Conciseness

The body is almost entirely tables, terse SQL snippets, and one-line explanatory comments (e.g. the index cheat-sheet table, "-- SELECTでラップ！", "-- O(1) vs OFFSET は O(n)") with zero space spent explaining what PostgreSQL is or how basic concepts work. This matches anchor 5 ("Lean and efficient; assumes Claude's competence; every token earns its place"); the one-line intro and trailing attribution are minimal and do not constitute the padding that would drop it to 4.

Actionability

Every pattern is copy-paste-ready executable SQL: index DDL per query pattern, a complete antipattern-detection query set against pg_constraint/pg_stat_statements/pg_stat_user_tables, a working FOR UPDATE SKIP LOCKED queue UPDATE, an ON CONFLICT upsert, and ALTER SYSTEM config templates. This matches anchor 5 ("Fully executable; copy-paste ready code or commands; specific examples cover the common cases"); it is not 4 because the snippets are complete rather than having minor gaps — table aliases like `t` are placeholders, not missing detail.

Workflow Clarity

This is a lookup/reference skill rather than a multi-step workflow, and the sections are individually unambiguous, but it includes database operations with no validation or verification checkpoints: `ALTER SYSTEM SET max_connections/work_mem`, `REVOKE ALL ON SCHEMA public`, and the queue-processing UPDATE are applied with no "verify first" step (e.g. EXPLAIN before indexing, pg_reload_conf/testing before config changes). The scoring notes list database operations as a context where missing feedback loops cap workflow_clarity at 3, and that cap takes precedence over the simple-skill exception, so this is 3 ("Steps listed but validation gaps") rather than 4 or 5.

Progressive Disclosure

The single-file body (~140 lines) is well organized with clear section headers (quick reference tables, patterns, antipattern detection, config templates, related resources) and no nested or dead references — the `database-reviewer`, `clickhouse-io`, and `backend-patterns` pointers are cross-links to agents/skills, not broken file paths. This fits anchor 4 ("Good structure; most content is appropriately placed; minor organization gaps"); it is not 5 because at this length the antipattern-detection queries and config templates are plausible candidates for separate reference files, and not 3 because nothing is badly buried or misfiled.

Specificity

The description "PostgreSQL database patterns for query optimization, schema design, indexing, and security" names the domain clearly and enumerates four capability areas, but these are topic categories rather than concrete actions (no verbs like "optimize queries", "create indexes", "write RLS policies"). This sits between anchor 3 ("Names domain and 1-2 concrete actions, but not comprehensive") and anchor 4 ("Lists several specific actions") — closer to 3 because nothing is stated as an action Claude performs.

Completeness

The 'what' is reasonably clear ("PostgreSQL database patterns for query optimization, schema design, indexing, and security"), but there is no 'Use when...' clause or equivalent trigger guidance anywhere in the description — "Based on Supabase best practices" is provenance, not a trigger. Per the judging guidelines, a missing explicit trigger clause caps completeness at 3, which matches anchor 3 ("Has a clear 'what' but 'when' is missing or only weakly implied").

Trigger Term Quality

Terms like "PostgreSQL", "query optimization", "schema design", "indexing" are relevant, but common natural phrases a user would actually say — "slow query", "migration", "RLS", "row level security", "EXPLAIN", "database performance" — are absent. This matches anchor 3 ("Some relevant keywords but missing common variations or synonyms"); not 4 because the keyword set is limited to the four headline topics with no synonyms or tool-specific extensions.

Distinctiveness Conflict Risk

"PostgreSQL" plus the Supabase attribution carves out a clear niche with distinct triggers, and the named subtopics keep it from conflicting with generic SQL or other-database skills. Minor overlap risk remains with closely related database skills (the body itself links sibling skills like `clickhouse-io`), so this fits anchor 4 ("Mostly distinct; minor overlap risk with closely related skills") rather than 5 ("Clear niche with distinct triggers; minimal conflict risk").