Architecture record for the agent-first coverage initiative seeded by
the 2026-05-13 PRD. Captures the durable decisions:
- 4-layer architecture (L0 vitest, L1 diff, L2 aggregate, L3 mutation)
- Manifest-driven coverage band as single source of truth (vitest +
assertFeatureConformance + pnpm coverage:diff all read from it)
- Cover-the-diff (changed lines), not cover-the-new-code
- Committed coverage/summary.json (no SaaS), trend via git log
- Mutation testing scoped to entities + use-cases, on-demand only
- Machine-first output format (JSON stdout, human stderr)
Glossary gets a new "Coverage" section with 7 entries (coverage band,
L0-L3 layers, diff coverage, mutation testing, mutation score,
coverage/summary.json), plus two relationship rows and a flagged
ambiguity for "coverage" qualifiers.
prompt-context.sh hook gets a 9th keyword group — when a prompt
mentions coverage / uncovered / lcov / mutation / stryker, the
relevant ADR + guide path are injected as additional context for
the turn.
This is the documentation layer of the coverage epic. Implementation
(manifest schema, vitest auto-derive, scripts, boot assertion,
mutation tooling) lands in subsequent stories.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
docs/glossary.md is the shared vocabulary source for humans and agents.
Resolves every cross-cutting term used in this repo (feature, use case,
manifest, slice, conformance, dispatch, ...) with one-sentence definitions,
relationships, and flagged ambiguities. Linked from CLAUDE.md "Read First"
and AGENTS.md preamble so every session loads it early.
.claude/skills/ installs four mattpocock skills adapted to this monorepo:
- to-prd: writes to docs/work/prds/ with the repo's PRD frontmatter +
merged user-stories/implementation/testing sections
- grill-with-docs: points at docs/decisions/ + docs/glossary.md; adds
feature.manifest.ts + conformance-rule cross-checks
- grill-me: minor — adds pnpm work / fallow / manifest shortcuts
- handoff: adds the repo's specific don't-duplicate artifacts list
Also fixes a missed "Phase-1" residual in CLAUDE.md's Read First section.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
