# Request Cancel for an Activity

> For the complete documentation index, see [llms.txt](https://docs.temporal.io/llms.txt).
> Any documentation page is available as raw Markdown by appending `.md` to its URL.

> Ask an Activity Execution to close gracefully so your code can clean up, and what to expect when an attempt is already running.

Request Cancel asks an Activity Execution to close gracefully, giving your code a chance to clean up.

## When to Request Cancel

- A [Standalone Activity](/standalone-activity) is no longer needed, and you want it to stop at a safe point rather
  than be killed mid-attempt.
- A job was submitted in error, and you want the Activity to release the resources it has already acquired.

A [Workflow Activity](/workflow-activity) can't be canceled directly. It receives a cancellation request when its
Workflow is canceled, and from that point behaves the same way a Standalone Activity does.

## What happens when you Request Cancel an Activity

The Activity Execution transitions to `CancelRequested`.

- **If no attempt is running,** the execution closes immediately. This doesn't depend on the Activity Heartbeating.
- **If an attempt is running,** the request reaches your code through the Activity's
  [Heartbeat](/encyclopedia/detecting-activity-failures#activity-heartbeat). A Cancellation error is raised when the
  next Heartbeat response is received, and the Activity transitions to canceled status if your code lets that error
  propagate.
- **If the Activity doesn't Heartbeat,** it isn't interrupted mid-attempt. The request takes effect at the next attempt
  boundary, for example when the
  [Start-To-Close Timeout](/encyclopedia/detecting-activity-failures#start-to-close-timeout) elapses.

See [Cancellation](/activity-execution#cancellation) for how your Activity code accepts or ignores a Cancellation.

## CLI usage

```bash
temporal activity cancel \
  --activity-id my-activity \
  --reason "No longer needed"
```

See the [CLI reference for `temporal activity cancel`](/cli/command-reference/activity#cancel) for all options.

## Important considerations

- **A successful response means the request was accepted, not that the Activity stopped.** Your code may complete or
  fail non-retryably instead of honoring the request.
- **Cancellation can be requested only once.** Repeating the request doesn't deliver a second Cancellation.
- **Request Cancel takes precedence** over Reset and Pause. See [Successive operations](/activity-operations#successive-operations).