Desktop application changeddesktop
Nearest release: v2.1.284, 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 28 Sep 2026 17:53 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 28 Sep 2026 18:07 UTC.
Upstream edited
Recorded here
Lines+3added
Lines−3removed
From line
641
where the diff opens
First seen
14 Aug 2026
this site's first read of the page
Recorded edits41to this page, all time
The whole hunk
from line 641, old and new numbered
/
from line 641
641641
642642To set environment variables for local sessions and dev servers on any platform, open the environment dropdown in the prompt box, hover over **Local**, and click the gear icon to open the local environment editor. Variables you save here are stored encrypted on your machine and apply to every local session and preview server you start. You can also add variables to the `env` key in your `~/.claude/settings.json` file, though these reach Claude sessions only and not dev servers. See [environment variables](/docs/en/env-vars) for the full list of supported variables.
643643
644[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 environment editor to turn thinking off; this has no effect on Opus 5.5 or the Fable models, which always use extended thinking. With thinking turned off on the Anthropic API, Claude Code sends effort `high` instead of a higher level to models it knows [don't accept that combination](/docs/en/errors#effort-isnt-available-with-thinking-turned-off), such as Opus 5.
644[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 environment editor to turn thinking off; this has no effect on Opus 5.5, Sonnet 5.5, or the Fable models, which always use extended thinking. With thinking turned off on the Anthropic API, Claude Code sends effort `high` instead of a higher level to models it knows [don't accept that combination](/docs/en/errors#effort-isnt-available-with-thinking-turned-off), such as Opus 5.
645645
646On models with [adaptive reasoning](/docs/en/model-config#adjust-effort-level), `MAX_THINKING_TOKENS` values other than `0` are ignored because adaptive reasoning controls thinking depth instead. On Opus 4.6 and Sonnet 4.6, set `CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING` to `1` to use a fixed thinking budget; Fable models, Sonnet 5, and Opus 4.7 and later always use adaptive reasoning and have no fixed-budget mode.
646On models with [adaptive reasoning](/docs/en/model-config#adjust-effort-level), `MAX_THINKING_TOKENS` values other than `0` are ignored because adaptive reasoning controls thinking depth instead. On Opus 4.6 and Sonnet 4.6, set `CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING` to `1` to use a fixed thinking budget; Fable models, Sonnet 5 and later, and Opus 4.7 and later always use adaptive reasoning and have no fixed-budget mode.
647647
648648#### Local sessions on managed devices
649649
No line in this hunk matches that.