[BUG] Plugin resources aren't automatically added to context window (requires manual `readMcpResource` call)

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?

Given an MCP server with a Resource with uri "org://docs":

If the MCP server is installed via Plugin, referencing "@plugin:myplugin:mymcp:org://docs" in a prompt doesnt automatically load the resource into the context window, requiring Claude to (sometimes unreliably) read the resource via readMcpResource manually.

When the same MCP server is installed via .mcp.json, referencing the resource via "@mymcp:org://docs" works just fine.

What Should Happen?

It's expected that plugin-installed MCP servers are able to be referenced the same as MCP servers installed via .mcp.json.

Error Messages/Logs

Steps to Reproduce

See above

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.0.27

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_