# What an Agent Is — Agent Frameworks and MCP Basics

Source: https://www.geekswithgeeks.com/en/agent-frameworks-mcp/af-what-is-agent

> Define an agent as a model plus tools plus a loop and tell it apart from a chatbot.

## Model, tools, loop

A chatbot answers from what it already knows. An **agent** can also take actions: it is a language model given **tools** (functions it may request) and run in a **loop** until it decides the task is finished. The model never runs a tool itself; it asks, and your program does the work.

## Think, act, observe, repeat

An agent is a model in a loop: it chooses an action, your code runs it, and the result goes back to the model.

![Four stages that repeat until the task is done.](assets/figures/agent-frameworks-mcp/section-1-map.svg) — Figure 1.1 — Model call, tool call, result, repeat.

## A manager and a clerk

The model is a manager who says "fetch me order 42". The clerk (your code) fetches it and hands back the file. The manager reads it and decides the next instruction.

## Not every task needs an agent

If the steps are fixed, a plain function or a short chain is cheaper and more predictable. Use an agent loop when the path depends on what the tools return.

**Quiz:** Who actually executes a tool call?

- [ ] The language model itself
- [x] Your application code
- [ ] The user's browser
- [ ] The GPU

*Answer:* Your application code. The model only requests a call; your program runs the function and returns the result.