Using Claude Code? Check your settings
Anthropic announced the end of Opus 4.8 fast mode in the Claude Code 2.1.316 changelog. It has been deprecated since October 30, 2026, and will be removed on November 30. After that, requests will return an error instead of falling back to the standard mode.
Key facts
| Deprecated | October 30, 2026 |
|---|---|
| Removed | November 30, 2026 |
| After removal | Returns an error, no fallback to standard Opus 4.8 |
| Move to | Opus 5.5 |
| Opus 5.5 fast pricing | $8 input, $40 output per 1M tokens |
| Changelog version | Claude Code 2.1.316 |
What happened
Anthropic announced in the Claude Code 2.1.316 changelog that it is ending fast mode for Opus 4.8. It has been deprecated since October 30, 2026, and will be removed on November 30.
Why you should check
This change is not a quiet slowdown. According to the changelog, after removal, fast mode requests for Opus 4.8 will return an error and will not fall back to standard Opus 4.8. Our reading: any job whose settings pin both Opus 4.8 and fast mode may stop working from that day.
Who is affected
- According to the fast mode docs, fast mode works with Opus 5.5, Opus 5 and Opus 4.8. It does not work with Sonnet or Haiku.
- If you don't use Opus 4.8 in fast mode, this change does not affect you.
- In Claude Code 2.1.280 and later, the default fast mode model is already Opus 5.5.
Cost and limits
- Fast mode pricing per 1M tokens is $8 input and $40 output for Opus 5.5. For Opus 5 and Opus 4.8 it is $10 input and $50 output.
- It is available only through the Anthropic API and subscriptions. It is not available on Amazon Bedrock, Google Cloud Agent Platform, Microsoft Foundry or Claude Platform on AWS.
- Subscription plans need usage credits turned on, and on Team and Enterprise an Owner has to turn them on first.
How to check
- In Claude Code, run
/modelto see your current model. - Run
/fastto turn fast mode on or off. - The changelog advises moving to Opus 5.5 to keep the speed.
- To turn it off entirely, set the environment variable
CLAUDE_CODE_DISABLE_FAST_MODE=1. - If you have written model names into automation scripts, it is worth checking them before November 30.
Sources
Questions
When will it be removed?
On November 30, 2026.
What happens after that?
Fast mode requests for Opus 4.8 will return an error. They will not fall back to standard Opus 4.8.
Do I need to do anything if I don't use fast mode?
The changelog entry is about fast mode for Opus 4.8. If you don't use it, it does not apply to you.
