Follow Discord
Sweep 22 Oct 2026 · 21:04Z Build v2.1.309 528 read Stable v2.1.308 Latest v2.1.309 Next v2.1.309 Feeds RSS JSON llms.txt llms-full.txt Unofficial
HomeReleasesv2.1.242entry #97

Claude Code v2.1.242 ·

Clearer error when an effort level needs thinking turned on

You now get told when an effort level needs thinking on, and what turned thinking off.

Use it now Improvements
JSON All of v2.1.242
Use it nowTier: how much it should matter to you
3Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
EffortArea: what it touches
ImprovementsKind: in v2.1.242,
What probably matters to youSection of the release
What

A new error branch explains that the effort level you picked is not available with thinking turned off on this model, tells you to raise effort or re-enable thinking, and names what disabled thinking: the MAX_THINKING_TOKENS environment variable, the alwaysThinkingEnabled setting, or the way the session was started.

Details
  • Triggered by the shape of the API error, so it applies wherever the request is made from.
Evidence

isn't available with thinking turned off on this model

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Read from
Names in the bundleMAX_THINKING_TOKENSalwaysThinkingEnabled
Since it was published

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.

Confirmed since Anthropic's documentation has since written up alwaysThinkingEnabled, on Model configuration. | Set the global default | Run `/config` and toggle thinking mode. Saved as `alwaysThinkingEnabled` in `~/.claude/settings.json` | model-config see the edit
Confirmed since Anthropic's documentation has since written up MAX_THINKING_TOKENS, on Environment variables. | `CLAUDE_CODE_DISABLE_THINKING` | Set to `1` to omit the `thinking` parameter from API requests entirely. This is a compatibility option for proxies and gateways that reject the parameter. On models that think by default, omitting the par… env-vars see the edit
Added since A small documentation edit on Desktop application touched a line naming MAX_THINKING_TOKENS after this was published. [Extended thinking](/docs/en/model-config#extended-thinking) is enabled by default, which improves performance on complex reasoning tasks but uses additional tokens. On the Anthropic API, set `MAX_THINKING_TOKENS` to `0` in the local envir… desktop see the edit
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agreesA small documentation edit on Desktop application touched a line naming MAX_THINKING_TOKENS after this was published.

See this entry in the whole of v2.1.242 →

Feedback