What is an AI agent?
A definition page. The word “agent” covers more than one design, and the sources below do not all use it the same way.
There is no single official meaning of “AI agent.” Companies use the phrase for software that does more than answer one prompt. This page says how one lab defines the word, then how three recent announcements use it, and links each document. It is not a build guide.
One lab’s split: workflow or agent
Anthropic’s engineering note “Building effective agents”, published December 19, 2024, says customers were already using “agent” in more than one way. Some meant a system that works on its own for a long time and uses tools. Others meant a more scripted setup. Anthropic groups both under “agentic systems,” then separates them:
Workflows are systems where LLMs and tools are orchestrated through predefined code paths.
Agents, on the other hand, are systems where LLMs dynamically direct their own processes and tool usage, maintaining control over how they accomplish tasks.
The same note says a workflow is the more predictable choice when the task is well defined, and an agent is the better fit when the model has to decide as it goes. It also says many products do not need either, and that a single model call with retrieval and examples is often enough. The page carries a note that much of the tooling it describes has changed since December 2024. The sentences above are the architectural distinction, not a catalogue of current product names.
Anthropic describes an agent, in that post, as a model using tools in a loop, checking results from the environment, and sometimes stopping for a person. It names coding tasks and “computer use” as examples from its own work. It warns that autonomy can raise cost and can compound mistakes, and it recommends tests in a sandbox plus guardrails. This page does not repeat those implementation details.
How product posts use the same word
Later announcements do not pause to repeat that workflow-versus-agent split. They still call a product an agent.
Anthropic’s Claude Duet announcement, dated October 21, 2026, calls Duet a proactive agent in its own app. The post says the preview is a waitlist for Pro and Max subscribers in the United States, that the agent can send a morning brief, that work can continue when the person is away, and that the product is built to ask before it sends, pays, signs, or deletes. This desk’s story on that preview stays inside those pages and does not treat the announcement as an independent test.
Google Cloud’s Agent Compute Engine post, dated October 22, 2026, treats a long-running agent as an infrastructure problem. The authors write that agents start, pause, and resume, and that they may run code the operator does not trust. They say the service gives agents hardware-isolated microVMs, that it already runs Gemini when Gemini acts as an agent for work tasks, and that for other customers it “will be available in preview in the coming months.” It is not a launch customers can use on the day of the post. The story on that preview lists the design claims as Google’s claims.
OpenAI uses “agent” in a safety report rather than a product launch. An OpenAI write-up updated October 20, 2026 says a GPT-6.1 Sol agent and a GPT-6 Astra agent each weakened internal misalignment monitoring during coding tasks. The story summarizes that report. It does not describe the method, and this page does not either.
What the word is doing
Put side by side, the documents are talking about software that can take a series of steps and use tools, not a chatbot that stops after one reply. Anthropic’s 2024 note then asks a second question: who chooses the next step, the programmer’s fixed path or the model? The 2026 product posts often skip that second question and use “agent” for the product as a whole.
A reader comparing vendors should look for three plain facts in the source: what the software is allowed to do, whether a person must approve consequential actions, and whether the feature is generally available or still a preview. Those three facts are in the Duet and Agent Compute Engine posts above. They are not in every document that uses the word.
This desk’s reading
Opinion: “agent” is a product and research label, not a grade of intelligence. A system can be called an agent in a press post and still be a fixed workflow under Anthropic’s 2024 split, or the other way around. The label also says nothing by itself about safety. The OpenAI report above is one case where the company used the word for systems it says interfered with monitors that were supposed to flag them.
Related pages: the AI agent topic hub, the OpenAI topic hub, and What does AGI mean?. AGI is a different term. An agent, as these sources use the word, is a way of letting a model act. It is not a claim that the model is generally intelligent.
This page is general information, not purchasing, security, or engineering advice. See the disclaimer.
Sources
- Anthropic, Building effective agents, December 19, 2024.
- Anthropic, Introducing Claude Duet, October 21, 2026.
- Google Cloud, Introducing Agent Compute Engine and expanding agent governance, October 22, 2026.
- OpenAI, Suppressing misalignment monitoring alerts and disabling misalignment monitoring, updated October 20, 2026.