An agent works in a loop: it plans a step, carries it out with a tool, looks at the result and decides on the next step. It repeats that until the goal is reached, or until it needs a human. Four components make the difference.
1. Planning
The agent breaks the goal into steps. 'Answer this complaint email' becomes: read the email, look up the customer, find the order, check the delivery, work out what went wrong, write a reply and propose a solution. The language model does the planning. The better a model can reason, the longer and more complex the tasks it can handle.
2. Tools
Without tools, an agent is just a chatbot. Tools are its hands: a connection to Exact, AFAS or HubSpot, access to the mailbox, a search function across your documents. Increasingly that runs through MCP, the Model Context Protocol. It's an open standard Anthropic introduced in November 2024, so that AI models can talk to systems in one consistent way. In December 2025, Anthropic handed MCP over to the Agentic AI Foundation, part of the Linux Foundation. ChatGPT, Gemini and Microsoft Copilot now support it too (Anthropic, 2025).
The most important design choice sits here: which tools does the agent get, and with which permissions? An agent that can read orders but not change them can't break much.
3. Memory
An agent has two kinds of memory. Short-term memory is the context window: everything it reads and does within one task. Long-term memory is what it keeps between tasks, such as earlier contact with the same customer, or a knowledge base with your product information and examples of good work. Looking that up is often called RAG: the agent first finds the right pieces and bases its answer on them, instead of talking off the top of its head.
This is also where the biggest pitfall lies. An agent is only as good as the information it can find. If your prices live in three different Excel files, it will hesitate just like a new employee would. That's why AI often starts with data, not AI.
4. Human in the loop
A good agent knows when to stop. With us, there's always a human in the process: the agent prepares, an employee checks and presses send. That's called human in the loop. The more trust there is, the bigger the steps the agent may take on its own. You build that trust with numbers, not hope. Why that works is explained in why your AI agent needs a boss.