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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

Claude Code v2.1.304 ·

Fast mode dialog shows "research preview" only some of the time

The Fast mode dialog title now adds "(research preview)" only under a certain condition, instead of always

You'll notice Improvements
JSON All of v2.1.304
You'll noticeTier: how much it should matter to you
1Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
ModelsArea: what it touches
ImprovementsKind: in v2.1.304,
ImprovementsSection of the release

Unclear It is not clear what condition decides whether the "(research preview)" label is shown.

What

The title of the Fast mode dialog used to always read "Fast mode (research preview)". It now adds " (research preview)" only when a particular condition is met. Otherwise the title is just "Fast mode".

Why

The preview label is no longer fixed. Some people will see the Fast mode dialog without the "research preview" wording.

How sure we are
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtIt is not clear what condition decides whether the "(research preview)" label is shown.
Anthropic's release notes agreeRemoved the "(research preview)" label from the /fast dialog title on Opus 5.5

See this entry in the whole of v2.1.304 →

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