> For the complete documentation index, see [llms.txt](https://docs.stackai.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.stackai.com/workflow-builder/core-nodes.md).

# Core Nodes

Core nodes are the primary building blocks of every StackAI workflow — the AI reasoning layer, the knowledge retrieval layer, and the platform utility layer.

These nodes handle the heavy lifting: reasoning over prompts, retrieving context from data, and calling StackAI's platform features.

### In this section

<table data-view="cards"><thead><tr><th>Topic</th><th data-card-target data-type="content-ref">Page</th></tr></thead><tbody><tr><td><strong>AI Agent Node</strong><br>Configure LLM reasoning, tools, knowledge sources, and agentic behavior.</td><td><a href="/spaces/FSlso1Kjob5CLDrh0dVn/pages/YjEQjSjqwYs4YdqzgwL9">/spaces/FSlso1Kjob5CLDrh0dVn/pages/YjEQjSjqwYs4YdqzgwL9</a></td></tr><tr><td><strong>Knowledge Bases</strong><br>Connect document stores and structured data for retrieval-augmented generation.</td><td><a href="/spaces/FSlso1Kjob5CLDrh0dVn/pages/IyHE7n42v7FygdPABjeO">/spaces/FSlso1Kjob5CLDrh0dVn/pages/IyHE7n42v7FygdPABjeO</a></td></tr><tr><td><strong>StackAI</strong><br>Access StackAI platform features like Human-in-the-Loop from within a workflow.</td><td><a href="/spaces/FSlso1Kjob5CLDrh0dVn/pages/786Fqu82gGo3nFSKLvIT">/spaces/FSlso1Kjob5CLDrh0dVn/pages/786Fqu82gGo3nFSKLvIT</a></td></tr></tbody></table>

### Start with the AI Agent Node

* The [**AI Agent Node**](/workflow-builder/core-nodes/ai-agent-node.md) is the core reasoning unit — configure it first.
* Add [**Knowledge Bases**](/workflow-builder/core-nodes/knowledge-bases.md) to give your agent access to documents or data.
* Use [**Human in the Loop**](/workflow-builder/core-nodes/stackai/human-in-the-loop.md) when workflows need human review before proceeding.


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

```
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