$ find your agent harness

A curated, verified, cross-vendor directory of AI agent harnesses — the runtime scaffolding that turns a model into an agent.

◆ 74 harnesses profiled · 9-axis capability schema · last verified 2026-07-08

2 of 74 harnesses · sorted by stars

Claw Code · Community (ultraworkers; initiated by Sigrid Jin)

★ 194,649 · low

The clean-room Rust/Python rewrite of Claude Code's harness architecture born hours after the March 31, 2026 source leak — reportedly the fastest-growing repo in GitHub history (~195k stars) with permission-gated tools, MCP, agent swarms, and container-first deployment — though the project is chaotic, largely agent-maintained, and its details vary across sources.

OSS coding harnessesopen-sourcebyok✓ mcp✓ local models⛨ optional

mini-swe-agent · SWE-agent team (Princeton/Stanford)

★ 5,636 · high

A deliberately radical ~100-line Python agent with bash as its only tool (no tool-calling API, no config sprawl) that still scores >74% on SWE-bench Verified, used by Meta, NVIDIA, and IBM as a baseline/benchmarking harness and proof that scaffolding can be minimal.

OSS coding harnessesopen-sourcebyok✓ local models⛨ optional