Extend Claude with skills changedskills
Nearest release: v2.1.312, published under an hour before upstream edited the page. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.
Upstream edited this page at 27 Oct 2026 19:25 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 27 Oct 2026 19:37 UTC.
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384384Your skill instructions here...
385385```
386386
387All fields are optional. Only `description` is recommended so Claude knows when to use the skill. A field name must match the table exactly, hyphens included: Claude Code ignores a field it doesn't recognize without reporting an error.
387All fields are optional. Only `description` is recommended so Claude knows when to use the skill. A field name must match the table exactly, hyphens included: Claude Code ignores a field it doesn't recognize without reporting an error. Boolean fields accept `yes`, `no`, `on`, `off`, `1`, and `0` in any letter case, in addition to `true` and `false`.
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389389Claude Code reads the frontmatter only when the opening `---` is the file's first line. Otherwise it treats the whole file, `---` markers included, as skill content. If the YAML between the markers doesn't parse, the skill still loads with no fields set; see [Skill not triggering](#skill-not-triggering) to find and fix the error.
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391Boolean fields accept `yes`, `no`, `on`, `off`, `1`, and `0` in any letter case, in addition to `true` and `false`. Before v2.1.218, Claude Code recognized only `true` and `false`.
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393391| Field | Required | Description |
394392| :- | :- | :- |
395393| `name` | No | Command name shown in the `/` menu. Defaults to the directory name. See [How a skill gets its command name](#how-a-skill-gets-its-command-name) for how the field interacts with the name you type to invoke the skill. |
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405403| `effort` | No | [Effort level](https://code.claude.com/docs/en/model-config.md#adjust-effort-level) when this skill is active. Overrides the session effort level. When you omit it, the level comes from the [effort resolution order](https://code.claude.com/docs/en/model-config.md#adjust-effort-level). Options: `low`, `medium`, `high`, `xhigh`, `max`; available levels depend on the model. |
406404| `context` | No | Set to `fork` to run in a forked subagent context. See [Run skills in a subagent](#run-skills-in-a-subagent). |
407405| `agent` | No | Which subagent type to use when `context: fork` is set. |
408| `background` | No | Only applies with `context: fork`. Set to `false` to wait for the forked subagent's result in the turn that invoked the skill, instead of [running it in the background](#run-skills-in-a-subagent). Default: `true`. Requires Claude Code v2.1.218 or later. |
406| `background` | No | Only applies with `context: fork`. Set to `false` to wait for the forked subagent's result in the turn that invoked the skill, instead of [running it in the background](#run-skills-in-a-subagent). Default: `true`. |
409407| `hooks` | No | Hooks that Claude Code registers when the skill is invoked and keeps running for the rest of the session. See [Hooks in skills and agents](https://code.claude.com/docs/en/hooks.md#hooks-in-skills-and-agents) for the configuration format, the `once` option, and the [limits on skill hooks](https://code.claude.com/docs/en/hooks.md#limits-on-skill-hooks). |
410408| `paths` | No | Glob patterns that limit when this skill is activated. Accepts a comma-separated string or a YAML list. When set, Claude loads the skill automatically only when working with files matching the patterns. Patterns are relative to Claude's current working directory, and files outside that directory don't match. Uses the same glob format as [path-specific rules](https://code.claude.com/docs/en/memory.md#path-specific-rules). |
411409| `shell` | No | Shell to use for `` !`command` `` and ` ```! ` blocks in this skill. Accepts `bash` (default) or `powershell`. Setting `powershell` runs inline shell commands via PowerShell when the [PowerShell tool](https://code.claude.com/docs/en/tools-reference.md#powershell-tool) is enabled: it's on by default on Windows without Git Bash, on by default with Git Bash for claude.ai and Console accounts, and needs `CLAUDE_CODE_USE_POWERSHELL_TOOL=1` in Amazon Bedrock, Google Cloud's Agent Platform, and Microsoft Foundry sessions and on macOS, Linux, and WSL. Set it to `0` to turn the tool off. |
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796794>
797795> Despite the name, a skill with `context: fork` doesn't run in a [fork of the current conversation](https://code.claude.com/docs/en/sub-agents.md#fork-the-current-conversation), which would hand the subagent everything you've discussed so far. When the task depends on that history, fork the conversation instead of using `context: fork`.
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799The forked subagent runs in the [background](https://code.claude.com/docs/en/sub-agents.md#run-subagents-in-foreground-or-background): you keep working while it runs, and its result arrives in your conversation when it completes. Set `background: false` in the frontmatter to instead wait for the result in the turn that invoked the skill. Before v2.1.218, forked skills always blocked the turn until they finished.
797The forked subagent runs in the [background](https://code.claude.com/docs/en/sub-agents.md#run-subagents-in-foreground-or-background): you keep working while it runs, and its result arrives in your conversation when it completes. Set `background: false` in the frontmatter to instead wait for the result in the turn that invoked the skill.
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801799Claude Code also waits for the result, even when the skill doesn't set `background: false`, in cases like these:
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