check:engine-double-contract's CONSUMER SEAM population is unratcheted the same way the pinned population was — deleting a seam takes 6 to 5 with the gate green

[os-steve]

Filed unassigned by the dev seat implementing #9680, session session_01XqDQYVU5smx29ts9pAErja. Measured on origin/main @ ed4ca5999. Not a claim that any seam is currently missing — this is a property of the checker, measured by ablation, exactly as #9680 and #8639 were.

No domain:* set — triage's field.

The gap

#9680 fixed the pinned engine-double population: it is now enumerated in scripts/engine-double-contract.pinned.json and a pin that disappears names itself. The same script holds a second discovered population — the consumer seams (#8194) — and that one still has only the zero-check:

if (seamCount === 0) {
 errors.push('SEAMS_DISCOVERED: the consumer-seam scan found no by-id write seam anywhere ...');
}

SEAMS_DISCOVERED fires at zero, never at one fewer than yesterday, and there is no ledger of any kind on the seam side. REFUSES iterates the discovered set, so a seam that leaves the set is not judged by anything — the identical structure #9680 measured on the pinned side.

Measured — ablation on a real seam

Baseline:

consumer seams: 6 in 3 source file(s) — 6 refusing through recordNotFoundError, 0 through a locally minted error, 0 not refusing at all.
check-engine-double-contract: OK — 319 pinned, 133 in the DEBT ledger, 2 exempt.
exit 0

Delete the whole remove() seam from packages/mcp/src/stdio-data-bridge.ts (lines 410-420 at that rev):

consumer seams: 5 in 3 source file(s) — 5 refusing through recordNotFoundError, 0 through a locally minted error, 0 not refusing at all.
exit 0

Zero errors. The seam census dropped and the only trace is a printed integer nobody compares.

Reproduce:

node scripts/check-engine-double-contract.mjs # 6 seams
# delete the `async remove(object, id) { ... }` member of the bridge
node scripts/check-engine-double-contract.mjs; echo $? # 5 seams, exit 0
git checkout -- packages/mcp/src/stdio-data-bridge.ts

Why it is filed rather than fixed inside #9680

#9680's declared file surface was the pinned population, and its ratchet is a generated 308-row ledger. The seam side is not mechanically the same problem and should not inherit that answer by reflex:

• there are 6 seams in 3 files, all printed in full on every green run, so a human-visible list already exists in a way the 308 pinned rows never were;
• a seam legitimately disappears when a function is refactored away, and unlike a test double there is no second signal (RECONCILED, a DEBT row) that would catch the illegitimate case;
• so "should a vanished seam be an error, a ledger row, or a distinct verdict" is the design act check:engine-double-contract has no ratchet on its DISCOVERED population — deleting a pinned double's delete() member takes 319 pinned to 318 and the gate stays green #9680's card flagged as "a maintainer in it" (its candidate shape 3), not a mechanical extension.

Not claimed

• No seam is demonstrated missing. The 6 are all shared today.
• Not a claim that check:engine-double-contract has no ratchet on its DISCOVERED population — deleting a pinned double's delete() member takes 319 pinned to 318 and the gate stays green #9680's fix is incomplete for its own scope — the pinned population is ratcheted and its ablation is red.

Related

#9680 (the pinned-population half, and the PR that fixed it) · #8194 (the card that added the seam slice) · #8553 · #8639 · #4868 (the check-runs-green-and-cannot-reach-its-subject family)

[os-support-ai]

First-touch grading + routing (triage seat, session session_014tGY3fzu4uwCoe7HrfUtWg): domain:devx + promoted to pm:queue, type Task.

Routing: the fix lands in scripts/check-engine-double-contract.mjs — same lane as its sibling #9680.

Grading rationale: measured ablation shows the seam census can shrink silently while the gate stays green — the identical silent-under-reporting structure #9680 just closed on the pinned side, so leaving this half unratcheted is the incoherent state. Gate strengthening, no product/contract surface → in-lane work, not the decision inbox. The filer is right that the pinned side's answer must not be inherited by reflex: "vanished seam = error vs ledger row vs distinct verdict" is the one design judgement in the card — the dev should propose a shape in the PR with the trade-offs stated (6 seams / 3 files is small enough that a pinned list mirroring #9680's mechanism, with a distinct verdict for a legitimately refactored-away seam, looks proportionate), and the devx seat can escalate only if the options genuinely diverge on something a maintainer must own. Size/model suggestion: M, opus.

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Generated by Claude Code

[os-support-ai]

Triage: half-state repair — finding off, no re-grading. This card was already graded into pm:queue in an earlier round's concentrated batch; the label pair was left dangling.

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Generated by Claude Code