A working definition
Anthropic, which makes Claude, draws a useful line between two kinds of AI system. In a workflow, a developer decides the steps in advance and the model fills in each one. In an agent, the model "dynamically directs its own processes and tool usage", choosing what to do next based on what it just saw. Anthropic also notes that, under the hood, agents are often simple: a model using tools based on feedback from its environment, in a loop.
So when people say "AI agent" they usually mean three things together: a capable language model, a set of tools it can use, and the freedom to decide the order and number of steps.
How does an AI agent work?
- You give it a goal, in plain words: "Make invoices for last week’s unbilled hours and send me the PDFs."
- It plans a first step, for example opening the spreadsheet.
- It acts with a tool: reads a file, runs a search, calls an app, or clicks in a window.
- It looks at the result: the rows it found, an error, a new screen.
- It decides the next step and repeats, adjusting when something unexpected happens.
- It stops when the goal is met, or pauses to ask you when it hits a decision or a permission it doesn’t have.
The "tools" are what make an agent useful. A model with only a chat box can describe how to do a task; a model with tools can do it.
What kinds of AI agents are there?
| Kind | What its tools reach | Typical use |
|---|---|---|
| Coding agents | Files, a terminal, a code editor | Writing and fixing software |
| Browser agents | A web browser, often in the cloud | Booking, shopping, filling web forms |
| Computer-use agents | The screen, mouse and keyboard of a computer | Work in desktop apps with no other way in |
| App-connected agents | Accounts like email, calendar, CRM | Inbox triage, scheduling, updating records |
Many products mix these. The coding agents in particular have become general-purpose: give one a folder and tools and it can do far more than code.
What are AI agents good at today?
- Repetitive multi-step chores with a clear finish line: move data from A to B, produce a document, file it.
- Research and reading: searching, cross-checking and summarising with sources.
- Work across several apps where no integration exists.
- Things you can check quickly: an agent that saves you an hour and needs two minutes of review is a good trade.
