Seam (spec lane, ruled): `gen:react-blocks` stops emitting `skills/objectstack-ui/contracts/react-blocks.contract.json` — the markdown rendering becomes the single AI-facing output (#14296 item 3 = A)

[os-litant]

Seam card filed by the skills lane seat (session session_01LraLgQVGq8egUwfYZpbYt1) under the maintainer's ruling on #14296 item 3 = A (comment 5507419465, 2026-09-02 09:27Z, director seat relaying 「其他同意」). Program #14292. Filed unassigned for the spec lane; ⛔ the objectstack-ui skill flights do not touch generated output.

The ruling, verbatim in substance

scripts/build-react-blocks-contract.ts (packages/spec, run as gen:react-blocks / checked as check:react-blocks) writes the same content twice — skills/objectstack-ui/contracts/react-blocks.contract.json (5,352 tokens) and skills/objectstack-ui/references/react-blocks.md (3,153 tokens): same four blocks, same prop counts, byte-identical note strings. The JSON rendering has zero in-repo consumers (one comment mention only), and objectui origin/main has zero consumers (git grep react-blocks.contract.json is empty there — re-measured 11:5xZ). The generator stops emitting the JSON; the file is deleted; the markdown is the single AI-facing output. Customers stop paying 2.8% of the published bundle for a second rendering of one table.

Everything that moves with it (the cost the ruling carries into this card)

1. Generator — packages/spec/scripts/build-react-blocks-contract.ts: drop the JSON writer; --check compares the markdown only. package.json:292-294 scripts keep their names.
2. Sync gate — check:react-blocks (runs in lint.yml, per .gitattributes:133) now verifies one artifact.
3. .gitattributes — drop the merge=os-regen row at :155 (react-blocks.contract.json); keep :156 (the markdown). Update the comment at :121 ("both halves of the react-blocks contract").
4. AGENTS.md:746 — the generated-artifacts row | The react-blocks contract | check:react-blocks | gen:react-blocks | stays but its artifact list names only the markdown. Governed surface ⇒ that edit lands draft-only through the human-merge path (request review from os-zhuang and hotlong, no ready flip, no enqueue).
5. Ratchet self-test — scripts/check-skills-token-ratchet.mjs uses the JSON as a boundary fixture (genContract at :687, "a real path on this tree") and lists it in the generator-owned exclusion set (:803); both must move to another real generator-owned path (e.g. references/react-blocks.md) or the self-test reds on a missing file. Run the self-test.
6. ADR-0082 (docs/adr/0082-react-component-contract-governance.md) — the sentence at :39 naming both renderings and the chain diagram at :87 are corrected to one rendering. docs/adr/** is governed ⇒ draft-only, same review path.
7. check:skill-refs / check:skill-docs — verify neither enumerates the JSON; check:skill-identifier-liveness Leg 1 reads published files, so the deletion shrinks its population.

Landing rules

• One PR, Fixes #<this card>, governed (AGENTS.md, docs/adr/**, skills/**) ⇒ stays DRAFT; review requested from os-zhuang + hotlong with draft: true; a human merge is the review record.
• No changeset is owed unless packages/spec publishes something that changes (scripts/ in a published package — verify with scripts/check-empty-changeset.mjs's enumeration; skip-changeset if it releases nothing).
• Reverse verification: run check:react-blocks at the current head (green, two artifacts), delete the JSON without changing the generator (the gate must go RED — the deletion is real), then land the generator change (green, one artifact).
• The ratchet's generator-owned population shrinks by one file — no ceiling row exists for it, so the ratchet script changes only in the self-test fixtures named above.

Not in scope

Option C of the same item (moving evals/ out of the published tree) is a later question recorded on #14292, not ruled. The objectstack-ui split (#14298 round 2) proceeds independently and does not touch contracts/ or references/.

Dedupe: a targeted search_issues for this seam returned zero; a control query on the same engine returned 16 hits (so the zero is a reading, not a silent-zero). Nearest neighbours, none this: #14298 (the ui flight that deferred it), #13772 (the closed ui sweep that first measured the double rendering).

Refs: #14296 (ruling) · #14292 (program anchor) · ADR-0082.