AI Agent Harnesses

Point-in-time snapshot: April 2026

A curated list of projects describing themselves as AI agent harnesses or related to "harness engineering."

A Note On Terminology

The term "agent harness" emerged in late 2025 / early 2026 as a way to describe the orchestration layer that runs an AI agent. A harness manages the tool-dispatch loop, permissions, context, and lifecycle of an agent — as distinct from a framework (which provides higher-level abstractions for building agents) or a backend (which provides the inference and model serving).

The term gained traction partly through the adjacent concept of "harness engineering" — the practice of configuring and optimizing these orchestration layers (writing CLAUDE.md files, designing tool schemas, structuring agent prompts, etc.).

This list captures projects that self-identify with the "harness" label as of April 2026. The terminology is still fluid and not universally agreed upon — some projects listed here blur the line between harness, framework, and agent platform.

Agent Harnesses

Projects that provide runtime orchestration for AI agents — tool dispatch, conversation loops, context management, and agent lifecycle.

• bytedance/deer-flow — Open-source long-horizon SuperAgent harness that researches, codes, and creates. Handles tasks from minutes to hours using sandboxes, memories, tools, subagents. · Python · 57,759

• code-yeongyu/oh-my-openagent — Agent harness (previously oh-my-opencode) with multi-provider support. · TypeScript · 48,154

• langchain-ai/deepagents — Agent harness built with LangChain and LangGraph. Planning tool, filesystem backend, and subagent spawning. · Python · 19,118

• aden-hive/hive — Outcome-driven agent development framework and runtime harness. Self-improving, human-in-the-loop. · Python · 10,038

• xerrors/Yuxi — Agent harness integrating LightRAG knowledge base and knowledge graphs. Built with LangChain + Vue + FastAPI, supports MCP. · Python · 4,805

• mindfold-ai/Trellis — Agent harness for agentic coding workflows. · Python · 4,610

• HKUDS/OpenHarness — Open Agent Harness. · Python · 3,363

• can1357/oh-my-pi — AI coding agent for the terminal — hash-anchored edits, optimized tool harness, LSP, subagents. · TypeScript · 2,646

• kevinrgu/autoagent — Autonomous harness engineering. · Python · 2,084

• chrysb/alphaclaw — Setup harness for OpenClaw. Deploy in minutes, stay running for months. · JavaScript · 943

• e10nMa2k/cc-mini — Ultra-light harness scaffolding for AI agents, a mini version of Claude Code. · Python · 677

• truffle-ai/dexto — Coding agent and general agent harness for building and orchestrating agentic applications. · TypeScript · 608

• Chachamaru127/claude-code-harness — Claude Code dedicated development harness — autonomous Plan-Work-Review cycle. · Shell · 420

• aristoteleo/PantheonOS — Evolvable, distributed agent framework and harness for data science and bioinformatics. · Python · 370

• MaxGfeller/open-harness — Code-first, composable SDK to build powerful AI agents. · TypeScript · 337

• vortezwohl/Autono — ReAct-based highly robust autonomous agent (harness) framework. MCP support. · Python · 209

• aiming-lab/AutoHarness — Automated harness engineering for AI agents — audit, governance, safety. · Python · 181

• dust-tt/srchd — Research agents harness. · TypeScript · 69

• thu-nmrc/OpenHarness — Fully autonomous AI agent execution framework for OpenClaw built on harness engineering. From Tsinghua University. · Python · 62

• thu-nmrc/OpenHarness-For-Codex — Specialized variant of OpenHarness designed for AI-driven software development. · Python · 39

• mastersof-ai/harness — Agent runtime with full system prompt control. Define agents in markdown, run in terminal TUI or web UI. Powered by Claude Agent SDK. · TypeScript · 31

Resource Lists & Guides

Projects focused on curating resources, guides, and best practices for harness engineering rather than providing a harness runtime.

• walkinglabs/awesome-harness-engineering — Awesome tools and guides for harness engineering. · 1,264

• AutoJunjie/awesome-agent-harness — Curated list of agent harness projects, orchestration tools, and developer resources. · 277

• Picrew/awesome-agent-harness — Awesome list of agent harness engineering resources — projects, tools, benchmarks, and guides. · Python · 109

• alchemiststudiosDOTai/harness-engineering — Harness engineering discussion — shortcuts, automation, hacks, and productivity with code agents. · Shell · 87

• jrenaldi79/harness-engineering — Context engineering for coding agents — CLAUDE.md templates, enforcement, and best practices field guide. · JavaScript · 55

Star counts as of April 2026. This is a static snapshot and will not be updated.