What are AI agent components? (And the two people skip)

What an agent is actually made of

Strip the marketing off and every AI agent has five parts. A goal, written in plain sentences, that says what done looks like. A model, the AI that reads the situation and picks the next step. Tools, the apps it is allowed to touch: Gmail, a spreadsheet, Slack, a billing system. Memory, whatever it carries from one step or one run to the next. And guardrails, the rules it cannot break, including the points where it has to stop and ask a person.

Why no two component lists match

Search this term and the counts disagree. One vendor explainer breaks an agent into 8 modules, down to perception and state management. OpenAI's agent guide names 6: model, instructions, tools, guardrails, handoffs, and sessions. Microsoft Copilot Studio shows an agent as 3 things you fill in, instructions, knowledge and tools, plus a trigger for agents that run on their own. Same machine, three vocabularies. Instructions and profile are the goal. Knowledge and sessions are memory. Once the words map onto each other, a builder screen stops looking like a black box.

The two parts left blank

Model and tools get all the attention because they are dropdowns and picking them is fun. Memory and guardrails are usually the empty ones when a setup breaks. An agent with no memory treats every run as its first, so it emails the same person twice and repeats yesterday's mistake. An agent with no guardrails has nowhere to stop. Fill in both before the demo becomes a real process, and put a human approval on anything that sends, pays, or deletes.