Conciseness

The body is lean and dense with project-specific facts Claude could not know: named views ("contacts_summary", "companies_summary"), named shared utils, the middleware chain order, and a specific migration ID. It explains no general concepts, assumes competence throughout, and every line carries non-obvious information — matching 'every token earns its place'. Not a 4 because there are no trimmable over-explanations anywhere.

Actionability

Mostly concrete, executable guidance: exact view names, file paths in `supabase/functions/_shared/`, the `verify_jwt = false` config setting, an inline call pattern (`httpClient(`${supabaseUrl}/functions/v1/<name>`)`), and named conventions (e.g. `mergeContacts()` → `/functions/v1/merge_contacts`). It stops short of anchor 5's 'copy-paste ready' bar because the code shown is fragments and naming patterns rather than complete, runnable examples (e.g. no full edge-function skeleton or RLS policy snippet), though for a conventions-reference skill the gaps are minor.

Workflow Clarity

The entry instruction sequences the process explicitly — 'Read the relevant section before writing backend code, then check the Red Flags and Verification list' — and the skill closes with a 6-item verification checklist covering exactly its risky operations (view sync, RLS/trigger on new tables, SECURITY DEFINER counts, WITH CHECK column coverage, middleware order). Validation checkpoints are explicit and comprehensive, matching the anchor-5 pattern of clear sequence plus checklists; there are no missing-validation gaps that would cap it at 3 or 4.

Progressive Disclosure

No bundle files exist (no references/, scripts/, or assets/), and none are needed: the ~55-line body is a genuinely lean overview with well-organized sections, and detailed material is delegated via clearly signaled one-level pointers to sibling skills (`Skill({skill: "writing-migrations"})`, `Skill({skill: "frontend-dev"})`). Under the rubric's guidance for short skills with no need for external references, well-organized sections alone warrant a 5, and nothing here should have been split out.

Specificity

The description names the domain ("backend development in Atomic CRM") and enumerates concrete artifacts — "database migrations, views, triggers, RLS policies, edge functions, or custom dataProvider methods" — which is several specific actions with only minor gaps. It falls short of a 5 because the leading "what" ("Coding practices") is somewhat abstract and the verbs are generic ("creating/modifying"), rather than fully distinct concrete actions.

Completeness

Both halves are explicit: the "what" ("Coding practices for backend development in Atomic CRM") and a concrete "Use when..." clause with specific triggers ("deciding whether backend logic is needed, or when creating/modifying database migrations, views, triggers, RLS policies, edge functions..."). This mirrors the anchor-5 good example's structure of clear what + explicit when with concrete trigger phrases; a 4 would require the 'when' to be less explicit, which it is not.

Trigger Term Quality

Strong natural keywords a developer would actually say: "backend", "database migrations", "views", "triggers", "RLS policies", "edge functions", "Supabase". A few natural variations are missing (e.g. "Postgres", "SQL", "RPC", "auth"), so it matches 'good keyword coverage; a few natural terms missing' rather than the comprehensive-synonyms anchor at 5.

Distinctiveness Conflict Risk

Scoping to "Atomic CRM" and Supabase-specific terminology ("RLS policies", "edge functions", "dataProvider") gives it a clear niche with minimal conflict against generic skills. Minor overlap risk remains with closely related sibling skills — the body itself delegates migration mechanics to a separate "writing-migrations" skill, yet the description claims "creating/modifying database migrations" as a trigger — which keeps it at 'mostly distinct; minor overlap risk' rather than 5.