> For the complete documentation index, see [llms.txt](https://docs.appfarm.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.appfarm.io/library/action-nodes/block.md).
# Block
The Block action node can be used to group a set of action nodes and control their execution.
### Properties
| Property | Description |
| ------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Execution Mode** | There are three options:
Sequential (default): When running in sequential mode, the action nodes behave as they would in any other block node.
Parallel: All action nodes are executed in parallel. Useful when fetching data from multiple third parties. If one of the children fails, the entire block will fail. Any catch exception blocks added as direct children to the block will be ignored in this execution mode.
First to finish: All children are executed in parallel, but the block will finish as soon as the first child is done. Note that all the siblings will still run until finished. Any errors occurring in any of the children will be ignored on block level. Any catch exception blocks added as direct children to the block will be ignored in this execution mode.
|
---
# 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 by asking a question.
Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:
```
GET https://docs.appfarm.io/library/action-nodes/block.md?ask=&goal=
```
`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.
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.