[BUG] slash comands conflits with MAX_THINKING_TOKENS environment

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?

After I set MAX_THINKING_TOKENS at ~/.claude/settings.json.

Then I run slash command which set model to claude-3-5-haiku-latest

Will cause api request failed:

<img width="1465" height="613" alt="Image" src="https://github.com/user-attachments/assets/0f429b55-7ae9-4b2d-8c37-1a1d49465d0c" />

What Should Happen?

No error

Error Messages/Logs

⎿ API Error: 400 
    {"type":"error","error":{"type":"invalid_request_error","message":"`max_tokens` must
     be greater than `thinking.budget_tokens`. Please consult our documentation at 
    https://docs.anthropic.com/en/docs/build-with-claude/extended-thinking#max-tokens-an
    d-context-window-size"},"request_id":"req_011CT9vqErxMHDVi1AGMRNJd"}

Steps to Reproduce

1. set "MAX_THINKING_TOKENS": "32000" to ~/.claude/settings.json
2. create a slash command and set model to claude-3-5-haiku-latest
3. run the slash command

Claude Model

Other

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

1.0.113

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Cursor

Additional Information

_No response_