Conciseness

The body is dense with project-specific, non-obvious rules (Spring Boot 4's flyway starter split, Flyway 10 database modules, checksum-based immutability of applied scripts) and never explains basics, so it is well above the midpoint. It is not 5 because several multi-line rationale passages ("A migration that never runs is worse than none...", the column-by-column spread argument, which partially repeats the frontmatter) could be tightened to one line each without losing guidance.

Actionability

Fully executable guidance throughout: a copy-paste-ready example migration (CREATE SEQUENCE / CREATE TABLE with CHECK, UNIQUE, and a marker comment), exact naming patterns ("{table_name}_seq", "V001__create_room_type_table.sql"), a concrete SQL marker snippet, and a fill-in Handover template. It is not 4 because the concrete examples cover the common cases end to end.

Workflow Clarity

The 9-step workflow has an explicit validation checklist in step 7, an executed build check, and a genuine feedback loop — "When a check or the build fails, fix the new migration — it has not run anywhere yet — and repeat this step until both pass" — plus destructive-operation guards (drops require user confirmation). Database operations get the validation loop the rubric requires, so it is not 4.

Progressive Disclosure

Both referenced files (references/layer.md, references/markers.md) exist, are exactly one level deep, and are clearly signaled with what they contain and when to consult them; the Markers-table rows are correctly split out of the body, and the two external documentation links are well placed. The body retains only execution-time rules, so nothing that belongs in a bundle file is inlined — matching the 5 anchor rather than 4.

Specificity

The description names multiple concrete, artifact-level actions — "versioned V*.sql scripts with sequences, tables, snake_case columns, CHECK and UNIQUE constraints, and foreign keys", "ALTER TABLE only where an existing table lags behind the entity model", and "Marks a constraint that enforces a business rule with -- UC-XXX BR-YYY" — giving comprehensive coverage of what the skill produces. It is not 4 because the action list is exhaustive rather than having minor gaps.

Completeness

The "what" is explicit and detailed (builds the migration layer: complete tables for new entities, ALTER TABLE for lagging ones, business-rule markers) and the "when" is an explicit 'Use when' clause with concrete quoted trigger phrases and scope limits ("in a project that combines layer plugins"). Both what and when are answered explicitly with triggers, matching the 5 anchor.

Trigger Term Quality

Trigger coverage includes natural user phrasings ("create a migration", "write a Flyway migration", "add a column", "set up the database schema") plus synonyms ("schema migration, DB migration, database versioning, or SQL migration files") and the V*.sql file pattern. It is not 4 because both natural phrases and synonym variations are comprehensively present.

Distinctiveness Conflict Risk

It carves a clear niche (Flyway schema-migration layer of a layered plugin process) and actively disambiguates against neighbors — "Test data migrations belong to the test skills" and "Never touches: the persistence, service, API, and UI layers". It is not 4 because the exclusions leave minimal overlap risk with adjacent skills.