> For the complete documentation index, see [llms.txt](https://docs.irs.systems/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.irs.systems/ltt/documentation/ltt-gui-manual/teststand/customsteptypes/checkstop.md).

# Check Stop

In your testplan you can place a **LTT Check Stop** check wherever you want. It checks if there is a stop request from the user interface, initiated by the user pressing F1 or F8. If this is the case, the step will **jump to the cleanup section** of the currently executing TestStand sequence.

![Check Stop](/files/ET4QAqHfCnkr58FtXVmv)

A **check for stop** is necessary to react to **user stop requests** and **TCC value changes**. By default, the only check for stop is done in [MainSequence](/ltt/documentation/ltt-gui-manual/teststand/processmodel/orderofexecution.md). This means:

* The test execution will only stop after an operation mode sequence returns, which can take a long time or not happen at all.
* The testplan can only react to a [TCC value change](/ltt/documentation/ltt-gui-manual/teststand/operationmodes.md) when the current operation mode is finished.

Both may or may not be desired behavior.

{% hint style="info" %}
Be aware that **LTT Check Stop** only jumps to cleanup of the current sequence. If you are in some nested sequence you will need to place a **LTT Check Stop** in each sequence all way up to your [operation mode sequence](/ltt/documentation/ltt-gui-manual/teststand/operationmodes.md) entry point.
{% endhint %}

***

* [Read more about other stop criteria](/ltt/documentation/ltt-gui-manual/teststand/processmodel/orderofexecution.md#STOP_CONDITIONS)
* [Read more about station control](/ltt/documentation/ltt-gui-manual/lttgui/stationcontrol.md)


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.irs.systems/ltt/documentation/ltt-gui-manual/teststand/customsteptypes/checkstop.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.