[BUG] Dictation error: Invalid character in header content ["x-config-keyterms"] on Windows

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?

OS: Windows
Extension version: 2.1.153

What happened:
Clicking the microphone button shows:
"Dictation error: Invalid character in header content ["x-config-keyterms"]"

Steps to reproduce:

1. Open Claude Code panel in VS Code
2. Click the microphone button

What I tried:

• Verified Windows microphone access is enabled
• settings.json has no keyterms settings (tried adding "voiceKeyterms": [])
• Reinstalled the extension
• Cleared cache

What Should Happen?

Clicking the microphone button should start voice dictation without any errors.

Error Messages/Logs

Dictation error: Invalid character in header content ["x-config-keyterms"]

Steps to Reproduce

1. Open VS Code with Claude Code extension (v2.1.153) on Windows
2. Open the Claude Code panel
3. Click the microphone button
4. Error appears immediately: "Dictation error: Invalid character in header content ["x-config-keyterms"]"

Notes:

• Windows microphone access is enabled
• settings.json is empty ({})
• Tried adding "voiceKeyterms": [] to settings.json — did not fix it
• Reinstalled the extension — did not fix it
• Cleared cache — did not fix it

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

claude command not available in terminal; using VS Code extension v2.1.153

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_