Conciseness

The body is lean and assumes competence — it adds only FRB-specific facts (the frb_dump location, the RUST_LOG prefix, the frb-fix-ci ordering rule) with no padding or explanation of concepts Claude already knows. Minor trims remain (the "..." in the dump-artifacts list and the typo "for debugability"), placing it at anchor 4 rather than a fully token-tight 5.

Actionability

Some guidance is concrete ("check rust/target/frb_dump/", "RUST_LOG=debug flutter_rust_bridge_codegen"), but the codegen command ends in an ellipsis instead of executable arguments, the artifact list ends in "...", and the Full Troubleshooting section is just two bare repo paths with no instruction on what to do with them. This matches anchor 3 ('some concrete guidance but incomplete... missing key details') and falls short of anchor 4's mostly-executable standard.

Workflow Clarity

A rough sequence is present — quick diagnostics first, then full troubleshooting, with an explicit ordering rule ("You MUST only stay in frb-debugging after frb-fix-ci has ruled out those simpler explanations") — but there are no explicit checkpoints validating a hypothesis at each stage (e.g., what to confirm in the dump before escalating to internals). Anchor 3 ('sequence present but checkpoints missing or implicit') is the best fit; not 4 because the checkpoints are never stated.

Progressive Disclosure

For a sub-50-line skill with no bundle files, the body is well organized into clearly labeled sections (When to Use, Quick Diagnostics, Full Troubleshooting, Related Skills) with one-level-deep, clearly signaled pointers ("see: website/docs/manual/troubleshooting.md", related skills). Minor gap: the referenced paths live outside any bundle and it is implicit that they are repo-relative rather than skill files, keeping it at anchor 4 rather than 5.

Specificity

The description lists concrete trigger scenarios ("generated code looks wrong", "code generation fails") but names zero actions the skill performs — there is no 'what' verb like diagnoses, dumps, or traces. It sits at anchor 2 ('names the domain but actions are minimal or generic'), below anchor 3 since no concrete skill actions are given, and above anchor 1 because the scenarios are specific rather than pure abstract fluff.

Completeness

"Use when..." explicitly answers the 'when' with concrete trigger phrases, but the description never states what the skill actually does. Per the rubric, a description with a clear 'when' but missing 'what' fits anchor 2 ('only when is present without what'); it does not reach anchor 4, which requires both.

Trigger Term Quality

"Code generation fails" and "generated code looks wrong" are natural user phrases, but common variations users would actually say — "debug", "flutter_rust_bridge", "rust", "generated code errors" — are absent. This matches anchor 3 ('some relevant keywords but missing common variations or synonyms') and falls short of anchor 4's good keyword coverage.

Distinctiveness Conflict Risk

"Understand FRB internals" carves a clear niche with minimal conflict risk, but the generic triggers "generated code looks wrong" and "code generation fails" could plausibly fire for other code-generation skills. Anchor 4 ('mostly distinct; minor overlap risk with closely related skills') is the best fit; not 5 because those generic triggers are not fully distinct.