Strands Harness SDK
strands-agents/harness-sdk
Build an agent harness and control it end-to-end.
The Strands Harness SDK is AWS's purpose-named harness toolkit: a model-driven Python SDK with decorators for tools, native MCP and multi-agent composition — 'build an agent harness and control it end-to-end' is literally the pitch.
In the news
DeepSeek ships Harness Desktop; the 'everything is a plugin' harness passes 240k stars
DeepSeek releases a macOS and Windows Desktop app for DeepSeek Harness, its open-source agent harness where everything — tools, sub-agents, even the loop — is a plugin. The repo passed 240k stars within three months of its August launch, making it the fastest-growing harness in the field's history.
Best of Agent Harnesses tracks 167 harnesses — and their graveyard
The Best of Agent Harnesses list ranks 167 agent harnesses weekly by capability, autonomy and recovery, ships an MCP server so agents can pick their own harness, and maintains a graveyard that flagged a 268k-star repo for suspected star manipulation. Curation itself becomes harness infrastructure.
HarnessTax: harness choice swings agent cost more than model choice
Arena.ai's HarnessTax study tests 21 model–harness combinations across Claude Code, Codex CLI and Pi, finding harness choice can significantly change cost even at similar task success rates. Weeks earlier, SWE-bench Pro analysis showed swapping harnesses moved pass@1 more than model upgrades (23%→52% on GLM-5.2) — and that harness rankings barely transfer across models.
Anthropic moves MCP toward open foundation governance
Anthropic announces plans to donate MCP to a neutral foundation, with new registry, auth and sandbox specs — cementing MCP as vendor-neutral infrastructure for the entire agent ecosystem.
Related projects
OpenClaw
openclaw/openclaw
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.
DeepSeek Harness
deepseek-ai/deepseek-harness
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.
AutoGPT
Significant-Gravitas/AutoGPT
The 2023 experiment that started the autonomous agent wave.
AutoGPT gave GPT-4 a loop, a memory and tools and let it run — kicking off the entire autonomous-agent category. Now rebuilt as a platform for building, deploying and continuously improving agents.