AI Agent Building Blocks

These building blocks describe how an agent plans, uses tools, checks results, and stays within constraints.

Tool Calling

Tool calling is when an AI model decides to invoke an external function or API (a tool) to fetch data or perform an action during a task.

Planner

A planner breaks a goal into an ordered set of steps, sometimes delegating subtasks to specialized tools or modules.

Retrieval

Retrieval is the process of selecting relevant documents or facts (often from a vector database or search index) to provide context before generation.

Guardrails

Guardrails are constraints and checks that limit what an agent can do, such as tool permissions, content filters, or required validation steps.