[BUG] Pro plan — 1M context error blocks all requests

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?

1M context error blocks all requests
Every request 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
Using /model to switch to another model has no effect — the 1M context tier is still used regardless.

What Should Happen?

Token consumption should be proportional to actual message content
/model switch should effectively bypass the 1M context tier
Pro plan should not silently route requests to a paid tier
Usage credit compensation for all 5-hour windows lost since the bug appeared (~2 days ago) until resolution, as every window is effectively unusable on Pro plan

Error Messages/Logs

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

Steps to Reproduce

Open Claude Code Desktop on Windows
Select model claude-opus-4-8
Send 2 normal messages
Observe entire 5h quota consumed
All subsequent requests return the 1M context error
Try /model to switch model → error persists

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Version 1.9659.2 (390d6c)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_