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whats-new-opus-5-5models/opus-5-5/whats-new-opus-5-5

Every read this site has made of the page, newest first. A date is when upstream edited the page, where upstream publishes that, and otherwise when the poller caught the edit; each row says which of the two it is.

Recorded changes4including the first read

Lines now175in the newest capture

Characters21,800in the newest capture

First seen 23 Sep 2026 18:37 UTC

Last changed 25 Sep 2026 15:37 UTC

Every recorded edit

4 edits since this site first read it

WhenTitle it carriedWhatLines

25 Sep 26 whats-new-opus-5-5 ±changed +1−1 24 Sep 26 whats-new-opus-5-5 ±changed +1−1 24 Sep 26 whats-new-opus-5-5 ±changed +1−1 23 Sep 26 whats-new-opus-5-5 +new page +175−0

As it stands

Lines175
Characters21,800
Categorymodels
Pathmodels/opus-5-5/whats-new-opus-5-5

Read it upstream →

Sections it gained

## New model
## Breaking changes
### Thinking can't be disabled
### Forced tool use is not supported
### Thinking blocks are tied to the model and the conversation
### The `computer_20251124` computer use tool is not supported on the Claude API and Google Cloud
## Feature support
### Fast mode
### Define tools in a message (beta)
### Compact on demand (beta)
## Behavior differences
## Refusals and fallback