What is an AI agent

Last updated: 20 September 2026

An AI agent is software that acts on your behalf. You give it a goal, and instead of answering you it goes and does the work — reads files, runs commands, calls APIs, opens web pages — then looks at what happened and decides the next move.

A chatbot can describe a fix beautifully, but it stops at the description. Asked to change a config file, it tells you what to change; you copy, paste, save, restart. An agent changes it and tells you it's done.

The difference is a loop

A single exchange looks like this:

your question → model → answer → done

An agent looks like this:

your goal → model picks a step → execute → read result → model picks next step → …
                                                                    ↓
                                                         goal reached / stuck

That "read result" is the whole trick. When an agent's instruction runs, it produces real feedback — a command fails, a file isn't there, a page returns 404. That feedback goes back to the model and shapes the next instruction. Which is why it can correct itself: wrong path, try another; request timed out, retry.

This loop is what people mean by tool calling. The model isn't restricted to conversation; it has a set of functions, and each one maps to a real action.

A concrete example

Take "upgrade this project's dependencies to the latest versions":

StepChatbotAgent
LookTells you to run npm outdatedRuns it, sees 12 packages behind
EditHands you a package.json snippetEdits the file, installs
Handle errorsYou paste the error back, it revisesSees the conflict, rolls one package back, retries
VerifyReminds you to run the testsRuns them, two fail, goes back and fixes

The gap isn't intelligence. It's whether the thing has hands. Same underlying model, one talks and one acts.

It gets things wrong, by design

Agents fail differently from chatbots. When a chatbot is wrong, you notice while reading. When an agent is wrong, a file is actually deleted, a branch is actually pushed, an API call actually went out.

Three patterns cover most of it:

This is why every serious agent tool ships some kind of stop-and-ask mechanism. Approval gates, sandboxes, plan mode — different names, same purpose: let a human look before an action that can't be undone.

Why this appeared now

The idea is old; earlier attempts existed. Two things had to land together for it to work: models that reliably emit structured instructions, and context windows large enough to hold a whole task's back-and-forth. Without either, the loop falls apart within a few turns.

Getting started

Most agents are command-line programs — Claude Code, Codex CLI and similar. You install one and talk to it in a terminal. They're independent, so running several means running several terminal windows.

Aiglade handles that layer: it collects those command-line agents into one desktop window with a shared task queue and a single approval gate. The agents stay what they were; you just stop switching windows.

Next: how agents differ from ChatGPT.