[BUG] Claude Code can't use HTTP MCP servers with API key authentication

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?

I have an HTTP MCP server that requires Bearer token auth. Works fine with curl and regular VS Code chat, but Claude Code extension it won't send the Authorization header from mcp.json. It just shows the OAuth gate instead of accessing the actual tools. Claude Code needs to actually send these headers.

What Should Happen?

Claude Code should send the custom Authorization header from mcp.json when connecting to the HTTP MCP server, so it can authenticate and access all available tools instead of being blocked by OAuth.

Error Messages/Logs

Steps to Reproduce

Add an HTTP MCP to ~/.config/Code/User/mcp.json that requires Bearer token auth:

{
"servers": {
"test-mcp": {
"type": "http",
"url": "https://your-mcp-endpoint.com/mcp",
"headers": {
"Authorization": "Bearer your-api-key"
}
}
}
}
Open Claude Code and try to use ToolSearch for that MCP

Notice Claude Code only shows OAuth authentication options instead of the actual tools from the server

Verify the server works by running: curl -H "Authorization: Bearer your-api-key" https://your-mcp-endpoint.com/mcp - it returns tools successfully

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Opus 4.8

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_