Conciseness

Every line is a directive with no padding — e.g. "Never run CPU-heavy or I/O-bound code on the event loop... offload it with asyncio.to_thread" and "Async file wrappers don't make blocking syscalls non-blocking" assume Claude's competence and explain only Vibe-specific constraints. Anchor 5: every token earns its place.

Actionability

Each rule names concrete, executable APIs and paths: "asyncio.create_task + queues", "asyncio.to_thread", "anyio.Path", "VibeAsyncHTTPClient from vibe.utils.http", "respx" for mocking, plus the exact prohibition "do not resolve DNS before proxy selection". For an instruction-only conventions skill this is fully actionable guidance, which the rubric says should not be penalized for lacking code.

Workflow Clarity

This is a single-purpose conventions skill under 50 lines with no multi-step process and no destructive or batch operations, so the simple-skill exception applies: each section's single action is unambiguous. Anchor 5.

Progressive Disclosure

Under 50 lines, needs no external references, and is organized into clear topical sections (Runtime, Blocking work, Streaming, Core-to-client communication, HTTP clients). Per the rubric guideline, a short skill with no need for bundle files scores 5 with well-organized sections; no references/ or scripts/ files exist to reconcile.

Specificity

"Async and concurrency patterns" names the domain and enumerates concrete subsystems (asyncio, agent loop, HTTP clients, streaming surfaces, core-to-client communication), but no concrete capability actions are stated. Fits anchor 3 (domain plus limited specifics) rather than 4, which requires several specific actions.

Completeness

"Async and concurrency patterns for Mistral Vibe" states the what, and "Use when working with asyncio, the agent loop, the app server's event loop, HTTP clients, streaming surfaces, or core-to-client communication" is an explicit when-clause with multiple concrete triggers. This matches anchor 5; anchor 4's weaker 'when could be more explicit' does not apply given the specific multi-surface trigger list.

Trigger Term Quality

Natural triggers like "asyncio", "the agent loop", "the app server's event loop", "HTTP clients", "streaming surfaces" give good keyword coverage for this domain, but common variations such as "concurrent", "background tasks", "non-blocking", or "async/await" are missing. Anchor 4 (good coverage, a few natural terms missing) fits best.

Distinctiveness Conflict Risk

Scoped to Mistral Vibe with niche triggers (app server's event loop, streaming surfaces, core-to-client communication), giving a clear, distinct niche with minimal overlap risk against generic skills. Anchor 5.