Open Source Knowledge Base

Harness
Engineering
Guide

The open guide to building AI agent runtimes.
From core concepts to production patterns.

14 Tutorials4 Core Concepts5 Practice GuidesReal Code Examples

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Getting Started

What is a Harness?

Your First Harness

Harness vs. Framework

Core Concepts

Agentic Loop

Tool System

Memory & Context

Guardrails

Practice

Context Engineering

Sandbox

Skill System

Sub-Agent

Error Handling

Multi-Agent Orchestration

Scheduling & Automation

Long-Running Harness Design

Managed Agents Architecture

Eval Infrastructure Noise

Classifier-Based Permissions

Eval Awareness

Agent Teams

Initializer + Coding Agent Pattern

Reference

Implementation Comparison

Glossary

Showcase

Shipping Our Windows Client

Ghost Account Hunting Post-Mortem

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