I am trying to run the VS Code debugger for the first time for my .NET 9 web api. When I hit F5 it doesn’t start debugging and I get this message:

You don’t have an extension for debugging XML. Should we find a XML extension in the Marketplace?

So to fix this issue, I asked Github Copilot what to do to make it work. This was it’s response.

Step-by-step solution:

1. Install the official C# extension (if not already done).
2. Avoid focusing on your .csproj file when starting debugging—open one of your C# source files.
3. Create a launch configuration file to explicitly start debugging your web API.

And this was the launch.json file it created.

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": ".NET Launch Web API",
      "type": "coreclr",
      "request": "launch",
      "preLaunchTask": "build",
      "program": "${workspaceFolder}/dotnetapivue3.Server/bin/Debug/net9.0/dotnetapivue3.Server.dll",
      "args": [],
      "cwd": "${workspaceFolder}/dotnetapivue3.Server",
      "stopAtEntry": false,
      "serverReadyAction": {
        "action": "openExternally",
        "pattern": "\\bNow listening on:\\s+(https?://\\S+)"
      },
      "env": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    }
  ]
}

I added the file to my project then, opened a controller file. Launched the debugger. After that, the project loaded as expected and I was able to set break points for debugging.