Plugin-provided MCP servers do not appear in /mcp panel despite being connected and functional

Description

MCP servers that come from an installed plugin's bundled .mcp.json (as opposed to servers added manually via claude mcp add or a project's own .mcp.json) do not appear in the /mcp interactive panel, even when they are fully connected and their tools work normally.

Steps to reproduce

1. Install a plugin that bundles an MCP server (e.g. context7, or any plugin declaring an mcpServers entry in its manifest).
2. Confirm the server is connected and working via claude mcp list (shows plugin:<plugin>:<server> with a ✔ Connected status), and by successfully calling one of its tools in a session.
3. Run the /mcp slash command inside that same active session.

Expected behavior

/mcp should list all configured MCP servers, including plugin-bundled ones, consistent with what claude mcp list shows.

Actual behavior

/mcp only shows account-linked/managed connectors (e.g. Claude.ai's Gmail/Calendar/Drive integrations). Plugin-provided servers are absent from the panel entirely, even though:

• claude mcp list reports them as ✔ Connected
• Their tools can be called successfully and return real results in the same session
• claude plugin details <plugin-name> confirms the MCP server is declared and active for that plugin

This is purely a display/discovery gap in /mcp — the underlying connection and tool-calling both work correctly. It's confusing in practice because /mcp is the natural place to check server status, and a server's absence there reads as "not connected" when it actually is.

Environment

• Claude Code CLI, latest as of 2026-08-27
• macOS (Darwin)
• Reproduced with an HTTP-transport plugin-provided MCP server; also observed with other plugin-provided servers using different transports

Suggested fix

/mcp should enumerate the same server list claude mcp list uses across all scopes (user, project, local, and plugin-provided), rather than only account-linked connectors.