# Agent Harnesses — LangGraph, CrewAI, AutoGen, Claude Code · AtomEons

**Route:** `atomeons.com/learn/atlas/agent-harnesses`
**Category:** Atlas
**License:** CC-BY 4.0 unless otherwise noted on the page.

## Description

An agent harness is the runtime that loops an LLM with tools and state. LangGraph for state machines, CrewAI for role-based teams, AutoGen for conversation graphs, Claude Code for terminal-native coding agents. What each is for, where each breaks.

## Headings

- Agent Harnesses — the loop, the tools, the state
- What it is
- How each actually works
- Receipts
- What practitioners do with it
- What it is NOT

## Body

§ Atlas · Agentic systems · runtime

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*All lab content is CC-BY 4.0. Cite as: AtomEons Systems Laboratory, Agent Harnesses — LangGraph, CrewAI, AutoGen, Claude Code · AtomEons, atomeons.com/learn/atlas/agent-harnesses.*