Conciseness

The body is mostly lean code with minimal prose padding and no explanation of concepts Claude already knows (no 'Supabase is a backend-as-a-service...' boilerplate). Minor trimmable instances remain: the redundant opening line 'Debug and fix common Supabase issues.', comments restating the obvious ('// Check Docker is running'), and the ~30 lines of error-code tables that duplicate references/common-errors.md. Above anchor 3 ('some unnecessary explanation') but not the every-token-earns-its-place level of anchor 5.

Actionability

Nearly every section gives executable JavaScript/SQL/bash snippets (e.g., the RLS debug sequence with 'SET request.jwt.claims = ...' and 'SELECT auth.uid();', the realtime cleanup useEffect). A few snippets are illustrative fragments rather than copy-paste ready: 'const result = heavyComputation()'/'heavyComputationAsync()' are placeholder names, 'USING (user_id IN (SELECT ...))' appears without its CREATE POLICY wrapper, and '...values'/'{...}' ellipses appear in upsert and channel examples. Concrete with minor gaps — anchor 4, not fully executable anchor 5.

Workflow Clarity

A clear diagnosis flow exists (Quick Diagnosis symptom→cause table funneling into per-issue sections, with check steps like 'supabase status', the _health probe, and subscription status logging), but there are no validate-after-fix checkpoints for the database operations the skill performs. The scoring note caps workflow clarity at 3 when database operations lack feedback loops: e.g., 'SET log_statement = ...' (temporary, per its own comment) is never reverted, and CREATE POLICY examples aren't followed by a re-test step. Not anchor 2 — the sequence and per-symptom checks are well defined; anchor 4's 'most checkpoints present' is blocked by the missing verify-the-fix loop.

Progressive Disclosure

The single reference is real, one level deep, and clearly signaled in a dedicated '## References' section ('[common-errors.md](references/common-errors.md) - Error code reference'). However, substantial content that overlaps the reference file — the entire 'Common Error Codes' section of PGRST/PostgreSQL/auth tables — is inlined in a ~450-line body, matching anchor 3's 'content that should be separate is inline' rather than anchor 4's 'most content appropriately placed'.

Specificity

The description lists several specific issue areas — 'auth errors, RLS policies, connection problems, and performance' — under the concrete action 'Troubleshoot', with minor gaps (no mention of storage, edge functions, or realtime, which the body covers). It names several specific targets rather than the multiple distinct concrete actions of a 5 ('Extract text... fill forms, merge documents'), and is clearly above anchor 3's '1-2 concrete actions'.

Completeness

Both 'what' ('Troubleshoot common Supabase issues including auth errors, RLS policies, connection problems, and performance') and 'when' ('Use when debugging Supabase issues, fixing errors, or optimizing performance') are explicit, mirroring the anchor-5 example's structure of concrete capability list followed by an explicit 'Use when...' trigger clause with concrete trigger phrases.

Trigger Term Quality

Good natural keyword coverage: 'debugging Supabase issues, fixing errors, or optimizing performance' plus 'auth errors', 'RLS policies', 'connection problems' — phrases users would naturally say. Falls short of anchor 5's comprehensive synonym coverage (e.g., missing variations like 'Supabase slow', 'Supabase error', 'supabase not working'), but exceeds anchor 3's 'missing common variations'.

Distinctiveness Conflict Risk

'Supabase' is a clear niche identifier appearing in both the what and when clauses, with distinct triggers (auth errors, RLS, connection, performance) all tied to that product. Minimal conflict risk with any other skill — it would not trigger for non-Supabase debugging.