Conciseness

The body is lean and assumes Claude's competence: 'Non-relational provider with its own parallel query pipeline. Uses JSON for document materialization.' Every bullet conveys project-specific knowledge Claude would not already have (no migrations, ETag concurrency, Linux emulator limitations, exact env var and skip-attribute). Every token earns its place, matching anchor 5.

Actionability

Concrete, mostly copy-paste-ready guidance: '`EnsureCreated()`', the env var '`Test__Cosmos__DefaultConnection`', and the exact 'ConditionalFact(typeof(CosmosTestEnvironment), nameof(CosmosTestEnvironment.IsNotLinuxEmulator))' attribute. Minor gaps remain — e.g. partition key configuration is mentioned as required but no example is given — so anchor 4 rather than 5.

Workflow Clarity

This is a single-purpose reference skill with no multi-step process, and its guidance is unambiguous (use EnsureCreated instead of migrations, ETag for concurrency, skip attribute for unsupported emulator features). It falls just short of a clean 5 because items like 'Partition key configuration required for performance' state a requirement without showing how to satisfy it.

Progressive Disclosure

The skill is under 50 lines with no external bundle files, and the content is appropriately organized into a two-line overview plus clearly headed 'Key Differences' and 'Emulator for Tests' sections. Per the simple-skill guideline this warrants a 5 with no external references needed.

Specificity

The description names the domain ('EF Core Azure Cosmos DB provider') but the only stated action is the generic phrase 'Implementation details', with no concrete capabilities listed. This matches the anchor 'Names the domain but actions are minimal or generic' rather than anchor 3, which requires 1-2 concrete actions.

Completeness

Both parts are present: a what ('Implementation details for the EF Core Azure Cosmos DB provider') and an explicit when ('Use when changing Cosmos-specific code'). It sits at anchor 4 rather than 5 because the 'what' is vague and the trigger is a single narrow phrase; it is above anchor 3 because the 'when' is explicit rather than implied.

Trigger Term Quality

'Use when changing Cosmos-specific code' supplies a natural trigger term ('Cosmos'), but common variations users might say — 'Cosmos DB', 'NoSQL', 'document database', 'Cosmos provider' — are absent. Relevant keywords exist but synonyms and variations are missing, matching anchor 3.

Distinctiveness Conflict Risk

'EF Core Azure Cosmos DB provider' carves out a clear niche with distinct, unambiguous triggers; no other plausible skill would fire on this description. Minimal conflict risk, matching anchor 5.