[BUG] "Usage credits required for 1M context" error when context is set to Medium on Sonnet 4.6

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 using the Claude Code desktop app with context set to Medium and model set to Sonnet 4.6, every prompt returns:

"API Error: Usage credits required for 1M context · turn on usage credits at claude.ai/settings/usage, or use --model to switch to standard context"

The Medium context selector should not be triggering the 1M extended context billing gate. Sonnet 4.6 has a 200K standard context window, and Medium context should stay well within that without requiring usage credits.

What Should Happen?

Setting context to Medium with Sonnet 4.6 should use the standard 200K context window and should not trigger the 1M extended context billing gate. Users should be able to run on Medium context without enabling usage credits.

Error Messages/Logs

The app requests the 1M extended context variant regardless of the GUI context selector being set to Medium. The error blocks all prompts until usage credits are enabled or the --model CLI flag is used as a workaround.

Steps to Reproduce

1. Open Claude Code desktop app
2. Set context selector to Medium
3. Set model to claude-sonnet-4-6
4. Submit any prompt
5. Error appears: "Usage credits required for 1M context"

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude Code: Desktop (GUI)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Windows Terminal

Additional Information

• OS: Windows 11
• Claude Code: Desktop (GUI)
• Model: claude-sonnet-4-6
• Context setting: Medium