Harness the agent. Then harness its self-improvement.
Harness² from Google Research is a plug-and-play recursive agent harnessing framework that lets LLM agents automatically evolve their execution harnesses (prompts, tools, memory) for open-world tasks—without ground-truth verifiers. Dual recursion: task-level Propose-Probe-Compose refinement + harnessing-level accumulation of reusable experience. Up to +11.5 points on professional benchmarks like WorkBuddy-Bench.
Harness² launched on Product Hunt on 2026-10-20 and has 189 upvotes and 7 comments so far.
Pricing details for this tool haven’t been verified yet — check the tool’s website for current plans.