Conciseness

The body is pure imperative instruction with zero padding: no explanation of what Spring Boot, JPA, or ArchUnit is, and its one explainer section is explicitly reserved for non-obvious knowledge ('Boot 4 findings the model often misses'). Not score 4 because there is no trimmable over-explanation — even justifications are single clauses ('A review catches a boundary leak once. A failing build catches it every time.').

Actionability

Guidance is executable throughout: a named script with argument ('Run ../springboot-migration/scripts/scan_migration_issues.py <project> and cite its CRITICAL lines'), named verification tools (Taikai, ArchUnit, ApplicationModules.verify()), a restore command ('git checkout -- <file>'), decision rules for comments with delete/shorten lists, and a copy-paste report format template. Not score 4 because concrete commands, named tools, and a full output template cover the common cases with no pseudocode.

Workflow Clarity

The process is explicitly sequenced (Before Step 1 → Step 1 reference-loading matrix → Step 2 passes A–F in order → severity-ordered report) with validation checkpoints: 'Run the suite first, so you know what is red before you change anything', 'Prove each finding by running it. Restore every file you break', and a fallback when the migration script is absent. Not score 4 because the risky operations (running/breaking code) have an explicit run-then-restore feedback loop, and the report ends by naming what the review could not see.

Progressive Disclosure

SKILL.md is a well-organized dispatcher: the Step 1 focus→reference table signals all ten top-level references, and every referenced path exists in the bundle. Not score 5 because the testing material sits two levels deep — references/testing/traps.md and testing/boot4-test-toolkit.md are reachable only through references/test-review.md and are not surfaced at the top level, a minor deviation from the one-level-deep ideal; not score 3 because the table itself is clear, all references are real files, and the intermediate file carries substantive content rather than acting as a bare pointer.

Specificity

The description lists multiple concrete actions — 'review, check or diagnose… a pull request, diff, module or file before it merges; a slow endpoint or query (N+1, unbounded reads, JPA and Hibernate performance); security, JSpecify null-safety, architecture boundaries or Boot 4 migration risks' — with comprehensive coverage of the skill's review passes. Not score 4 because there is no meaningful coverage gap; the actions are specific and enumerated rather than merely 'several'.

Completeness

It opens with an explicit 'Use when asked to review, check or diagnose Spring Boot code' clause and enumerates concrete trigger scenarios (pre-merge review, slow endpoint, security/null-safety/architecture/migration risks, test effectiveness), so both 'what' and 'when' are answered explicitly. Not score 4 because the 'when' is not merely present — it lists specific trigger situations rather than needing more specificity.

Trigger Term Quality

Natural phrasings a user would actually say are comprehensively covered with synonyms: 'review', 'check', 'diagnose', 'pull request', 'diff', 'slow endpoint or query', 'N+1', 'security', 'null-safety', 'migration risks', 'tests would catch real bugs'. Not score 4 because both common verbs and their variations are present, and it adds explicit negative triggers ('Not for Kotlin-only code, non-Spring frameworks, or generic review advice without code context').

Distinctiveness Conflict Risk

It carves a clear niche (Spring Boot code review with proof-by-running) and explicitly excludes adjacent territories: 'Not for Kotlin-only code, non-Spring frameworks, or generic review advice without code context.' Not score 4 because the overlap risk with a generic code-review or migration skill is pre-empted by these exclusions and by scoping migration to 'risks in existing code' rather than migration planning.