Conciseness

The body is efficient and assumes competence — it carries non-obvious knowledge (close-code table, port: 0 pattern, retryAttempts: 0, --forceExit rationale) with no basic-concept padding. Minor trim opportunities exist: the "How to use" steps restate the Authoring sections, and sibling-skill scope is stated in both "When to use" and "References".

Actionability

Fully executable inline TypeScript for both transports, install commands, jest config, CI workflow YAML, and a concrete worked example; the only undefined helpers (startWsServer/startSseServer) are implemented in the clearly signaled reference files. Code is copy-paste ready and covers the common subscription test cases.

Workflow Clarity

"How to use" gives an explicit 7-step sequence (install, port: 0 server, client.iterate, errors-before-data assertion, auth rejection codes, resolver isolation, CI timeout/forceExit) with checkpoints such as checking errors === undefined and the anti-patterns table. It stops short of a 5 because there is no explicit validate→fix→retry feedback loop for recovering from failures.

Progressive Disclosure

The SKILL.md body stays a lean overview and points to four well-signaled, one-level-deep reference files (transport-server-setup, auth-on-connect, lifecycle-and-close-codes, resolver-and-filter-tests), all of which exist with real content and no nested references. Content is appropriately split and easy to navigate.

Specificity

The description lists multiple concrete actions — "subscribing through the async iterator, asserting event shape and order, connection lifecycle and close codes, auth on connect and pubsub triggers" — giving comprehensive coverage of the subscription-testing niche. It exceeds the score-4 anchor because every major test category for the domain is named rather than having minor gaps.

Completeness

It opens with an explicit "Use when GraphQL subscriptions need tests over graphql-ws (WebSocket) or graphql-sse" trigger clause and pairs it with a concrete list of what the skill does. Both what and when are explicitly answered with concrete trigger phrases, matching the top anchor.

Trigger Term Quality

Natural keywords like "GraphQL subscriptions", "graphql-ws", "graphql-sse", "WebSocket", "auth on connect", and "pubsub triggers" match what a user would say. A few natural synonyms ("SSE" spelled out, "Server-Sent Events", "real-time", "live updates") are missing, so it falls just short of the comprehensive-synonym anchor.

Distinctiveness Conflict Risk

The niche is clear (subscription transport testing via graphql-ws/graphql-sse) and it explicitly delimits boundaries — "Queries and mutations belong to the server test skills" — so conflict with sibling server-test skills is minimal.