Extend Claude with skills changedskills
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Upstream edited this page at 30 Sep 2026 07:05 UTC, give or take a minute or two: the time comes from Anthropic’s own sitemap rather than from a commit. This site recorded the change at 30 Sep 2026 07:07 UTC.
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859859Seeing a skill trigger tells you Claude found it, not that it did what you intended. To know a skill is working, measure separately whether Claude invokes it on the prompts it should, and whether the output matches what you expect when it does.
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861The check for both is a baseline comparison. Collect a few realistic prompts, run each one in a fresh session with the skill available and again with it [disabled](#override-skill-visibility-from-settings), and compare the results. A fresh session matters because leftover context from authoring the skill will mask gaps in the written instructions.
861The check for both is a baseline comparison. Collect a few realistic prompts, run each one in a fresh session with the skill available and again with it turned off, and compare the results. A fresh session matters because leftover context from authoring the skill will mask gaps in the written instructions.
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863Two tools automate that comparison. For a skill that ships in a [plugin](/docs/en/plugins/overview), [`claude plugin eval`](/docs/en/plugin-evals) runs each prompt in an isolated session with and without the plugin, scores it with graders you define or that it writes for you, and exits non-zero below a threshold so you can gate CI on it. For iterating on a single skill inside a Claude Code conversation, the skill-creator plugin below runs a similar loop with its own `evals/evals.json` format. The two formats aren't interchangeable.
863How you turn the skill off for the second run depends on where it comes from:
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865* **Personal or project skill**: set it to `"off"` in [`skillOverrides`](#override-skill-visibility-from-settings).
866* **Skill that a plugin provides**: `skillOverrides` doesn't apply to plugin skills. Use [`claude plugin eval`](/docs/en/plugin-evals#the-no-plugin-baseline) instead, which repeats each run with no plugin loaded.
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868Two tools automate the baseline comparison. For a skill that ships in a [plugin](/docs/en/plugins/overview), [`claude plugin eval`](/docs/en/plugin-evals) runs each prompt in an isolated session with and without the plugin, scores it with graders you define or that it writes for you, and exits non-zero below a threshold so you can gate CI on it. For iterating on a single skill inside a Claude Code conversation, the skill-creator plugin below runs a similar loop with its own `evals/evals.json` format. The two formats aren't interchangeable.
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865870### Run evals with skill-creator
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