> ## Documentation Index
> Fetch the complete documentation index at: https://docs.phinite.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Node types

> Understand each node type used to compose Agent Graphs.

## Nodes overview

<Frame>
  <img src="https://mintcdn.com/phinite/tvoxV3xiH3k6MtM0/images/blocks.png?fit=max&auto=format&n=tvoxV3xiH3k6MtM0&q=85&s=3ba09db8135657b1c97813c4adb3253b" alt="Node types palette" width="1575" height="988" data-path="images/blocks.png" />
</Frame>

* **Start**: graph entry; one source handle to begin execution
* **Master Agent**: core reasoning unit with prompt, tools, RAG, and variables
* **Child Agent**: reusable/embedded agent with its own variables and prompt
* **Tool**: external API/tool call node
* **Sub-Agent Graph**: reference and invoke another Agent Graph (optional)
* **End**: terminal node for completion