Create custom subagents changedsub-agents
Nearest release: v2.1.292, published 11 hours 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 7 Oct 2026 04:25 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 7 Oct 2026 04:37 UTC.
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297297| Field | Required | Description |
298298| :- | :- | :- |
299| `name` | Yes | Unique identifier, such as `code-reviewer` or `reviewer-v2`. [Hooks](/docs/en/hooks#subagentstart) receive this value as `agent_type`. The filename doesn't have to match. Names can't contain `:`, which is reserved for [plugin-scoped identifiers](/docs/en/plugins/overview) such as `my-plugin:reviewer`. Claude Code doesn't load a file whose name contains one and logs an error to the debug log. Before v2.1.218, such names were accepted |
299| `name` | Yes | Unique identifier of at most 256 characters, such as `code-reviewer` or `reviewer-v2`. [Hooks](/docs/en/hooks#subagentstart) receive this value as `agent_type`. The filename doesn't have to match. Names can't contain `:`, which is reserved for [plugin-scoped identifiers](/docs/en/plugins/overview) such as `my-plugin:reviewer` |
300300| `description` | Yes | When Claude should delegate to this subagent |
301301| `tools` | No | [Tools](#available-tools) the subagent can use, as a comma-separated string such as `Read, Grep, Bash` or a YAML list. Inherits every tool available to subagents if omitted. If no entry in the list resolves to a tool, the subagent usually [fails to launch](/docs/en/errors#agent-would-be-spawned-with-zero-tools) with an error naming the entries. To preload Skills into context, use the `skills` field rather than listing `Skill` here |
302302| `disallowedTools` | No | Tools to deny, removed from inherited or specified list. Same format as `tools`. An entry with a specifier, such as `Bash(git push *)`, still [removes the whole tool](#available-tools) |
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333333* **No `name`**: Claude Code treats the file as documentation kept beside your agents.
334334* **An opening `---` that isn't the file's first line**: Claude Code reads the file as having no frontmatter and treats it as documentation.
335* **A `name` that starts with `-` or contains `:`**: Claude Code skips the file and writes an error to the debug log. See the `name` row in the table above.
335* **A `name` that starts with `-`, contains `:`, or is longer than 256 characters**: Claude Code skips the file and writes an error to the debug log.
336336* **A `name` but no `description`**: Claude Code skips the file and writes the reason to the debug log.
337337* **YAML that doesn't parse**: Claude Code reads no fields from the file, skips it, and writes the parse error to the debug log.
338338
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