Last updated: April 5, 2026 · Core Concepts · by Daniel Ashford
What is AI Agent?
An LLM that can autonomously plan, use tools, and take actions to complete complex tasks.
Definition
An AI agent is a system built around a language model that can autonomously plan actions, use external tools, make decisions, and iterate to accomplish complex goals. Unlike a simple chatbot, an agent breaks down complex tasks into subtasks.
How It Works
Agents combine LLM reasoning with tool use, memory, and planning. Examples include coding agents that write, test, and debug code autonomously, and research agents that search, synthesize, and produce reports. Agent performance is measured by SWE-bench and Terminal-Bench.
Example
A coding agent given "Fix the login bug": (1) reads error logs, (2) identifies relevant files, (3) writes a fix, (4) runs tests, (5) iterates if tests fail, (6) creates a pull request when passing.
Related Terms
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