Azure Functions MCP

Initialize a new Azure Functions project using your preferred language stack. For .NET use 'func init --worker-runtime dotnet-isolated', for Python use 'func init --worker-runtime python', for TypeScript use 'func init --worker-runtime node --language typescript'.

func init MyMcpFunctionsApp --worker-runtime dotnet-isolated

For .NET projects, add the Azure Functions MCP NuGet package. For other language stacks, the extension is configured via the host.json file and the extension bundle.

dotnet add package Microsoft.Azure.Functions.Worker.Extensions.Mcp --prerelease

Create a function that uses the McpToolTrigger binding. The trigger attribute defines the tool name and description that will be exposed to MCP clients. Each decorated function becomes a callable tool in your MCP server.

[Function("GetWeather")]
public string GetWeather(
    [McpToolTrigger("get_weather", "Get current weather for a city")] ToolInvocationContext context)
{
    var city = context.Arguments["city"]?.ToString();
    return $"Weather in {city}: Sunny, 72F";
}

Add an 'mcp' section to your host.json to set the server name, version, and system instructions that will be sent to connecting MCP clients.

{
  "version": "2.0",
  "extensions": {
    "mcp": {
      "instructions": "This server provides weather and data tools.",
      "serverName": "MyAzureMcpServer",
      "serverVersion": "1.0.0"
    }
  }
}

Deploy your Functions app to Azure using the Azure CLI or VS Code. Once deployed, the MCP endpoint will be available at your function app's URL. Use the Azure portal or CLI to retrieve the function URL.

func azure functionapp publish <YOUR_FUNCTION_APP_NAME>

Add the deployed Azure Functions MCP server to your MCP client configuration using the SSE or streamable-HTTP transport. Replace the URL with your actual Azure Function app endpoint.