Conciseness

The body is dense with repo-specific contracts and constraints — "A verifier returns (True, None) or (False, reason)", "Do not gate registration on enable switches; dispatch reads those at call time" — with zero filler and no explanation of concepts Claude already knows. Every sentence is a directive or a contract; it matches the lean, every-token-earns-its-place anchor, and no neighboring anchor (which would require padding or over-explanation) fits.

Actionability

Concrete, executable guidance dominates: exact decorator forms (`@register(entry, backend=TritonAscendBackend, verifier=...)`, `@register('<operation>')`, `env_var=...`), a mapping table for the two registration forms, a real env var (`FLA_DISABLE_BACKEND_DISPATCH=1`), and a runnable script (`scripts/find_dependent_tests.py`). It falls short of 5 because these are fragments rather than a complete copy-paste example of defining and registering a backend end-to-end, and above 3 because the guidance is concrete and executable, not pseudocode.

Workflow Clarity

Four numbered sections give a clear sequence (define calls → register → preserve routing → verify), and section 4 is a dedicated validation pass enumerating concrete scenarios (accepted calls, verifier rejection, disabled/unavailable backends, fallback, omitted vs supplied optional args, fresh processes for import order). It is below 5 because there is no explicit error-recovery feedback loop (e.g., what to do when the routing tests fail) and above 3 because validation checkpoints are explicit and thorough rather than implicit.

Progressive Disclosure

The skill is under 50 lines with no bundle files, and the body is organized into four well-labeled sections, which merits a 5 under the simple-skill exception. Its only external pointers — [CONTRIBUTING.md](../../../CONTRIBUTING.md) and [fla/backends.py](../../../fla/backends.py) — are clearly signaled, one level deep, and load immediately relevant context rather than deferring the actual instructions.

Specificity

The description lists several concrete actions — "Change FLA backend registration, dispatch, or verifiers" — plus an explicit constraint ("preserving routing and call contracts"), matching the anchor for several specific actions with minor gaps. It is not a 5 because coverage is incomplete relative to the body (e.g., backend selection/priority, testing through the entry point, adapter classes are not surfaced), and not a 3 because it names more than 1-2 actions.

Completeness

The "what" is clear (change backend registration, dispatch, or verifiers while preserving contracts), but there is no "Use when..." clause or equivalent trigger guidance in the description, which caps completeness at 3 per the judging guidelines. It is above 2 because the "what" is concrete and specific rather than vague, and below 4 because the "when" is only weakly implied by the domain framing.

Trigger Term Quality

Terms like "FLA backend", "registration", "dispatch", "verifiers", and "routing" are exactly what a developer working in this repo would say when they need this skill, giving good keyword coverage. It falls short of 5 because natural variations and concrete file/extension triggers (e.g., "backends.py", "register a kernel", "@dispatch") are missing, and it stays above 3 because the included terms are multiple and directly on-target rather than generic.

Distinctiveness Conflict Risk

"FLA backend registration, dispatch, or verifiers" carves out a clear niche with distinct triggers that no general-purpose skill would plausibly claim. It matches the anchor for a clear niche with minimal conflict risk; no neighboring anchor fits better since even closely related skills (e.g., generic Python testing skills) would not be triggered by these terms.