The Building Blocks of AI 🤖 | Tools Agents Use to Think & Act

AI agents are built from a few core building blocks: a language model brain, tools to take actions, memory, and instructions that guide behaviour.

The Four Building Blocks

  • Brain (LLM): does the thinking and reasoning.
  • Tools: let it act — search, calculate, send messages.
  • Memory: remembers earlier steps and facts.
  • Instructions: the rules and goals you set.

Put these four together and you have a working agent. Understanding the blocks makes it easy to see how any agent works.

Frequently Asked Questions

What are the building blocks of an AI agent?

A language model brain (thinking), tools (acting), memory (remembering), and instructions (rules and goals).

Which block does the thinking?

The language model (LLM) brain reasons through the task and decides what to do.

Why is understanding the blocks useful?

Once you know the four parts, you can understand how almost any AI agent works under the hood.