[BUG] Code blocks rendered as inline code without syntax highlighting in VSCode extension

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?

In the VSCode extension, code blocks (enclosed with triple backticks ```) are rendered as inline code spans without syntax highlighting. All code appears in a single monochrome color, making it difficult to read and understand.

What Should Happen?

Code blocks should be displayed with:

• Proper syntax highlighting based on the specified language
• Color-coded keywords, strings, variables, comments, etc.
• Visual distinction from inline code
• Respect for VSCode's color theme settings

Error Messages/Logs

None

Steps to Reproduce

1. Open Claude Code in VSCode
2. Ask Claude to provide a code example
3. Observe that the code block appears without syntax highlighting
4. All code text appears in a single color

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.46 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Screenshots

<img width="439" height="449" alt="Image" src="https://github.com/user-attachments/assets/3c5526cf-2eb7-48cf-a0f0-d565b2acdd0a" />

In the screenshot above:

• The code includes language tags (// C language, # Python, # Bash)
• Doxygen comments (@brief, @param, @return) are present
• However, all text appears in the same color without syntax highlighting