Conciseness

The body is mostly dense, code-first content, but it duplicates whole sections — "When to Activate" and "When to Use This Skill" repeat nearly the same bullet list, and the expand-contract pattern is fully explained twice ("Renaming a Column (Zero-Downtime)" and "Zero-Downtime Migration Strategy"). This is more than minor trimming, matching anchor 3 ('could be tightened') rather than 4.

Actionability

Fully executable, copy-paste-ready guidance throughout: exact SQL for every pattern (including a batching loop with FOR UPDATE SKIP LOCKED and GET DIAGNOSTICS), per-tool CLI commands ("npx prisma migrate dev --create-only", "migrate -path migrations -database \"$DATABASE_URL\" up"), and complete Django migration classes. This matches the anchor-5 example of executable code covering common cases.

Workflow Clarity

The expand-contract strategy has a clear phased sequence with a day-by-day timeline, and the Migration Safety Checklist plus "Verify data consistency" in Phase 2 act as checkpoints. It is capped below 5 for destructive/batch database operations because there are no explicit fail-and-retry validation loops — only a passing "force VERSION (fix dirty state)" hint — whereas anchor 5 requires explicit validate/fix/revalidate steps.

Progressive Disclosure

No bundle files exist and the single-file body is well-sectioned (per-DB patterns, per-ORM workflows, strategy, anti-pattern table), with each subsection compact enough to justify inlining. It is a 4 rather than 5 because at ~340 lines the four ORM-specific workflow sections could be split into one-level-deep reference files, and the two 'when to use' sections fragment navigation.

Specificity

Phrases like "schema changes, data migrations, rollbacks, and zero-downtime deployments across PostgreSQL, MySQL, and common ORMs (Prisma, Drizzle, Django, TypeORM, golang-migrate)" list several concrete capability areas plus specific tools. It sits at anchor 4 rather than 5 because capabilities are stated as noun topics ("best practices for X") rather than multiple concrete verb-led actions, leaving minor gaps in coverage.

Completeness

Both what ("Database migration best practices for schema changes, data migrations, rollbacks, and zero-downtime deployments...") and when ("Use when planning or implementing database schema changes") are explicitly present. It falls short of anchor 5 because the trigger clause is narrow — it omits troubleshooting, reviewing migration PRs, and setting up migration tooling, which the body itself lists as use cases.

Trigger Term Quality

Natural terms users would say — "database migration", "schema changes", "rollbacks", "zero-downtime", plus five tool names — give good keyword coverage. Not a 5 because common variations users actually say ("add a column", "ALTER TABLE", "migrations", "backfill") are missing.

Distinctiveness Conflict Risk

A clear niche with distinct triggers: database migrations with named engines and ORMs ("PostgreSQL, MySQL... Prisma, Drizzle, Django, TypeORM, golang-migrate") is unmistakable and would not plausibly fire a general SQL, ORM, or devops skill. Matches the anchor-5 example's structure of distinct, specific triggers.