MCP Server for Google Tasks

A reference implementation of an MCP server for Google Tasks, built with the Go MCP SDK.

The server itself does not perform any authentication. It expects an upstream gateway to authenticate the user and forward a Google OAuth access token (with the Google Tasks scope) in the standard Authorization: Bearer <token> header. The token is passed straight through to the Google Tasks API.

Features

Tools

Tool	Description
search	Search for tasks by title or notes
list	List all tasks across all task lists
create	Create a new task
update	Update an existing task
delete	Delete a task
clear	Clear completed tasks from a task list

Resources

URI Pattern	Description
gtasks:///{taskId}	Read detailed task information

Architecture

MCP Client ──► Auth Gateway ──► MCP Server ──► Google Tasks API
                  (issues          (forwards
                   Google           Bearer
                   access           token)
                   token)

The gateway is responsible for the entire OAuth flow, token storage, and refresh. This server only:

1. Reads the Authorization: Bearer <token> header.
2. Returns 401 Unauthorized if the header is missing.
3. Uses the token as a Google OAuth access token when calling the Tasks API.

If Google rejects the token (expired, wrong scope, etc.), the corresponding tool call fails with the error returned by Google.

Endpoints

Endpoint	Method	Description
/mcp	POST	MCP Streamable HTTP (requires Bearer access token)

Configuration

Variable	Required	Default	Description
PORT	No	8080	HTTP server port

Run

go run .

Docker

docker run --rm -p 8080:8080 \
  ghcr.io/agentic-layer/mcp-server-gtasks:latest

MCP Client Configuration

{
  "mcpServers": {
    "gtasks": {
      "url": "http://localhost:8080/mcp",
      "headers": {
        "Authorization": "Bearer <google-access-token>"
      }
    }
  }
}

In production the gateway injects the Authorization header on behalf of the client.

Getting a Temporary Token for Testing

The token must be a Google OAuth access token with the https://www.googleapis.com/auth/tasks scope. Pick whichever option is most convenient.

Option 1: Google OAuth 2.0 Playground (no setup)

1. Open https://developers.google.com/oauthplayground/.
2. In Step 1, find Tasks API v1 and select https://www.googleapis.com/auth/tasks. Click Authorize APIs and complete the Google sign-in.
3. In Step 2, click Exchange authorization code for tokens.
4. Copy the Access token value. It is valid for ~1 hour.

Option 2: gcloud CLI

Requires a Google Cloud SDK install and a Google account.

gcloud auth application-default login \
  --scopes=https://www.googleapis.com/auth/tasks,openid

gcloud auth application-default print-access-token

The printed token is a short-lived Google access token you can pass to the server.

Smoke test

TOKEN="<paste-token-here>"

# Verify the token has the Tasks scope.
curl -s "https://www.googleapis.com/oauth2/v3/tokeninfo?access_token=$TOKEN"

# Hit the MCP endpoint.
curl -i -X POST http://localhost:8080/mcp \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'