Issues related to AI Agents

dotnet dnx is not a valid command

The getting started for Claude, Codex, and Copilot CLI uses dotnet dnx, which requires the .NET 10 SDK or newer. On older SDKs, dotnet dnx reports a "command not found" error.

If you want to use the App MCP with an older SDK, install the Dev Server as a global tool and replace dotnet dnx -y uno.devserver with uno-devserver in the commands and config files:

dotnet tool install -g uno.devserver

The App MCP does not appear in Visual Studio

  1. Open the .vs/mcp.json file in Visual Studio. It is located in your solution's root directory.

  2. Verify that the Uno MCP server entry is present:

    "uno": {
  "url": "https://mcp.platform.uno/v1"
}

  3. If the entry is missing, add it to the .vs/mcp.json file and restart Visual Studio.

  4. If the entry exists but the server shows as disconnected, click on "Reconnect" in the file editor:

Visual Studio MCP reconnect in mcp.json

The Uno App MCP should now appear in the list of MCPs in Visual Studio.

The App MCP turns red in Visual Studio 2022/2026

In Visual Studio, the App MCP might turn red on some occasions. To fix this issue, click on the three dots on the right and select Reload.

The uno-app MCP failed to start

The Uno Platform App MCP may fail to start in Claude/Codex/Copilot CLI when it is started in a folder that does not contain an Uno Platform project.

To fix this issue, change directories to a folder that contains the .sln or .slnx file of your project.

Diagnosing Dev Server issues

Tip

When the App MCP fails to start, run uno-devserver disco from your solution directory. Check that hostPath is resolved and that there are no errors. Pass --json for machine-readable output. See Diagnostics (disco) for a full guide.