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28782878**Tool name:** `TodoWrite`
28792879
28802880<Note>
2881 On Python Agent SDK 0.2.139 and later, the following restriction applies.
2881 The following tools are available by default only on Claude 3.x models, Opus 4 through 4.7, Sonnet 4 through 4.6, and Haiku 4.5. On every other model, including model IDs Claude Code doesn't recognize, they aren't available unless you opt in:
28822882
2883 The following tools aren't available on Opus 4.8, Sonnet 5, Fable 5, Mythos 5, or later versions of those families unless you opt in:
2884
28852883 * `TodoWrite`
28862884 * `TaskCreate`
28872885 * `TaskGet`
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28882886 * `TaskUpdate`
28892887 * `TaskList`
28902888
2891 On other models, Claude Code provides the Task tools by default and `TodoWrite` only when you set `CLAUDE_CODE_ENABLE_TASKS=0`.
2889 Wherever the tools are available, Claude Code provides the four Task tools, or `TodoWrite` instead when you set `CLAUDE_CODE_ENABLE_TASKS=0`.
2890
2891 This default set applies in Claude Code v2.1.268 and later, which the TypeScript Agent SDK bundles from v0.3.268.
28922892
28932893 See [Model availability](/docs/en/agent-sdk/todo-tracking#model-availability) to opt in.
28942894</Note>