[BUG] Opus 4.6 at 1m context actually is Opus 4.5
Preflight Checklist
- [x] I have searched existing issues and this hasn't been reported yet
- [x] This is a single bug report (please file separate reports for different bugs)
- [x] I am using the latest version of Claude Code
What's Wrong?
Selecting "Opus 4.6" in Claude Code actually loads claude-opus-4-5-20251101 a completely different, older model.
Users are being served Opus 4.5 while the UI claims it's Opus 4.6. This likely explains the quality degradation and verbose "thinking out loud" behavior users have been reporting, they were never running Opus 4.6 to begin with.
What Should Happen?
Selecting Opus 4.6 should load the actual Opus 4.6 model (claude-opus-4-6).
Users should receive the model they select.
Steps to Reproduce
- Open Claude Code
- Run /model or switch from Sonnet 4.6 to Opus 4.6
- Observe the model string:
claude-opus-4-5-20251101 - Expected
claude-opus-4-6-*and actually gotclaude-opus-4-5-20251101
Claude Model
Opus
Is this a regression?
Yes, this worked in a previous version
Last Working Version
Unknown (Before 1m was forced by default and 400k disappeared)
Claude Code Version
2.1.87
Platform
Anthropic API
Operating System
Windows
Terminal/Shell
VS Code integrated terminal
Additional Information
We have been deceived.
There was a sharp model quality decrease when 1m was forced by the update.
And this is because 4.6 at 1m is actually 4.5.
5 Comments
Found 3 possible duplicate issues:
This issue will be automatically closed as a duplicate in 3 days.
🤖 Generated with Claude Code
I was seeing something similar where Default would select Haiku-4.5-20251001. I reverted the Claude Code for VS Code extension to version 2.1.85 and turned off auto-updates and that solved it for now. FWIW if I used command line native Claude Code, the /model command worked fine and I could change to Opus[1m] no problem. So it may just be a bug with the VS Code extension.
That's what I suspect.
But at the same time the amount of token usage for everyone increased coincidentally when limits got reduced, which is peculiar.
Using Claude through the CLI does appear to be smarter, which may indicate it could be limited to just CC extension, but that's based on my feelings.
<img width="478" height="35" alt="Image" src="https://github.com/user-attachments/assets/53531d64-22e4-40f5-be9d-7d64c96c7518" />
I will close this as it seems the new version fixed it, or at least the model name displayed is the technically correct one.
This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.