Conciseness

The body is largely lean — tables, dense executable pytest snippets, an anti-patterns table, and a limitations section that each earn their tokens — but there is minor over-explanation: the Overview paragraph re-explains that gRPC has four streaming patterns (concepts Claude already knows), and the 'Unary (covered for completeness)' section spends two full test examples on a pattern the description doesn't even claim. Matches 'efficient; minor instances of over-explanation that could be trimmed', not 5.

Actionability

Server-streaming is exhaustively covered with copy-paste-ready pytest code, a concrete coverage matrix, a per-language harness table, and an output directory layout. Not a 5: the `stub_with_fake` / `stub_with_slow_fake` fixtures are never defined in the bundle (delegated to the external `grpc-mock` skill), and client-streaming and bidi — two of the four patterns — have no inline executable example, only pointers to reference skeletons, leaving minor gaps.

Workflow Clarity

Steps 1–5 are clearly sequenced (classify → per-pattern categories → coverage matrix → harness → emit directory) and the matrix rule 'Empty cells in covered patterns = coverage gap. PR must justify or add a test' acts as a checkpoint. Falls short of 5 because there is no explicit validation step — nothing instructs running the generated suite or verifying the tests compile/pass against the in-process server before finishing.

Progressive Disclosure

SKILL.md is a genuine overview: representative Python examples inline, with per-language skeletons, the 17-code status matrix, and wire-level patterns each split into a real, substantive reference file, all one level deep and clearly signaled both inline and in a References section. This matches 'clear overview with well-signaled one-level-deep references; content appropriately split; easy navigation'.

Specificity

The description lists multiple concrete capabilities: writing tests and auditing suites for "ordering, completion, cancellation, deadlines and partial failures", "skeletons for Go, Python, JVM and Node", and "the 17 gRPC status codes and their retry rules". This matches the anchor for multiple specific concrete actions with comprehensive coverage; the only reason to consider 4 is that actions are framed inside the trigger clause, but the deliverables are explicitly enumerated.

Completeness

Both what and when are explicit: "Use when a server-streaming, client-streaming or bidirectional gRPC call needs tests, or a suite needs auditing for gaps" gives concrete trigger conditions, and the what is spelled out (test authoring/auditing across the listed categories, per-language skeletons, status-code and retry rules). Matches the anchor 'clearly and explicitly answers both what AND when with concrete trigger phrases'; a 4 would require the when to be less explicit than it is.

Trigger Term Quality

Strong natural keywords a user would actually say: "gRPC", "server-streaming", "client-streaming", "bidirectional", "tests", "cancellation", "deadlines", "status codes". Not a 5 because common variations and file extensions are missing — no ".proto"/"proto file", no "streaming RPC" phrasing, and "JVM" is less natural than "Java" — so it falls at 'good keyword coverage; a few natural terms missing'.

Distinctiveness Conflict Risk

It carves out a clear niche — authoring/auditing tests for gRPC streaming RPCs specifically — with distinct triggers (the three streaming pattern names, cancellation, deadlines, status codes) that would not fire for unrelated skills. Minor overlap potential with general gRPC or contract-testing skills exists, but the streaming-test framing is unmistakable, matching the 'clear niche with distinct triggers' anchor.