Conciseness

The body is 13 lines with zero padding: it assumes Claude knows what a background agent or a Markdown file is and spends every token on instructions Claude could not infer ("每个 claim 都要追溯到拥有该事实的 source", "匹配现有 convention"). This matches the anchor 'lean and efficient; assumes Claude's competence; every token earns its place'; a 4 would require minor over-explanation to trim, which is absent.

Actionability

For an instruction-only skill the guidance is concrete: enumerated source types ("official docs、source code、specs、first-party APIs"), a per-claim traceability rule, a specified output format (Markdown with per-claim source attribution), and a save-location rule with an explicit fallback ("如果没有 convention，就放在合理位置并说明路径"). It falls short of 5 because the agent-launch step is stated only as "启动一个 background agent" with no invocation example or output-note template, leaving a minor gap.

Workflow Clarity

The three numbered steps are clearly sequenced (research against primary sources → write findings with sources → save to the repo's notes location), with a decision checkpoint for the no-convention case. It is not 5 because there is no validation/verification step (e.g., confirming the saved file's path back to the user or re-checking that every claim has a source) after the agent completes; it is well above 3 since the sequence is complete and includes fallback logic rather than having implicit gaps.

Progressive Disclosure

The skill is under 50 lines, single-purpose, and has no bundle files (no references/, scripts/, or assets/ exist, and the body references none), so per the rubric's simple-skill guidance it can score 5 with well-organized content — which it has: a one-line purpose statement followed by an ordered three-item task list, with nothing inlined that belongs in a separate file. Not a 4, as there are no organization gaps or misplaced content.

Specificity

The description names two concrete actions — "对照高可信一手来源调研问题" (research questions against high-trust primary sources) and "把发现保存为仓库中的 Markdown 文件" (save findings as a Markdown file in the repo) — which matches the anchor 'names domain and 1-2 concrete actions, but not comprehensive'. It is not a 4 because it does not enumerate several specific actions (e.g., which kinds of sources or output activities), and not a 2 because the actions given are concrete rather than generic.

Completeness

It explicitly answers both parts: 'what' is "对照高可信一手来源调研问题，并把发现保存为仓库中的 Markdown 文件", and 'when' is an explicit trigger clause "适用于用户想调研主题、收集文档或 API 事实，或把阅读工作委托给后台代理时" with three concrete trigger phrases. This matches the anchor 'clearly and explicitly answers both what AND when with concrete trigger phrases'; a 4 would require the 'when' to be less explicit or specific.

Trigger Term Quality

Natural trigger phrases are present: "调研主题" (research a topic), "收集文档或 API 事实" (collect documentation or API facts), and "把阅读工作委托给后台代理" (delegate reading work to a background agent) — terms a user would plausibly say. It falls short of 5 because common variations/synonyms (e.g., "look this up", "find the docs for", specific format hints) are not covered, but it is well above 3's 'missing common variations' level.

Distinctiveness Conflict Risk

The combination of primary-source verification, repo-saved Markdown output, and background-agent delegation gives it a distinct niche unlikely to fire for unrelated skills. It is not a 5 because 'research' and 'collect documentation' are broad enough to overlap with general research/search skills, but well above 3's 'could still overlap with similar skills'.