Conciseness

The core TDD message is repeated across 'Following strict TDD prevents these anti-patterns', the 'TDD Prevents These Anti-Patterns' section, and 'The Bottom Line', and the 'Quick Reference', 'Red Flags', and 'Bottom Line' sections overlap substantially. It matches anchor 3 (mostly efficient but could be tightened) rather than anchor 2, since the example pairs and gate functions genuinely earn their tokens.

Actionability

Each anti-pattern has concrete bad/good TypeScript example pairs plus an explicit gate-function decision procedure ('BEFORE mocking any method... IF depends on side effects: Mock at lower level'). This fits anchor 4 (mostly executable guidance with minor gaps) rather than anchor 5, because the code fragments are illustrative (referencing Page, addServer, config) rather than copy-paste runnable.

Workflow Clarity

The gate functions are explicit validation checkpoints with STOP conditions, the Anti-Pattern 3 gate includes a feedback loop ('Run test with real implementation FIRST... THEN add minimal mocking'), and 'Red Flags' serves as a checklist. This matches anchor 5 (clear sequence, explicit validation, feedback loops, checklists) rather than anchor 4, which requires missing checkpoints.

Progressive Disclosure

The single-file skill has no bundle directories (references/, scripts/, assets/ are absent) and no referenced paths to verify, so nothing is buried or nested. It is well-sectioned with headers and a quick-reference table, fitting anchor 4 (good structure, minor organization gaps) rather than anchor 5, since a ~320-line document covering six anti-patterns could plausibly split some detail into reference files.

Specificity

The description names the testing domain and lists three concrete behaviors it prevents ('prevents testing mock behavior, production pollution with test-only methods, and mocking without understanding dependencies'), matching anchor 4's 'several specific actions; minor gaps'. It stays below anchor 5 because capabilities are expressed as prevented anti-patterns rather than a comprehensive list of concrete actions.

Completeness

It explicitly answers 'when' with a concrete 'Use when writing or changing tests, adding mocks, or tempted to add test-only methods' clause, and 'what' with three explicitly named prevented behaviors. Both are present with concrete trigger phrases, matching anchor 5 rather than anchor 4 where the 'when' would be less specific.

Trigger Term Quality

'writing or changing tests, adding mocks, or tempted to add test-only methods' provides natural phrases a user would say when needing this skill. It misses common synonyms like 'stubbing', 'test doubles', or 'unit tests', so it fits anchor 4 (good coverage, a few natural terms missing) rather than anchor 5.

Distinctiveness Conflict Risk

Mock usage and test-only production methods form a fairly distinct niche with specific triggers, but it could still fire for general TDD or code-review skills. This matches anchor 4 (mostly distinct, minor overlap risk with closely related skills) rather than anchor 5's minimal conflict risk.