[BUG] linux CLI parameter "--effort max" accepted without error but is not set, model runs at effort=default

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?

Linux CLI, claude code v 2.1.81

Model: claude-opus-4-6

claude --effort max is ignored and behaviour is default.

What Should Happen?

Effort (or reasoning) should be set to 100.

Error Messages/Logs

Steps to Reproduce

claude -p "Print your model and effort level." --model claude-opus-4-6 --effort max

Model: Claude Opus 4.6 (claude-opus-4-6)
Effort level: Not explicitly set (default)

Compare with --effort high

claude -p "Print your model and effort level." --model claude-opus-4-6 --effort high

My model is Claude Opus 4.6 (model ID: claude-opus-4-6).
My reasoning effort level is 99 (out of 100).

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.81 (Claude Code)

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Xterm

Additional Information

_No response_