Conciseness

The body is dense and operational - table-formatted anti-patterns, terse step headings, no explanations of concepts Claude already knows. Not 5 because of minor trimmable material: the full Maven <plugin> XML block, the complete CI job YAML, and pinned time-sensitive version numbers (liquibase/liquibase:5.0.4, postgres:17) that will age; not 3 because there is no padding or generic library explanation.

Actionability

Fully executable throughout: a complete docker run command with env-var password handling, 'mvn liquibase:validate liquibase:update', complete YAML changesets with rollback sections, the four-command gate, and a copy-paste CI job. Not 4 because the common cases (create table, add column, preconditions, contexts, includes, CI) are all covered by runnable examples, with only trivial ellipses ('columns: [...]') remaining.

Workflow Clarity

Steps 1-8 are clearly sequenced, and Step 3 is an explicit validation gate ('Run these in order; stop at the first failure': validate, status --verbose, update-sql, update) with feedback loops for the two real failure modes - checksum errors (revert, new changeset, validCheckSum with justification) and held locks (release-locks). Not 4 because validation checkpoints and error recovery are explicit, which matters for destructive database operations.

Progressive Disclosure

The single SKILL.md is well-sectioned with a clearly signaled one-level-deep References list of external doc links, and no bundle files exist to nest. Not 5 because it is a ~300-line monolith where content such as the full CI job YAML, Maven plugin configuration, or the precondition/label catalogs could be split into reference files; not 3 because structure and navigation within the file are good.

Specificity

The description lists multiple concrete capabilities - "changelogs and changesets in XML, YAML, JSON or SQL", "update, status, rollback and tag", "preconditions, contexts and labels", and "the changelog lock tables" - with comprehensive coverage and no vague filler. It exceeds the 4 anchor because coverage is comprehensive rather than having minor gaps.

Completeness

Explicitly answers both questions: "Use whenever a schema is managed with Liquibase" gives a clear when-trigger, and the enumerated capabilities plus "portable migrations across databases with fine rollback control" give a concrete what. Not 4 because the when-clause is explicit, not merely implied.

Trigger Term Quality

Good keyword coverage with natural domain terms users would say: "Liquibase", "changelog", "changeset", "rollback", "migrations", "schema". Not 5 because it lacks filename/extension triggers (e.g. db.changelog-master.xml, changelog.yaml) and common synonym phrasing; not 3 because the core vocabulary is rich and natural.

Distinctiveness Conflict Risk

The trigger is scoped to a named tool ("managed with Liquibase") with tool-specific vocabulary (changesets, DATABASECHANGELOG lock tables), giving a clear niche with minimal overlap risk against sister tools like Flyway or Atlas. Not 4 because no closely related skill would capture these triggers.