# 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

Topic	Page
AI Agent Node Configure LLM reasoning, tools, knowledge sources, and agentic behavior.	/spaces/FSlso1Kjob5CLDrh0dVn/pages/YjEQjSjqwYs4YdqzgwL9
Knowledge Bases Connect document stores and structured data for retrieval-augmented generation.	/spaces/FSlso1Kjob5CLDrh0dVn/pages/IyHE7n42v7FygdPABjeO
StackAI Access StackAI platform features like Human-in-the-Loop from within a workflow.	/spaces/FSlso1Kjob5CLDrh0dVn/pages/786Fqu82gGo3nFSKLvIT

### 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. --- # Agent Instructions: 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: ``` GET https://docs.stackai.com/workflow-builder/core-nodes.md?ask= ``` The question should be specific, self-contained, and written in natural language. 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.