Conciseness

The body is almost entirely executable code blocks and tables with no concept explanations — it assumes Claude's competence and never pads with prose like 'Supabase is a platform that...'. Minor trims are possible (pagination is demonstrated twice via query params and the Range header, and the JS quick reference partially re-covers ground Claude already knows), which keeps it at anchor 4 rather than the 'every token earns its place' anchor 5.

Actionability

Everything is copy-paste ready: install command, four complete createClient variants, curl commands with exact headers for every REST CRUD operation, executable auth/storage/realtime/edge-function snippets, a filter-operator table with concrete query examples, and an error-codes table. This matches 'Fully executable; copy-paste ready code or commands; specific examples cover the common cases'.

Workflow Clarity

This is a reference skill with no multi-step workflows, and an Error Handling section with an `if (error)` pattern and a codes table gives some recovery guidance. However, the destructive and database operations (DELETE, upsert with merge-duplicates, PATCH) include no validation or verify-then-retry loop — no guidance to check the row exists, use return=representation to confirm the affected row, or handle partial failures — so per the rubric's cap for database operations without feedback loops, workflow clarity cannot exceed 3.

Progressive Disclosure

The one bundle file (references/client-patterns.md, verified present) is real, one level deep, and clearly signaled via a '## References' section with a descriptive label. But the body itself is 352 lines of inlined API reference — auth, storage, realtime, filter operators, and type helpers are detail that belongs in reference files while SKILL.md stays an overview. This matches 'content that should be separate is inline' at anchor 3; the good section headers keep it from scoring 2.

Specificity

The description names the domain ('Supabase JavaScript client API and REST API usage') and a couple of semi-concrete actions ('setting up clients', 'using REST endpoints directly'), but the what-clause is a generic noun phrase ('API usage') rather than a list of concrete capabilities. It matches the anchor 'Names domain and 1-2 concrete actions, but not comprehensive' — it lacks the enumerated actions (querying tables, auth, storage, realtime) that would justify a 4.

Completeness

Both what and when are present, and the 'Use when integrating Supabase, setting up clients, or using REST endpoints directly' clause is explicit with concrete triggers. It falls just short of anchor 5 because the what-clause ('API and REST API usage') is noticeably less action-concrete than the anchor-5 exemplar, which lists specific actions before the 'Use when' clause.

Trigger Term Quality

The core natural term 'Supabase' is present and reinforced by 'client' and 'REST endpoints', but common variations a user would actually say are missing — database, queries, auth, storage, realtime, Postgres. This fits 'Some relevant keywords but missing common variations or synonyms' rather than the good-coverage anchor 4.

Distinctiveness Conflict Risk

'Supabase' is a distinct named product and the description carves a clear niche (JS client + REST API usage) with product-specific triggers; virtually no other skill would fire on these terms. This matches the anchor 'Clear niche with distinct triggers; minimal conflict risk'.