Conciseness

The body is dense and directive ("Use `timestamptz` for instants; store money as integer minor units plus currency"; "expand -> migrate/backfill -> verify -> switch -> contract") and assumes Claude's competence without teaching basics, but the Base Framework boilerplate, the duplication between "Purpose and activation" and "Routing Boundary", and the lengthy workflow-integration/state.json mechanics are trimmable, matching the 4-anchor's minor over-explanation rather than the 3-anchor's unnecessary explanation.

Actionability

Guidance is concrete and executable for an instruction-only skill: an exact output-contract heading list, a per-table mini-specification template, specific commands like `EXPLAIN (ANALYZE, BUFFERS)`, and named tooling. It falls short of the 5-anchor because the Examples section points to references rather than demonstrating a worked case, and the bundled validate_scenarios.py script is never invoked.

Workflow Clarity

A clearly sequenced 7-step workflow with explicit validation checkpoints ("Validate candidates using representative `EXPLAIN (ANALYZE, BUFFERS)` after data exists", migration "verify" step, "abort criteria, and tested rollback or forward-repair") and a completion checklist, so the destructive/batch cap does not apply. It sits between the 4- and 5-anchors because error recovery is stated as an output requirement rather than an explicit validate-fix-retry step in the workflow, and the shipped validation script is orphaned.

Progressive Disclosure

The four references/*.md files are real, one level deep, and clearly signaled ("Read [architecture-and-modeling.md](references/architecture-and-modeling.md)"), but scored against the actual bundle: roughly ten links to shared/base/*.md policies and shared/workflow-contract.md point to files that do not exist in the bundle, and scripts/validate_scenarios.py is never referenced from the body. These dead links and the orphaned script exceed the 4-anchor's "minor organization gaps".

Specificity

"Design, review, or evolve a database schema and its data-integrity, tenancy, migration, indexing, and operational model" lists multiple concrete actions (design, review, evolve) across five named capability areas, giving comprehensive coverage comparable to the top anchor; it is not the 4-anchor because no capability area of the domain is visibly missing.

Completeness

Both "what" ("Design, review, or evolve a database schema and its data-integrity, tenancy, migration, indexing, and operational model") and "when" ("Use when the primary deliverable is a datastore or schema decision") are explicit, but the when-clause states a condition rather than concrete trigger phrases, fitting the 4-anchor where the when could be more specific rather than the 5-anchor.

Trigger Term Quality

Natural keywords are present ("database schema", "migration", "indexing", "tenancy", "datastore"), but common user phrasings such as "ERD", "SQL", "tables", or "PostgreSQL" are absent, matching the 4-anchor (good coverage, a few natural terms missing) rather than the 5-anchor's synonym-level comprehensiveness.

Distinctiveness Conflict Risk

"Do not use for general system planning, query debugging, or generic dependency/security review" explicitly disambiguates against the nearest competing skills, giving a clear niche with minimal conflict risk, which matches the 5-anchor; the 4-anchor's "minor overlap risk" would require missing these exclusions.