Google Open-Sources Harness2, a Recursive Agent Harnessing Framework
Google Cloud AI Research has open-sourced Harness² . It is a recursive agent harnessing framework that improves the code and files around a frozen model. For developers, the pitch is simple. Your agent may get better without a better model. TL;DR Size: A framework, not a model. 0 parameters trained; 8 editable harness components. Version 0.1.0 . Runs on: Linux with Python 3.12 or 3.13 and uv. Model runs call models through Vertex AI. GPU requirement: Not disclosed. Performance: 1 refinement step improved all 4 model and harness setups on all 3 benchmarks. Best: GLM-5 under OpenCode rose from 64.2 to 75.7 on WorkBuddy-Bench (+11.5 points). Worst: GLM-5 under Codex gained only 1.2 points on JobBench (23.6 to 24.8). What is Harness²? Harness² is a plug-and-play framework from Google Research that refines an agent’s harness during deployment. A harness is everything around the model: prompts, tools, memory, skills and orchestration . Harnessing ...
