What
MCP server config accepts an optional role field marking the server the coordinator uses to talk to the user, and the coordinator's tool filter lets that server's tools through. It is a Claude Code extension to .mcp.json, applied only on your machine, and only takes effect when coordinator mode is on via CLAUDE_CODE_COORDINATOR_MODE.
Evidence
Coordinator mode is activated via the CLAUDE_CODE_COORDINATOR_MODE environment variable; this field only takes effect when coordinator mode is active.
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
Names in the bundle.mcp.jsonCLAUDE_CODE_COORDINATOR_MODE
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Added since
A small documentation edit on Connect to MCP servers touched a line naming .mcp.json after this was published.
* **Cloud sessions**: commit a `.mcp.json` to your repository. See [Edit .mcp.json directly](#edit-mcp-json-directly).mcp-quickstart see the edit
Confirmed since
Anthropic's documentation has since written up .mcp.json, on MCP, plugins, skills, and hooks.
| `.mcp.json` | MCP servers bundled with this plugin. A JSON object keyed by server name: `{"mcpServers": {"<name>": {"type": "http", "url": "...", "oauth": true}}}`. A remote entry uses `type` (`http` or `sse`), not `transport`, and suppo…third-party/claude-desktop/extensions see the edit
Two sources agreeTwo things we can check say the same as this entry.
Anthropic's documentation agrees
Anthropic's documentation has since written up .mcp.json, on MCP, plugins, skills, and hooks.
Anthropic's release notes agree
Fixed /mcp listing a project .mcp.json entry that declares the claude.ai connector type under the trusted "claude.ai" heading; it now…