[BUG] 1M Opus 4.6 context length doesn't work AWS bedrock

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 (1M context)" when using AWS Bedrock doesn't work

What Should Happen?

It should work. The 1M context length is supported by the bedrock API: https://www.aboutamazon.com/news/aws/anthropic-claude-4-opus-sonnet-amazon-bedrock

Error Messages/Logs

Steps to Reproduce

1. select "Opus (1M context)" in the model picker whilst using AWS bedrock
2. when running a command the following error appears:

API Error (claude-opus-4-6[1m]): 400 The provided model identifier is invalid.

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.38 (Claude Code)

Platform

AWS Bedrock

Operating System

macOS

Terminal/Shell

Other

Additional Information

_No response_