[BUG] --resume doesn't use the model from the original session

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 starting a session with a specific model such as claude --model='claude-opus-4-6[1m]' then later you resume the session using claude --resume <ID> without explicitly passing the model again --model='claude-opus-4-6[1m]', the model used in the resumed session defaults to claude code's default model (Opus 4.7 1M).

What Should Happen?

Since the session was started with a specific model I'd expect resumption to continue using such model.

Error Messages/Logs

Steps to Reproduce

1. Start a session with claude --model='claude-opus-4-6[1m]'
2. Do anything to trigger the model
3. Run /exit
4. Resume the session with claude --resume <ID>
5. Note the model used is not the model the original session started with

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

1.0.126

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_