Speed up responses with fast mode changedfast-mode
Nearest release: v2.1.312, 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 27 Oct 2026 19:25 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 27 Oct 2026 19:37 UTC.
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4141* A small `↯` icon appears next to the prompt while fast mode is active
4242* Run `/fast` again at any time to check whether fast mode is on or off
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44Opus 5.5 is the fast mode default in Claude Code v2.1.280 and later. Before v2.1.280, fast mode defaulted to Opus 5 from v2.1.219, and to Opus 4.8 on v2.1.154 through v2.1.218.
44Opus 5.5 is the fast mode default in Claude Code v2.1.280 and later. Before v2.1.280, fast mode defaulted to Opus 5 from v2.1.219.
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4646When you disable fast mode with `/fast` again, you remain on Opus. To switch to a different model, use `/model`.
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