Part of the AI Engineering track · course 1 of 4
Building AI Agents with the Claude API
An agent is a model in a loop with tools. This course builds the mental model from the ground up: the think-act-observe loop, how tool use actually works over the wire, and how to get reliable structured data back. Challenges simulate the loop in plain JavaScript — no API key required.
3 lessons · ~1.5 hours
Try the first lesson free, no account needed
The agent loop. The rest of the course unlocks with a free account.
1. The Agent Loop
The agent loop
An agent is just a model in a loop — think, act, observe, repeat — until the task is done.
Tool use
Tools are functions you describe to the model with a JSON schema, then dispatch by name when it asks.
Structured output
Force the model to return data your code can trust by treating a tool call as the output schema.