Sandcastle re-invokes agents up to maxIterations even when the work is
already done — the decomposer was looping 4x re-writing the same epic
on every dispatch. Two halves to the fix:
- Pass completionSignal: "<promise>COMPLETE</promise>" explicitly on
all three run() calls (decompose, implementer, reviewer). Makes the
contract visible alongside maxIterations instead of relying on
sandcastle's default.
- Append a "Signal completion (required)" section to each prompt
telling the agent to emit the literal marker as its final line when
the work is genuinely done, plus a "do NOT emit if..." list to
discourage premature signaling.
Closes the staleness gap after the 10-commit coverage epic shipped.
Doc sync (item 1 from the user's choice):
- CLAUDE.md Quick Start: adds pnpm coverage:aggregate / coverage:diff
/ mutate to the command listing
- CLAUDE.md: new "Sibling architecture: coverage (ADR-020)" section
after the conformance gate table — captures the 4-layer table +
points at docs/guides/coverage.md + ADR-020 + says agents must run
coverage:diff before reporting complete
- AGENTS.md preamble: now lists coverage as a parallel multi-latency
quality system alongside conformance, with the same gate / latency
framing
- PRD frontmatter: status draft -> shipped + shipped date +
shipping-commits list (all 10 SHAs anchoring the trace)
- PRD findings table: each row gets a Resolution column citing the
commit that closed it; conclusion text updated to past tense
- ADR-020 implementation phasing: rewritten as a status table with
each step linked to the commit that shipped it + Boot-time
assertFeatureConformance explicitly marked Deferred with rationale
- docs/guides/coverage.md: removed "Boot wiring lands in the next
story" line; replaced with the deferral rationale + clarified
that two readers (vitest, coverage:diff) consume the manifest
Sandcastle prompts (item 2 from the user's choice):
- .sandcastle/implementer.prompt.md: new "Coverage gates" section
after the conformance-gates list, requiring `pnpm test --coverage`,
`pnpm coverage:aggregate`, and `pnpm coverage:diff` to all pass
before reporting `complete`. Machine-readable JSON shape of
coverage:diff documented (status / uncovered[] / kind enum), with
explicit instructions on how to interpret each kind. Allowlist
expansion requires justification + test.
- .sandcastle/reviewer.prompt.md: AC coverage relabeled to "AC
coverage (acceptance criteria, not test coverage)" to disambiguate;
new check #7 "Coverage gates (ADR-020)" requiring CI's
Coverage — diff (L1) step green + per-layer thresholds met +
no silent allowlist expansion + manifest band drift detection.
Effect: future agent runs through sandcastle now treat coverage as a
first-class blocking gate, parallel to conformance. PRs no longer
discover coverage failures only via CI; the implementer is required
to check before reporting done, and the reviewer is required to
verify.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
