[BUG] In Claude Code: Context mismatch between /context and UI chat box

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?

The chat window on the VSCode extension starts to show 100% token usage when actual usage is around 50%. See attached screenshots.

I found mentions in other bugs about overestimating token usage percentage, but nothing mentioning it happening in the VScode extension for Claude.

From the chat:
Based on the /context output, you're using:
Claude Sonnet 4.5 (model ID: claude-sonnet-4-5-20250929)
This is the September 29, 2025 release of Sonnet 4.5.

What Should Happen?

Chat window percentage reporting should accurately reflect current token percentage used.

Error Messages/Logs

Steps to Reproduce

Use extension for a while and then observe the percentage at 100%. Compare with /context reported token usage.

<img width="973" height="458" alt="Image" src="https://github.com/user-attachments/assets/9fd794f7-70c1-46d3-9389-7db076706cf8" />
<img width="945" height="441" alt="Image" src="https://github.com/user-attachments/assets/87c95e83-11ec-4d6b-8650-77add0d23bee" />

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude Sonnet 4.5 (model ID: claude-sonnet-4-5-20250929)

Platform

Other

Operating System

macOS

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_