Harness²

Open-source research framework from Google Research for recursive agent harnessing: it edits an agent's harness (system prompt, guardrails, memory, tools, subagents, skills, scripts, plugins) for each task without changing model weights, and keeps lessons for future tasks. Uses OpenCode or Codex as executors.

Use case

Agent frameworks

Pricing tier

Free

Pricing note

Open source (Apache-2.0); model-backed runs use your own model access.

Skill level*

Advanced

License

Apache-2.0

Added

2026-10-18

Sources checked

• github.com/google-research/harness2
• harness2.github.io
• arxiv.org/abs/2610.14224

* Skill level and vibe badges are our own editorial labels. Pricing and plans change often; always confirm on the official site. Last checked 2026-10-18.