What is an AI agent?
An AI agent is a system that pursues a goal by deciding its own next action, rather than following a predetermined script. It runs a loop — reason about the goal, take an action (usually a tool call), observe the result, repeat — until the goal is met or a limit stops it. The defining property is that the sequence of steps is chosen at runtime, not written in advance.
The agent loop
Strip away the frameworks and every agent runs the same cycle:
- Observe — take in the goal and the current state
- Reason — decide what to do next
- Act — call a tool, run code, request information
- Observe the result — feed the outcome back into context
- Repeat until done, blocked, or out of budget
Step five is where production agents live or die. Without a step budget and an explicit halt condition, a confused agent does not stop — it loops, and the failure presents as an unexpected bill rather than an error.
Agent vs chatbot vs workflow
These three get used interchangeably and are genuinely different:
| Decides its own steps | Uses tools | Runs unattended | |
|---|---|---|---|
| Chatbot | No | Sometimes | No |
| Workflow | No — fixed path | Yes | Yes |
| Agent | Yes | Yes | Yes |
A chatbot responds. A workflow executes a path someone designed. An agent chooses the path. That autonomy is the entire value proposition and the entire risk.
What an agent needs
Tools. An agent with no tools is a chatbot. Tools are how it affects anything.
Memory. The context window holds the current task; anything that must survive it needs real storage. "Agent memory" is almost always a retrieval system, not a property of the model.
A goal it can evaluate. An agent needs to be able to tell whether it is done. Goals with no checkable success condition produce agents that either stop too early or never stop.
Boundaries. Step budgets, approval gates for irreversible actions, and sandboxed execution.
Where agents fail
Compounding errors. If each step is 95% reliable, ten steps is about 60%. Agent reliability degrades multiplicatively with task length, which is why short agents work far better than long ones.
No stopping rule. Covered above, and it is the most common production incident.
Prompt injection. An agent that reads untrusted content — a web page, an email, a tool result — can be instructed by it. Anything retrieved is data, never instructions.
Doing something irreversible. Reading is recoverable. Sending, deleting, and paying are not. Those need an approval gate, not a confidence threshold.
When a workflow is the better answer
If you can write down the steps, write down the steps. A deterministic workflow is cheaper, faster, auditable and testable. Agents earn their cost when the path genuinely cannot be known in advance — variable inputs, open-ended research, or tasks where the next step depends on what the last one returned.
The most reliable production systems are usually mostly workflow with a small agentic step in the middle, not an agent from end to end.
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Explore the AI agents directoryFrequently asked questions
- What is the difference between an AI agent and an AI workflow?
- A workflow follows a path a person designed in advance. An agent chooses its next step at runtime based on what it has observed. Workflows are more predictable and cheaper; agents handle situations that could not be fully specified up front.
- Are AI agents reliable enough for production?
- For short, bounded tasks with reversible actions, yes. Reliability degrades multiplicatively with the number of steps, so long autonomous chains are still fragile. Production systems typically bound the agent tightly and gate anything irreversible behind human approval.
- What is a multi-agent system?
- Several specialised agents coordinating on a task one agent could not complete alone, usually with an orchestrator routing work between them. It adds capability and also adds the failure modes of every handoff.
- Do AI agents remember previous conversations?
- Only if something stores that information and retrieves it. The model itself does not learn from your sessions — persistence is a database or vector store the agent queries, not a property of the model.
Related terms
- Multi-agent system
- Several specialized AI agents cooperating on one objective — e.g., a researcher, a writer, and a reviewer passing work between them.
- Agentic loop
- The repeating cycle of think, act, observe that an agent runs until it finishes or hits a limit. The limit matters — without one, failure looks like an infinite bill.
- Tool call
- A model's request to run a named function with structured arguments. The mechanism by which a model does anything beyond producing text.
- MCP (Model Context Protocol)
- An open protocol for connecting AI assistants to external tools and data sources through standardized servers.
- Guardrails
- Constraints around AI systems — input validation, output filtering, human approval gates — that keep automated AI behavior inside acceptable bounds.