[BUG] Chat: Editor Associations setting not respected for markdown file links in chat

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?

When clicking on markdown file links shared by Claude in the chat interface, VS Code does not respect the chat.editorAssociations setting and opens files with the default markdown editor instead of the configured custom editor.

What Should Happen?

The markdown file should open with the custom editor specified in chat.editorAssociations (markdownForHumans.editor).

Error Messages/Logs

Steps to Reproduce

Install a custom markdown editor extension (e.g., "Markdown For Humans")
Open VS Code Settings (JSON)
Add the following configuration:

{
"chat.editorAssociations": {
"*.md": "markdownForHumans.editor"
}
}
Reload VS Code window
In a Claude Code chat session, ask Claude to reference a markdown file
Click on the markdown file link that Claude shares (e.g., [CLAUDE.md](CLAUDE.md))

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.68 (Claude Code)

Platform

AWS Bedrock

Operating System

macOS

Terminal/Shell

VS Code integrated terminal

Additional Information

The workbench.editorAssociations setting works correctly when opening files from the Explorer
The chat.editorAssociations setting appears to be ignored specifically for links clicked in the Claude Code chat interface
VS Code Version: 1.109.5
Claude Code Extension Version: 2.1.68
OS: macOS (Darwin 25.3.0)

<img width="1119" height="438" alt="Image" src="https://github.com/user-attachments/assets/601f783c-7453-4fa2-a883-f79290eda9fe" />