Conciseness

The body is largely lean and imperative — it assumes Claude knows how to debug and never explains basic concepts — but contains minor trimmable material: the dated incident citation "来源：2026-04-05 runtime 状态误判教训" and environment-specific port defaults "`3003/3004` 默认是 runtime", which per guidelines count as time-sensitive clutter outside a deprecated/old-patterns section. Not anchor 5 for those tokens; not anchor 3 because the padding is minor, not a pattern of over-explanation.

Actionability

Concrete, executable guidance is present: real commands (`lsof -nP -iTCP:<实际端口> -sTCP:LISTEN`, `ps -p <PID> -o lstart=`), a fill-in instance-forensics template, a concrete output path (`docs/bug-report/<bug-name>/bug-report.md`), and specific cross-skill handoffs (`tdd`, `writing-plans`, `quality-gate`). It falls short of anchor 5 because several directives depend on unverifiable environment context — "search_evidence", "决策漏斗", "Alpha 通道", "找合适伙伴" — that gives no actionable step outside that environment.

Workflow Clarity

The four-phase investigation (根因调查 → 模式对比 → 假设实验 → 修复验证) is clearly sequenced with explicit validation in phase 4 ("确认 RED 真实覆盖问题…复验同一信号与受影响路径") and feedback loops ("出现新症状时回查机制", "结果不支持就更新假设"), plus a repeated-failure escalation section. Not anchor 5 because the sequence is deliberately optional ("可以…换方法") and hard requirements live in a separate unnumbered list, leaving the definitive workflow slightly diffuse; clearly above anchor 3 since checkpoints are explicit, not missing.

Progressive Disclosure

The ~75-line body is well-sectioned with clear optional-vs-required separation, and its only external references — [../.cat-cafe-shared-refs/bug-diagnosis-capsule.md] and ../.cat-cafe-shared-refs/shared-rules.md §12/§16a — are one level deep and clearly signaled; no bundle files exist to organize. Not anchor 5 because the body exceeds the ~50-line simple-skill threshold and both referenced paths are broken (the shared-refs directory does not exist in the workspace), which breaks navigation; not anchor 3 because structure and reference signaling are otherwise good.

Specificity

The description names several concrete actions — "根据证据定位未知根因并验证修复" (locate unknown root cause from evidence and verify the fix) and "未解决时给出真实缺口和下一步" (report real gaps and next steps when unresolved) — which goes beyond naming the debugging domain. It falls short of anchor 5 because coverage is not comprehensive (e.g., no mention of reproduction, hypothesis testing, or isolation of causes as discrete actions).

Completeness

It explicitly answers both what ("根据证据定位未知根因并验证修复") and when ("Use when: bug、测试失败或异常行为的根因尚未查明") with concrete trigger phrases, and adds an explicit Output and a Not-for boundary redirecting known-cause fixes to `tdd`. This matches anchor 5 and clearly exceeds anchor 4, where the 'when' would be only loosely specified.

Trigger Term Quality

It includes natural phrases users would actually say — "bug", "测试失败" (test failure), "异常行为" (unexpected behavior) — reinforced by a triggers list with "debug" and the synonym "报错". Not anchor 5 because common variations such as "error", "crash", "exception", or "stack trace" are absent.

Distinctiveness Conflict Risk

It carves a clear niche — unknown root causes only — and the explicit "Not for: 新功能设计、已确定原因且有精准失败检查的修复（用 tdd）" clause resolves overlap with the closely related `tdd` skill, leaving minimal conflict risk. Anchor 4 would apply if overlap with related skills remained unresolved, but the Not-for clause handles it directly.