Conciseness

Every section carries project-specific information — the blue/green deploy window, lint rule names, and repo-specific commands — with no padding or explanation of concepts Claude already knows. The per-operation playbook is delivered as a dense table rather than prose, so every token earns its place.

Actionability

The body gives copy-paste-ready commands (`cd packages/db && bunx drizzle-kit generate`, `bun run check:migrations`, `bun run db:migrate`, the `grep -rn "contract-pending" ...` check) plus exact SQL patterns (`CREATE INDEX CONCURRENTLY`, `NOT VALID`, batched idempotent backfills) and literal annotation/marker formats. It fully instructs rather than describes.

Workflow Clarity

The workflow is a clear 6-step sequence with explicit validation checkpoints: the lint gate with per-tier error handling, schema-mock regeneration, re-running drizzle-kit generate to detect drift, and local migration verification. Feedback loops (fix, re-run, split the PR) are present for the destructive and batch operations the skill governs, satisfying the destructive-op validation requirement.

Progressive Disclosure

Sections are well-organized and clearly signaled (The window, Expand/contract, playbook, Tracking the contract, Judgment, Workflow, Hard rule) with all referenced paths being real repo files. However, the ~92-line body keeps the full per-operation playbook and annotation catalog inline with no bundle files for splitting, exceeding the under-50-line simple-skill exception.

Specificity

"Author or review a Drizzle DB migration for zero-downtime safety — expand/contract phasing, backward-compatibility with the deployed app version, and writing the `-- migration-safe` acknowledgment" lists multiple concrete actions covering everything the skill does, with no coverage gaps. It is not a 4 because the enumerated actions comprehensively span the skill's responsibilities.

Completeness

It explicitly answers both questions: the "what" (author/review a migration, expand/contract phasing, backward-compatibility, writing the annotation) and the "when" via a literal "Use when adding/editing files under `packages/db/migrations/` or changing `packages/db/schema.ts`" clause with concrete triggers. The when-clause is fully explicit, so the 4-anchor's "could be more specific" does not apply.

Trigger Term Quality

Strong natural keywords — "Drizzle DB migration", "zero-downtime", "schema", "check:migrations", plus concrete file paths (`packages/db/migrations/`, `packages/db/schema.ts`). It falls short of 5 because common synonyms a user might say — "schema change", "database migration", "deploy safely" — are absent, but coverage is well beyond the 3-anchor's "some relevant keywords".

Distinctiveness Conflict Risk

"Drizzle DB migration", the named `check:migrations` lint, and repo-specific path triggers carve out a clear niche with essentially no overlap risk against other skills. Not a 4, because the triggers (specific file paths and a named lint) leave no meaningful overlap with closely related skills.