AI agents
What is an AI agent made of?
Every agent, however it is built, comes down to three parts: a model that does the reasoning, tools that let it act, and instructions that hold the goal and the rules.
Every agent, however it is built, comes down to three parts.
- A model that does the reasoning. This is the brain that decides what to do next.
- Tools that let it act: read a file, run a search, call an API, send a message. Without tools an agent can only talk. With them it can change things. See tool use and MCP.
- Instructions that hold the goal and the rules: what success looks like and what the agent may or may not do.
OpenAI’s guide frames these as the model, the tools, and the instructions that give the agent a reliable plan.[1] Strip out the tools and you are back to a chatbot. Strip out the instructions and the model has nothing to aim at.