What
A new check decides per model whether the todo tools are offered. For opus 4/8, sonnet 5, fable 5 and mythos 5 they are off unless CLAUDE_CODE_ENABLE_TODO_TOOLS=true or the tengu_rosy_wren gate is on; the gate falls back to off when the server has no value. Any other or unknown model keeps them on.
Details
- The same check now also guards the todo reminder attachment and the deferred todo tool, so those follow the tools.
Evidence
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
Names in the bundleCLAUDE_CODE_ENABLE_TODO_TOOLS
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Added since
A small documentation edit on Environment variables touched a line naming CLAUDE_CODE_ENABLE_TODO_TOOLS after this was published.
| `CLAUDE_CODE_ENABLE_TODO_TOOLS` | Set to `1` to get the task-tracking tools on every model. Without it, Claude Code provides them by default only on the models listed under [Task tool availability](/docs/en/tools-reference#task-tool-avai…env-vars see the edit
Confirmed since
Anthropic's documentation has since written up CLAUDE_CODE_ENABLE_TODO_TOOLS, on Claude Code changelog.
* Changed the task-tracking tools (TaskCreate/Get/Update/List, TodoWrite) to be offered only on Claude 3.x, Opus 4.0–4.7, Sonnet 4.0–4.6, Haiku 4.5; set `CLAUDE_CODE_ENABLE_TODO_TOOLS=1` elsewherechangelog see the edit
Two sources agreeTwo things we can check say the same as this entry.
Anthropic's documentation agrees
Anthropic's documentation has since written up CLAUDE_CODE_ENABLE_TODO_TOOLS, on Claude Code changelog.
Anthropic's release notes agree
Todo/task-tracking tools (TaskCreate/Get/Update/List, TodoWrite) are no longer available on Opus 4.8, Sonnet 5, Fable 5, Mythos 5, and newer…
The name it cites is new in this build
New in this build: CLAUDE_CODE_ENABLE_TODO_TOOLS