Conciseness

The body is free of padding and never explains concepts Claude already knows — every sentence is a compressed directive — but the prose is uniformly dense and abstract (e.g., 'A failed parameter family is not a reason to try indefinitely') and several passages, particularly the §1 binding caveats, could be tightened, matching anchor 3's 'mostly efficient but could be tightened' rather than anchor 4.

Actionability

Concrete guidance is present and specific for an instruction-only skill: the §3 decision table enumerates required answers (Evidence, Disposition, Next evidence), §1 names exact binding inputs (repository/ref, pinned immutable ref), and §5 names distinct verification layers with a read-back-at-consumption-point checkpoint. Minor gaps — no worked example or concrete probe per stage — hold it at anchor 4 rather than 5.

Workflow Clarity

Five numbered stages form a clear sequence with explicit validation checkpoints and feedback loops: 'When evidence fails, inspect raw signals, seek a falsifier and correct the root cause or the mistaken criterion. Retry only after a relevant input or hypothesis changes', plus calibration of new guards on healthy and failing inputs. This sits between anchors 4 and 5; verification steps are named abstractly rather than as concrete executable checks, so 4 is the better fit.

Progressive Disclosure

The body is an overview that appropriately splits detail into references/ with well-signaled, one-level-deep links ('Read [evidence and fit](references/evidence-and-fit.md) before selecting changes'), and all three referenced paths resolve to real files. Minor gaps: feature-investigation.md is never referenced from the body (only reachable via skill-composition.md), and the reference files cross-link each other, matching anchor 4 rather than 5.

Specificity

The description names the domain ('Improves an existing application using its code, product contract, authorized work history and competitor evidence') and several actions ('Carries authorized changes through implementation and user-result verification'), but the actions are process-level abstractions rather than concrete capabilities, matching anchor 3 more than anchor 4's 'several specific actions' like 'fills forms, converts pages to images'.

Completeness

Both 'what' (improves an app using code, contract, history and competitor evidence) and 'when' (explicit 'Use for' clause with concrete trigger phrases) are present, matching anchor 4. It falls short of anchor 5 because the trigger set is narrow and idiomatic and the 'what' is dense with unexplained jargon like 'REA'.

Trigger Term Quality

'Use for 取长补短、取其精华去其糟粕、参考竞品优化应用 or evolving an app from successful and failed work' provides natural bilingual trigger phrases users would actually say, but common English variants like 'optimize app' or 'learn from competitors' are missing, so it falls just short of anchor 5's comprehensive synonym coverage.

Distinctiveness Conflict Risk

The niche (evolving an existing app from prior work and competitor evidence) is distinct, and 'use skill-evolver for Skills' explicitly disambiguates the closest sibling skill, matching anchor 4's 'mostly distinct; minor overlap risk' with generic code-improvement skills.