Conciseness

Mostly dense with genuinely non-obvious facts (region footguns, consistency semantics, scope behavior), but the trailing "house rules" section restates six rules already covered above ("Blobs is not a database", "no built-in access control", the site-scope footgun, CLI commands, the counters warning, build-plugin read/write halves), and the scope warning appears three times total. Not 4 — the duplication goes beyond minor trimming; not 2 — the padding is repetition of real guidance, not explanation of concepts Claude already knows.

Actionability

Fully executable, copy-paste-ready TypeScript for the common cases: store writes/reads with type options, a complete upload Function with formData and uuid keys, a 404-returning read Function, conditional writes with onlyIfNew/onlyIfMatch checking modified, listing with directories/prefix/pagination, an expiration pattern, and the migration CLI command. Not 4 — examples cover the common cases completely with concrete failure handling (null checks, 400 responses).

Workflow Clarity

Explicit checkpoints are called out in bold ("Null-check before destructuring", checking `modified` and returning 400 on stale/exists, comparing the full ETag for freshness), giving clear validate-then-act sequences for reads and conditional writes. Not 5 — destructive operations (deleteAll, region migration, store deletion) have no verification steps; not 3 — validation is present and explicit for the core read/write/update flows, so gaps are minor.

Progressive Disclosure

Good section headers and two clearly signaled external links (CLI command reference, Netlify Blobs docs), but the body is ~240 lines of inlined API reference — regions, consistency, constraints, file-based uploads, and migration detail would fit a references/ file. Not 4 — this matches the anchor of ~200 lines of API reference inline that could live in a separate file with the SKILL.md as overview; not 2 — the structure is well-organized and references are not buried.

Specificity

Lists multiple concrete actions with comprehensive coverage: "Store and retrieve unstructured objects, files, and cache-like state" plus "persisting user file uploads", "caching computed output", "serving downloadable assets", "storing JSON blobs keyed by ID", and "seeding deploy-specific data". Not 4 — there are no minor gaps in the action coverage; it spans write, read, cache, and seed use cases.

Completeness

Explicitly answers both what ("Store and retrieve unstructured objects, files, and cache-like state on Netlify with the @netlify/blobs module") and when ("Use when persisting user file uploads... Triggers include...") with concrete trigger phrases. Not 4 — the when clause is fully explicit, not merely present.

Trigger Term Quality

Explicit natural trigger phrases users would say: "save an uploaded file", "cache API results", "store generated site map", "key/value store for a function", "file uploads without a database", reinforced by synonyms (objects, files, cache-like state, key/value, object storage, JSON blobs). Not 4 — coverage includes both plain-language phrases and technical synonyms, so no natural terms are meaningfully missing.

Distinctiveness Conflict Risk

Clear niche (Netlify blob/key-value storage) with explicit disambiguation "not for per-user, transactional, or relational data (use Netlify DB for that)", minimizing wrong-skill triggering. Not 4 — the negative boundary plus quoted triggers leave minimal overlap risk.