Building agents from scratch is hard. Frameworks make it easier.
LangGraph lets you build agents as state machines with nodes and edges. Each node is a function. Edges determine flow. You get control over exactly what happens when.
LangChain started as a way to chain LLM calls together. Now it supports full agent design with memory, planning, and tool execution.
CrewAI focuses on multi-agent systems. You define a crew of specialized agents that work together.
These frameworks handle the common problems: managing conversation history, routing between tools, handling errors, maintaining state.
One way to build: Don’t reach for a framework on day one. Build a simple agent first. Understand the patterns. Then use a framework to scale.
Frameworks add abstraction. Abstraction adds complexity. Make sure you need it before you use it.