Conciseness

The body is lean and assumes Claude's competence: a two-line overview, six 'when to apply' bullets, an 8-row priority table, and a short file-usage explanation with external links. Nothing explains Postgres basics Claude already knows, and every section carries information (priorities, prefixes, file layout) that is not derivable from the description. It matches the top anchor 'every token earns its place'; 4 would require over-explanation worth trimming, and none is present.

Actionability

The navigation mechanism is partially concrete — the category table maps tasks to filename prefixes ("query-", "conn-", "security-"...) and the file inventory in references/ matches — but the body gives no executable SQL or commands itself and the 'How to Use' code block names only 3 of the 35 rule files, with no instruction for mapping a task to the right file or a complete index. It sits at 'some concrete guidance but incomplete; missing key details' rather than 4, which would require the lookup guidance to be complete with only minor gaps.

Workflow Clarity

The implied sequence (identify the task category → read the matching rule files → apply the incorrect/correct patterns) is present via the table and 'How to Use', but steps are never explicitly ordered and there are no validation checkpoints, e.g. no 'verify the fix with EXPLAIN ANALYZE' loop. Per the rubric's scoring notes, database-operation skills missing feedback loops are capped at 3; it is not 2 because the table-plus-prefix structure does convey a usable rough sequence.

Progressive Disclosure

The bundle structure is genuinely good: SKILL.md is a short overview, all detail lives in one-level-deep references/*.md rule files (verified to exist), and the prefix convention makes files discoverable. It falls short of 5 because the body points to only three arbitrarily chosen files out of 35 and includes _sections.md (an internal section-definitions file) in the 'How to Use' block without explaining it, leaving navigation partially implicit — 'references mostly clear; minor organization gaps'.

Specificity

The description enumerates many concrete capability domains — "creating or altering tables and columns (including choosing column types)", "migrations and declarative schema files", "RLS policies and the tests that verify them", "queues and scheduled jobs (pg_cron, pgmq)", "vector/semantic search (pgvector)", "restoring dumps (pg_restore)" — with comprehensive coverage of both authoring and diagnostic tasks. It names specific tools and operations rather than abstract language; score 4's "minor gaps in coverage" does not apply since no significant Postgres task area is missing.

Completeness

Both questions are explicitly answered: what — "Postgres best practices maintained by Supabase... schema, migration, security, and SQL authoring tasks need these rules too"; when — "Load this skill BEFORE writing or changing anything that lives in a Postgres database" and "Also load it when diagnosing slow queries, high CPU, timeouts...". Concrete trigger phrases accompany both, matching the 5 anchor exactly; 4 would require the 'when' to be less explicit, which it is not.

Trigger Term Quality

Natural user phrasing is comprehensively covered: "slow queries", "high CPU", "timeouts", "EXPLAIN plans", "connection exhaustion", "locking", "bloat", "migrations", "indexes", "importing data", plus tool names (pg_cron, pgmq, pgvector, pg_restore). These are exactly the words a developer would say when needing this skill; nothing common is missing, matching the top anchor.

Distinctiveness Conflict Risk

It occupies a clear niche (Postgres/Supabase database work) with distinct triggers — "rows visible to the wrong user or tenant", "pg_restore", "RLS policies" — that no generic document or general-coding skill would claim. The scope clarification "for Postgres running anywhere" further sharpens boundaries rather than blurring them; conflict risk is minimal.