[BUG]

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?

when i try to run a simple bioinformatics analysis using Claude Code Opus-4.8, got error:
● API Error: Claude Code is unable to respond to this request, which appears to violate our Usage Policy (https://www.anthropic.com/legal/aup). Please double press esc to edit
your last message or start a new session for Claude Code to assist with a different task.

but Sonnet 5 works.

More information:
`Session ID: 6aa19aa8-5c85-4cec-8ea7-50c1527270ce

Error type: isApiErrorMessage: true, model field null (not a normal model response)

CLI versions: 2.1.202 (1st attempt) and 2.1.211 (2nd attempt) — reproduced across two versions

Model: claude-opus-4-8 (Opus 4.8, 1M context), effort "ultracode"

Platform: Linux 6.17.0-35-generic`

What Should Happen?

Claude should analyze the project normally

Error Messages/Logs

● API Error: Claude Code is unable to respond to this request, which appears to violate our Usage Policy (https://www.anthropic.com/legal/aup). Please double press esc to edit
  your last message or start a new session for Claude Code to assist with a different task.

Steps to Reproduce

just enter 'Hi' to Claude Code when Opus-4.8 is set, above error message is reproduced

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.211

Platform

Anthropic API

Operating System

Other Linux

Terminal/Shell

Other

Additional Information

_No response_