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How-to · Tools and permissions

Switch an MCP server on for a session

Turn an MCP server on or off for the session in front of you, without changing what every new session starts with.

You want an MCP server on or off for the session in front of you, without changing what every new session starts with.

1. In the composer's status row, press MCP. It shows a count, such as MCP · 2, once a server is switched on for this session.
2. The popover lists every server configured for every directory, plus any configured specifically for this session's own directory. Each has its own checkbox and its connection status: connected, connecting, failed or needs sign-in.
3. Check or uncheck a server's box. A running session picks up the change on its next turn. A session with nothing running starts with what the switches say.

A Gemini session freezes this menu once its chain has sent its first message. Every switch is disabled, and pointing at a disabled switch names the reason.

See Settings for the General tab's MCP servers field, the app-wide default this menu overrides for a single session.