[BUG] Wrong AI model name reported with `ANTHROPIC_MODEL = private in-house inference profile ARN`

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?

1. I set ANTHROPIC_MODEL with our own AWS Bedrock "inference profile" ARN, such like "ANTHROPIC_MODEL": "arn:aws:bedrock:ap-northeast-1:1234567890:application-inference-profile/1234567890abcedf"
2. Then, Claude Code reports wrong AI model name

• e.g. I using Claude Opus 4.5 on AWS Bedrock via the step 1.'s inference profile and also I does not have 4.6 setup on our AWS environment yet, but Claude Code makes Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> header when making Git commit

What Should Happen?

I expect one of these behavior:

• Report correct AI model name (in the Git commit Co-Authored-By etc.)
• Or, just say "model name unknown", "using custom model" or similar

Error Messages/Logs

No visible error messages nor logs

Steps to Reproduce

1. I set ANTHROPIC_MODEL with own in-house/private AWS Bedrock "inference profile" ARN, such like "ANTHROPIC_MODEL": "arn:aws:bedrock:ap-northeast-1:1234567890:application-inference-profile/1234567890abcedf", and also set CLAUDE_CODE_USE_BEDROCK=true
2. Let Claude Code reports AI model name, such as ask it make Git commit
3. It reports wrong model name

• e.g. I using Claude Opus 4.5, but it makes Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> header when making Git commit

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.37 (Claude Code)

Platform

AWS Bedrock

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Note that /model command correctly reports AWS Bedrock inference profile's ARN and Custom model