MCP App

Go to script.google.com and create a new standalone script project, or open an existing Google Workspace project (linked to a Sheet, Doc, etc.) where you want to add MCP capabilities.

In your Apps Script project, click Libraries (+), search for the MCPApp library by its script ID, select the latest version, and add it to your project.

Create a doPost function that initializes MCPApp with an access key and registers your tools. MCPApp handles all protocol-level routing (initialize, tools/list, tools/call, prompts/list) automatically.

function doPost(e) {
  const mcp = new MCPApp.mcpApp({ accessKey: "your-secret-key" });
  mcp.addTool({
    name: "get_spreadsheet_data",
    description: "Returns data from a Google Sheet",
    inputSchema: { type: "object", properties: { range: { type: "string" } } },
    handler: (args) => SpreadsheetApp.getActiveSheet().getRange(args.range).getValues()
  });
  return mcp.handle(e);
}

Click Deploy → New deployment → Web App. Set 'Execute as' to yourself and 'Who has access' to Anyone (or your organization). Copy the deployment URL.

Add the deployed web app URL to your MCP client configuration. For clients that support HTTP/SSE MCP servers, point them directly at the deployment URL.

{
  "mcpServers": {
    "mcpapp": {
      "url": "https://script.google.com/macros/s/YOUR_DEPLOYMENT_ID/exec"
    }
  }
}

Verify your MCP server responds correctly by sending a tools/list request via curl before connecting a full client.

curl -L "https://script.google.com/macros/s/YOUR_DEPLOYMENT_ID/exec" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}}'