An AI agent is software that uses a language model to work toward a goal: it decides the next step, calls a tool to carry it out, reads the result and repeats until the task is done or it hands over to a person.
That loop separates an agent from a chatbot, which answers a message and stops, and from a scripted automation, which follows steps a developer fixed in advance. An agent chooses its steps at run time. That lets it handle requests nobody scripted, and it also means it can choose badly. Most of the engineering in an agent project goes into limiting and checking those choices.
An agent is the right tool when a task needs judgment across several steps and the inputs vary too much to script: answering a phone call, triaging a support ticket or changing code in a repository. When the steps are always the same, a plain workflow is cheaper and more predictable, and we say so during scoping.
Scripted automation, LLM chatbot and AI agent compared | Scripted automation | LLM chatbot | AI agent |
| Who decides the next step | The developer, in advance | The user, one message at a time | The model, at run time, within set limits |
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| Acts in other systems | Yes, on fixed paths | Usually not | Yes, through the tools it is allowed to call |
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| Fits best | Stable, repeatable processes | Questions and answers | Multi-step tasks with varied inputs |
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| Main risk | Breaks when inputs change | Wrong or invented answers | Wrong actions, loops and runaway cost |
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