Find everyone building the agent harness layer

Cognition builds Devin, an autonomous AI software engineer that plans and executes engineering tasks end-to-end, and acquired the Windsurf agentic IDE in 2025. One of the defining startups of the coding-agent wave.

LangChain makes the LangChain framework and LangGraph, the low-level orchestration standard for stateful, controllable agents, plus the LangSmith platform for tracing, evaluating and monitoring them in production.

OpenHands (formerly All Hands AI, born from the OpenDevin project) builds the major open-source coding-agent platform — agent canvas, sandboxed execution, SDK and an enterprise control plane — now rebranded under the project's name.

The viral open-source personal AI assistant that really does things.

OpenClaw (born as Clawdbot in late 2025) is a self-hosted personal agent that connects your chats, email, browser and terminal into one always-on assistant. Its explosive growth — hundreds of thousands of stars within months — made 'personal agent harness' a mainstream category.

The agent that grows with you.

Nous Research's self-improving personal agent: a learning loop turns experience into reusable skills, builds a persistent user model across sessions, and checkpoints state to disk with rollback — lean enough for a $5 VPS and driven from the chat apps you already use.

Everything is a Plugin — DeepSeek's open agent harness.

DeepSeek Harness is the breakout open-source harness of 2026: an architecture where everything — tools, subagents, even the loop itself — is a plugin. A Desktop app for macOS and Windows followed in October 2026, and the project passed 240k stars in under three months.