Conciseness

The body is efficient and dense with earning tokens — activation criteria, artifact selection, workflow steps, anti-patterns, and a checklist, with no padding explaining concepts Claude already knows. It is not a 5 because passages like the tool-safety paragraph ('Run pinned generators with least privilege: no network or secret access by default...') and some anti-pattern prose could be tightened slightly without losing clarity.

Actionability

Fully executable, copy-paste-ready guidance covering the common cases: a complete OpenAPI 3.1 schema example, a `satisfies`-typed mock, a provider mapping function, `npm run generate:api-types`, and concrete FAIL anti-patterns ('return databaseRow as unknown as OrderSummary'). Even the repo-specific generator command is anchored by an explicit instruction to back it with the repository's pinned generator.

Workflow Clarity

The six-step Consumer-First Workflow and seven-step Contract Change Protocol are clearly sequenced with explicit validation checkpoints: 'generate consumer types successfully / validate consumer fixtures against the contract / validate provider responses / run at least one end-to-end happy path', a 'Merge only when all affected sides agree' gate, and a Completion Checklist. This exceeds the level-4 anchor, which allows only 'most' checkpoints.

Progressive Disclosure

No bundle files exist (references/, scripts/, assets/ are absent), and the single-file body is well organized with clear sections and no buried or nested references. It is a 4 rather than 5 because at ~280 lines some material (e.g., the extended code examples and anti-pattern catalog) could arguably live in one-level-deep reference files, a minor organization gap rather than the ideal split of the top anchor.

Specificity

The description lists several concrete actions — 'Coordinate frontend/backend or service-to-service work through one authoritative machine-checkable contract (OpenAPI, AsyncAPI, Protocol Buffers, or JSON Schema), with generated consumer types and contract-verified integration' — naming the artifact formats and three specific mechanisms. It is not a 5 because 'coordinate work' is more abstract than the fully concrete action verbs in the top anchor, leaving minor gaps in coverage.

Completeness

Both what and when are answered explicitly and concretely: the 'what' is the contract-coordination workflow with generated types and contract-verified integration, and the 'when' is spelled out in the trigger clause 'Use when parallel consumer and provider work must evolve an API or event schema without field drift, mock/production shape mismatch, or one side silently redefining the interface.'

Trigger Term Quality

Good keyword coverage of natural terms users would say: 'frontend/backend', 'parallel', 'API or event schema', 'field drift', 'mock/production shape mismatch', plus format names (OpenAPI, Protocol Buffers). A few natural synonyms are missing (e.g., 'breaking change', 'interface', 'schema-first'), so it does not reach the comprehensive-synonym coverage of the top anchor.

Distinctiveness Conflict Risk

The trigger scenario (parallel consumer/provider work, field drift, mock/production mismatch) carves a clear niche unlikely to fire for the wrong skill. It is a 4 rather than 5 because adjacent skills like API design or general schema work overlap slightly — a user asking for generic API design could plausibly match this description.