Choosing an agent framework

What you’ll learn

This is lesson 3 of Track 20, closing Phase 1 (What an agent actually is). Having seen that an agent is a loop you could build yourself, you face the question everyone rushes: which framework? This lesson slows it down. The honest first decision is whether to use a framework at all, and the lesson gives you a clear-eyed way to make that call. If the answer is yes, it surveys the framework landscape by category so you can match a framework to your task by fit instead of chasing the loudest name. The throughline is fit, not ranking: there is no best framework, only best-for-a-job.

The track structurally mirrors Microsoft’s “AI Agents for Beginners” (MIT-licensed); this lesson borrows its fit-question framing and draws breadth from the Berkeley CS294 lecture by the creators of AutoGen and LlamaIndex. Full attribution is in this lesson’s references.

Where this fits

This lesson closes the foundational phase. Lessons 1 and 2 built the loop and the tool-call mechanism; this lesson decides whether to build that machinery yourself or adopt it. The next lesson opens Phase 2 by going deep on the single most important building block underneath every framework: how to define a tool well so the model reliably knows when and how to use it.

Before you start

Prerequisites: Lessons 1 and 2. You need the loop (Lesson 1) and the four-step tool-call exchange (Lesson 2), because the whole lesson rests on the fact that you could write that machinery yourself, which is what makes “do I need a framework” a real question. No coding or math required.

By the end, you’ll be able to

Decide whether to hand-roll the agent loop or adopt a framework, by the weight of the task
Describe what a framework provides (loop plumbing plus opinionated building blocks)
Match a task to the right framework category (orchestration, retrieval-first, graph/state, managed service)
Choose among frameworks by fit (task shape, control, data/infra, maintainership), never by ranking
Explain why understanding the underlying loop keeps you free of any single library

Time and difficulty

Read time: about 11 minutes
Practice time: about 20 minutes (seven self-check questions, hand-roll-or-adopt and task-to-category exercises, plus ten flashcards)
Difficulty: standard