[BUG] Sonnet 4.6 blocked by forced 1M context mode requiring additional credits on Pro plan

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?

Issue

Sonnet 4.6 has become unusable on my Pro plan due to the 1M extended context feature being forced without opt-out. Every attempt to use Sonnet 4.6 now triggers: "Usage credits required for 1M context"

Context

• Plan: Pro (paid)
• Timeline: Sonnet 4.6 worked without issues 3 days ago (May 21, 2026)
• Current Status: All Sonnet 4.6 sessions blocked by credit requirement as of May 24, 2026
• Environment: Claude Code Desktop

Problem

1. The system appears to force 1M context window on Sonnet 4.6 models
2. This requires additional usage credits beyond the Pro plan
3. No GUI option exists to disable extended context or revert to standard 200K context
4. The extended context feature was not explicitly enabled—it appears to be automatic
5. This creates a situation where Sonnet 4.6 is effectively locked behind an undisclosed credit requirement

Expected Behavior

• Pro plan users should have clear control over context window selection
• Either: Allow standard 200K context without additional credits, OR
• Provide an explicit opt-in/opt-out toggle for extended context mode before consuming credits

Actual Behavior

• Sonnet 4.6 is completely inaccessible on Pro plan
• Forced 1M context mode with no way to disable it
• Requires credits to use a model that should be included in Pro plan

What Should Happen?

• Pro plan users should have clear control over context window selection
• Either: Allow standard 200K context without additional credits, OR
• Provide an explicit opt-in/opt-out toggle for extended context mode before consuming credits
• Sonnet 4.6 should be accessible without requiring additional credits

Error Messages/Logs

Steps to Reproduce

1. Open Claude Code Desktop
2. Ensure you're on a Pro plan account
3. Try to create a new session with Sonnet 4.6 model
4. Observe the message: "Usage credits required for 1M context"
5. Attempt to switch to standard 200K context mode
6. Confirm there is no option to disable 1M extended context

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

May 21, 2026

Claude Code Version

2.1.132 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_