Conciseness

Every line is a prescriptive rule carrying non-obvious project-specific knowledge (e.g. "lower means higher priority", "keep backend selection logic outside compiled graphs", "do not rely on the cached can_use() path"). No padding and no explanation of concepts Claude already knows, so it matches the 'every token earns its place' anchor.

Actionability

The checklist gives exact steps with concrete identifiers: "Add a BaseBackend subclass under the operation's backends/ package", "Set backend_type, package_name, env_var, default_enable, and priority", "Implement <public_function_name>_verifier(...)", "Register the backend in the operation's backends/__init__.py", plus runnable env-var commands and the concrete helper path scripts/find_dependent_tests.py. Per the scoring notes, an instruction-only skill with this level of specific guidance earns full marks despite having no code blocks.

Workflow Clarity

The 'Backend implementation checklist' is a clear 6-step sequence with a testing step ("Add tests that cover accepted dispatch, verifier rejection, and fallback") and the testing section adds per-branch rejection-test requirements. Not score 5 because there is no explicit validate-then-fix feedback loop (e.g. 'run the op tests, fix, re-run') tying the checklist to verification.

Progressive Disclosure

A single-file skill with no bundle files, organized into six clearly headed sections (Core model, Backend implementation checklist, Verifier rules, Decorator placement, Testing guidance, Style constraints) that are each short and navigable. Not score 5 because the body runs well past 50 lines, so sections like Verifier rules or Style constraints could arguably live in reference files if the skill grew.

Specificity

"Workflow for FLA backend dispatch decorators and backend implementations" names the domain concretely but describes no concrete actions (no verbs like 'add', 'implement', 'register'). It is not score 2 because the domain is precisely scoped rather than generic, and not score 4 because the 'what' is a single abstract noun phrase with no enumerated capabilities.

Completeness

Both halves are present: a 'what' ("Workflow for FLA backend dispatch decorators and backend implementations") and an explicit 'Use when...' clause with concrete triggers, which avoids the score-3 cap for missing trigger guidance. Not score 5 because the 'what' states what the skill is rather than what it concretely does, so it is less explicit than the anchor-5 example that enumerates actions.

Trigger Term Quality

Terms like "fla.ops.backends", "@dispatch-decorated functions", "BaseBackend subclasses", "backend verifier methods", "backend env vars, or backend tests" are exactly what a developer touching this code would say. Not score 5 because a few natural variants are absent (e.g., the escape-hatch env var FLA_DISABLE_BACKEND_DISPATCH, 'registry', 'priority', specific backend flags like FLA_TILELANG).

Distinctiveness Conflict Risk

"FLA backend dispatch decorators", "BaseBackend subclasses", and "backend verifier methods" define a clear niche with distinct triggers that no generic skill would match. Minimal conflict risk with any other skill.