업 오늘 단어 문장
문법 한글, plus the full-screen SRS review overlay, the reading drill, the
conjugation trainer and the 두벌식 keyboard.
The visual language is carried over deliberately: two hand-tuned palettes,
three type stacks, about a dozen component classes, zero border-radius and
no icons anywhere — Korean glyphs do the work icons would.
THE GATE is the reason this app exists. buildGate() already took a
vocabQuery hook; filling it with a band query is what turns 371 hand-typed
words into something that scales. Three refinements sit inside that hook,
all of them narrowing:
1. words a not-yet-finished unit is the first to introduce are excluded,
so a frequency ceiling cannot smuggle 3.4's material into 2.1;
2. Phase 1 is filtered by the phonological ladder;
3. the list is capped at 800 by frequency, because renderGate() inlines
it into the prompt — strictly more restrictive than the band, so it
cannot leak.
prompt/tutor-system.md ships unchanged with {{GATE}} filled by renderGate().
Confidence is clamped per turn. The artifact wrote the model's ::progress
number straight into the sole gate on advancement, so one hallucinated 95
skipped a unit.
stub-tutor.ts stands in for the model on the artifact's exact contract —
onText receives cumulative text, an aborted turn keeps what it streamed —
so the real endpoint drops in without touching the UI. It rotates all four
task types and climbs progress gradually, which makes every render path
reachable with no server.
Two artifact bugs are not ported: task state lived in the full-page
re-render, so anything arriving mid-answer wiped typed text and placed
chips; and the day number was computed once at module load, so a session
left open overnight scheduled against yesterday.
Verified in a browser: all six tabs work, and after a hard reload with the
network cut every tab still works — including dictionary search out of OPFS.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
