<p>Used by workers to tell the service that the <a>ActivityTask</a> identified by the <code>taskToken</code> was successfully canceled. Additional <code>details</code> can be provided using the <code>details</code> argument.</p> <p>These <code>details</code> (if provided) appear in the <code>ActivityTaskCanceled</code> event added to the workflow history.</p> <important> <p>Only use this operation if the <code>canceled</code> flag of a <a>RecordActivityTaskHeartbeat</a> request returns <code>true</code> and if the activity can be safely undone or abandoned.</p> </important> <p>A task is considered open from the time that it is scheduled until it is closed. Therefore a task is reported as open while a worker is processing it. A task is closed after it has been specified in a call to <a>RespondActivityTaskCompleted</a>, RespondActivityTaskCanceled, <a>RespondActivityTaskFailed</a>, or the task has <a href="https://docs.aws.amazon.com/amazonswf/latest/developerguide/swf-dg-basic.html#swf-dev-timeout-types">timed out</a>.</p> <p> <b>Access Control</b> </p> <p>You can use IAM policies to control this action's access to Amazon SWF resources as follows:</p> <ul> <li> <p>Use a <code>Resource</code> element with the domain name to limit the action to only specified domains.</p> </li> <li> <p>Use an <code>Action</code> element to allow or deny permission to call this action.</p> </li> <li> <p>You cannot use an IAM policy to constrain this action's parameters.</p> </li> </ul> <p>If the caller doesn't have sufficient permissions to invoke the action, or the parameter values fall outside the specified constraints, the action fails. The associated event attribute's <code>cause</code> parameter is set to <code>OPERATION_NOT_PERMITTED</code>. For details and example IAM policies, see <a href="https://docs.aws.amazon.com/amazonswf/latest/developerguide/swf-dev-iam.html">Using IAM to Manage Access to Amazon SWF Workflows</a> in the <i>Amazon SWF Developer Guide</i>.</p>

{
  "success": true,
  "data": {
    "id": "abc123",
    "created_at": "2025-01-01T00:00:00Z"
  }
}

{
  "success": false,
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "Invalid request parameters"
  }
}