[richshaw]

Fixes #569.

Overlaps #573, which also edits src/app/api/signups/magic-compose/route.ts (questions from Magic Compose). This PR changes two lines there. Whichever lands second gets a small merge.

The problem

Magic Compose's draft schema caps the title at 120 characters and the description at 2,000. If the model went over either one, the route threw the whole draft away, and the organizer saw "AI draft did not match expected shape — try again or adjust your prompt." When an organizer asks for a long announcement to be kept word for word, the model goes over the same way on every retry, so trying again never helps.

The fix

• New src/lib/magic-compose/fit-text.ts:
  • shortenToLimit(text, max) cuts at the last space before the limit and ends with "…", staying within the limit. It drops any punctuation left at the cut, never splits an emoji, and cuts mid-word only when there's no space in the second half.
  • fitDraftText(raw) applies that to title and description on the model's raw output and returns one warning per cut. The limits are imported from src/schemas/signups.ts, not typed in.
• The route (src/app/api/signups/magic-compose/route.ts) runs fitDraftText before MagicComposeDraftSchema.safeParse. The cut warnings come first in the response's warnings, so the build page's banner shows them, for example: "The AI's description was longer than 2,000 characters, so the end was cut off. Check it below." The title and description can be edited right below that banner.
• FullDraftSchema is unchanged, so the MCP create_signup tool still refuses an over-long value with invalid_input.
• The prompt and its golden file are unchanged. Other shape failures (too many slots or fields, a missing title) still get the generic message.
• CHANGELOG entry under Fixed.

Tests

• fit-text.test.ts covers:
  • cutting at a space, trimming punctuation, cutting mid-word when there's no space, and not splitting an emoji
  • a long description and a long title, each cut to its limit with a warning
  • the rest of the draft kept as it was
  • no warning for a draft within the limits
  • non-draft input passed through untouched
• route.db.test.ts has new tests that drive POST with the real parse, persistDraft and Postgres, with only the session and the model stubbed:
  • a description of about 2,100 characters makes the signup with all 3 slots, a saved description of at most 2,000 characters ending in "…", and the warning
  • a title over 120 characters gets the same treatment
  • a draft within the limits gets no warning
  • Without the route change, the first two tests fail.
• signups-write.test.ts: create_signup refuses a description of 2,001 characters with invalid_input and creates nothing.
• Ran and passed: pnpm lint && pnpm typecheck && pnpm knip && pnpm test (1390 tests) and pnpm test:db (539 tests). No page or client code changed, so I didn't run pnpm build.

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[richshaw]

Tophat: passed

I ran 5675f19 locally with pnpm dev and Postgres 16, in Chromium at 1280×900 and 390×844. Magic Compose was pointed at a local stub model through LLM_BASE_URL. The stub returns a fixed 3-slot draft, with a description of about 2,200 characters, a title of about 140 characters, or no slots, depending on a keyword in the prompt.

Check	Result	What I saw
Before, on base 6d30a99: a draft with a long description	✅ (bug reproduced)	Stayed on /app/signups/new with "AI draft did not match expected shape — try again or adjust your prompt". No signup was made.
After: the same draft, desktop	✅	The draft opened on the Build tab. "A few things to double-check" read "The AI's description was longer than 2,000 characters, so the end was cut off. Check it below." The saved description is 1,997 characters and ends "…with nuts…", with the full stop before the cut dropped. All 3 slots were kept.
After: long title and long description, phone	✅	Both warnings were listed, title first. The saved title is exactly 120 characters, cut at a space and ending in "…". The layout fit at 390px with no sideways scroll.
After: a draft within the limits, phone	✅	Only the "Here's your draft" banner appeared, with no double-check box. The description was saved unchanged.
A draft that's wrong in another way (no slots)	✅	It still shows the generic "did not match expected shape" message. The POST returns 500, the same schema_mismatch → internal mapping as on main, and that 500 is the only console error.
Cut signup published and opened as a visitor	✅	Publish worked. /s/[slug] shows the shortened title and description, and Sign up is offered on all 3 slots.
MCP create_signup still refuses a 2,001-character description	✅	src/mcp/tools/signups-write.test.ts and fit-text.test.ts: 36 passed. route.db.test.ts: 6 passed.

For the owner (UX): when the AI writes a title over 120 characters or a description over 2,000, the organizer now gets the draft with the text shortened at a word boundary and ending in "…". The yellow "A few things to double-check" box says what was cut. Before this change they got an error, and retrying failed the same way every time. Screenshot 579-before-longdesc-desktop shows the old behaviour, and 579-after-longdesc-desktop and 579-after-longtitle-phone show the new one. Nothing changes for a draft within the limits (579-after-normal-phone).

Screenshots are in https://claude.ai/code/session_016aQEgj8JvbpAMX1SBKqLMA.

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[richshaw]

Review: passed (round 1)

Magic Compose used to throw away a whole draft when the model wrote a title over 120 characters or a description over 2,000. Now the route shortens those two fields before MagicComposeDraftSchema.safeParse, and it puts one warning per cut at the top of the response's warnings. shortenToLimit stays within the limit: it keeps max − 1 characters plus "…", never splits a surrogate pair, cuts at a space only when that space is in the second half (so a title can't fall below TITLE_MIN_LENGTH), and falls back to the untrimmed head if trimming punctuation would leave nothing. The limits come from src/schemas/signups.ts, the same constants FullDraftSchema uses, so the cut and the check can't disagree. FullDraftSchema is unchanged, so MCP create_signup still refuses an over-long value with invalid_input, and signups-write.test.ts pins that. Every "Done when" item in #569 is met: the route DB tests cover a long description, a long title and no warning within limits, and the CHANGELOG has an entry under Fixed.

Blocking (0): none
Optional (2):

• src/app/api/signups/magic-compose/route.ts:118: when the draft fails Zod for some other reason, the log still records raw.value, not fitted.value. That's arguably the right choice for operators. No change needed.
• #573 also edits this route, as the description says. Whichever lands second gets a small merge.

Earlier threads: none. Copilot couldn't review because the quota was used up.
Checks: CI is green on 5675f19 (lint-type-test, e2e, CodeQL). The tophat passed on this exact SHA, and no runtime code has changed since.

Gate: owner (UX). Organizers now get a shortened title or description and a yellow "A few things to double-check" warning, where before they got an error. Worth a look: the tophat's screenshots 579-after-longdesc-desktop and 579-after-longtitle-phone, and the warning wording "The AI's description was longer than 2,000 characters, so the end was cut off. Check it below."

https://claude.ai/code/session_0156kgzuGdEEEHhyCuFXvuYv

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