Conciseness

The body is lean: a priority table, six short trigger bullets, and a brief description of the rule-file format, with no padding or explanations of concepts Claude already knows. It misses anchor 5 only because the opening paragraph and "When to Apply" bullets restate the frontmatter abstract/description, a small redundancy that could be trimmed.

Actionability

Guidance is structural rather than executable: "Read individual rule files for detailed explanations and SQL examples" plus a prefix naming convention and three example paths. The convention lets Claude infer file names, but the body never says how to map a task to a specific rule file, and only 3 of the 35 reference files are shown — matching anchor 3's 'some concrete guidance but incomplete' rather than anchor 4's mostly-executable direction.

Workflow Clarity

There is no sequenced procedure: the implied flow is "check When to Apply → find the relevant rule file → apply it", but which rule file to open for a given problem (e.g. a slow query vs. pool exhaustion) is left implicit, and no validation or verification steps are described. Per the simple-skill exception this could score higher, but the single action — selecting the right reference — is ambiguous, capping it at anchor 3.

Progressive Disclosure

SKILL.md is a genuine overview: a category/priority/prefix table, a description of each rule file's contents, and one-level-deep references (references/query-missing-indexes.md, references/schema-partial-indexes.md, references/_sections.md — all verified to exist) alongside 35 flat rule files. It falls short of anchor 5 because only three arbitrary example paths are listed rather than a complete or per-category index, and meta files (_contributing.md, _template.md) are present in the bundle but unexplained.

Specificity

The description names the domain ("Postgres performance optimization and best practices from Supabase") and the artifacts it covers ("Postgres queries, schema designs, or database configurations"), but the actions themselves are generic — "optimization and best practices" names no concrete operations like index creation, pooling configuration, or RLS tuning. It sits between anchor 2 (generic actions) and anchor 3 (1-2 concrete actions), matching anchor 3's breadth of scope without anchor 4's specific action list.

Completeness

The "when" is explicit and concrete ("Use this skill when writing, reviewing, or optimizing Postgres queries, schema designs, or database configurations") with multiple trigger activities, and the "what" is stated ("Postgres performance optimization and best practices from Supabase"). It falls short of anchor 5 only because the "what" is a single generic capability rather than multiple concrete actions, matching anchor 4's 'when could be more specific / what is adequate' profile.

Trigger Term Quality

Natural trigger terms are present: "Postgres", "queries", "schema designs", "database configurations", "performance", and "Supabase" — phrases a user would plausibly say. Common synonyms like "SQL", "slow queries", "indexes", or "database performance" are missing, which keeps it below anchor 5's comprehensive synonym and extension coverage.

Distinctiveness Conflict Risk

The Supabase/Postgres performance niche is clearly staked with distinct triggers (Postgres queries, schema design, database configuration), and the Supabase attribution further narrows it. Overlap with generic SQL or database-admin skills is minimal, matching anchor 5.