Google Tasks: Complete a task — MCP tool

Google Tasks MCP tool: Marks a task completed — the reversible way to finish work.

Technical name: complete_task

What task it solves

I want to mark a task as done.

Sets the task's status to completed; the API stamps the completion time.

When to use it

Whenever work is finished. Prefer this over delete_task for finished work — completion is REVERSIBLE (reopen_task undoes it), deletion is not.

What to provide

• tasklist_id — required. "@default" targets the default list.
• task_id — required. The task id from list_tasks or create_task output.

What it returns

The updated task with status: "completed" and the completed timestamp.

What changes in Google Tasks

The task shows as checked-off in the user's Google Tasks. It stays visible to list_tasks (show_completed defaults to true) until swept by clear_completed_tasks or the UI. Fully reversible via reopen_task.

Example request

Mark "Send the report" as done in Google Tasks.

Errors and limitations

Completing a parent does NOT complete its subtasks — complete each subtask first if the whole tree is done. Completing an already-completed task converges (idempotent). A wrong id returns HTTP 404.

Access also depends on token permissions, quotas, and upstream API limits.

Related MCP tools

• Reopen a task — reopen_task
• Clear completed tasks — clear_completed_tasks
• Delete a task — delete_task

Technical details

• Impact: changes data (reversible via reopen_task)
• Group: Completion
• Description source: complete_task registration in src/tools/completion.ts
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