# MCP server

> Start, stop and restart the DevHub MCP server, copy its address for your AI client and see who is connected.

The MCP server is how an AI client reaches DevHub. While it runs, a connected client can call DevHub's tools: search a vault, read a repository index, use plans. While it is stopped, agents cannot reach DevHub.

## When to use it

- Your client says it cannot reach DevHub.
- You want to stop all agent access for a while.
- You connect a new client and need the MCP address.

## Start, stop or restart

The MCP server card is on the [Dashboard](/devhub/features/dashboard/index.md).

1. Read the status: **Running**, **Stopped** or **Error**. While it runs, the card also shows how long.
2. Click **Stop MCP** to stop it, or **Start MCP** to start it. **Restart** stops it and starts it again. The tray menu has **Stop MCP server** too.
3. If the status is **Error**, DevHub says "Could not start. Check the port in Settings, then start it again." Fix the setting and start it again.

The uptime counts from the moment the server started. Stopping it, or signing out, clears it, and a restart begins at zero.

## Copy the address

The MCP address is not printed in these pages. Copy it from the Dashboard: the MCP server card has a **Copy MCP endpoint** button, and the top bar shows the same address. Paste it into the settings of your AI client, or use **Set up a folder** on **Harnesses Manage** to let DevHub write the client configuration for you. See [Connect an AI client](/devhub/getting-started/connect-client/index.md).

## Choose which tools agents get

Settings > MCP Server has **Allowed MCP tools**. A disabled tool disappears from discovery and is rejected if a client calls it directly. The Dashboard shows how many are enabled, as "N of M tools on", and marks a group amber when part of it is disabled. The tools are listed in the [catalog of DevHub tools](/devhub/reference/mcp-tools/index.md).

## Sign-in and permissions

The server runs only while your session is active and your account may use it. When a session ends, the server stops serving at once and answers every request with "sign in required" until you sign in again. Since 0.8.1 each tool is also offered only when your Vartari plan allows that area for agents, at the level the tool needs. Deleting files, running scripts, starting agents and taking screenshots need the manage level. An area your account does not include stays visible but disabled, with the permission it needs.

## Who is connected

The Dashboard lists **Connected clients** seen in the last 24 hours, active now or idle. The **Activity** screen lists every call: who asked, the tool, the result and how long it took.

> **Note:** Agents reach only the folders and vaults you exposed. See [Organizations and
> projects](/devhub/features/organizations-projects/index.md) and [Vaults](/devhub/features/vaults/index.md).

## Related

- [Dashboard](/devhub/features/dashboard/index.md)
- [Connect an AI client](/devhub/getting-started/connect-client/index.md)
- [Catalog of DevHub tools](/devhub/reference/mcp-tools/index.md)
- [Agents cannot reach DevHub after I signed out, or the MCP server is off](/devhub/troubleshooting/mcp-stopped-after-sign-out/index.md)
- [My AI client cannot connect to DevHub, or a tool is missing](/devhub/troubleshooting/agent-cannot-connect/index.md)