# My AI client cannot connect to DevHub, or a tool is missing

> Check in order: the session, the MCP server, the permission of your plan, the allowed tools and the saved setup of the client.

**Symptom:** The client says it cannot reach DevHub, or it connects and a tool it should have is not offered.

**Cause:**

One of these, in the order to check:

1. Nobody is signed in. The server is stopped and answers "sign in required".
2. The MCP server is stopped or shows **Error** on the Dashboard.
3. Your Vartari plan does not include the area for agents. Each tool is offered only when your account may use that area over MCP at the level the tool needs. Deleting files, running scripts, starting agents and taking screenshots need the manage level.
4. The tool is switched off in Settings > MCP Server > **Allowed MCP tools**. It then disappears from discovery and is rejected if called directly.
5. The client holds an old address or old files. The installation was written before something changed.

**Solution:**

1. Sign in, then look at the MCP server card on the [Dashboard](/devhub/features/dashboard/index.md). Click **Start MCP** or **Restart** if needed.
2. For a missing tool, open the [Settings](/devhub/features/settings/index.md) section **MCP Server** and check **Allowed MCP tools**. An area your account does not include stays visible but disabled, with the permission it needs.
3. Copy the MCP address again from the Dashboard (**Copy MCP endpoint**) and give it to the client, or open **Harnesses Manage** and use **Update** on the installation so DevHub writes the files again.
4. Run **Test** on the client in **Harnesses List**. The row says when the client last answered.

**Applies from:** 0.8.1

Nothing on your disk is removed because a permission is missing.

## Related

- [MCP server](/devhub/features/mcp-server/index.md)
- [Connect an AI client](/devhub/getting-started/connect-client/index.md)
- [Harnesses](/devhub/features/harnesses/index.md)
- [Errors for agents](/devhub/for-agents/errors/index.md)