https://github.com/HarnessRouter/harnessrouter
[image: HarnessRouter]
The unified interface for agent harnesses.
[image: GitHub Stars, exact count] [image: License: Apache 2.0] [image: Docker pulls] [image: UHP conformance: Full] [image: OpenAI Responses: Compatible]
Build agent products without handling harness engineering. HarnessRouter is the infrastructure layer that turns existing harnesses like Codex and Claude Code into plug-and-play agent backends, letting your product run tasks, retrieve results, and switch harnesses through one API.
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[image: Animated diagram comparing separate harness integrations with one HarnessRouter API. Without HarnessRouter, four harnesses require 36 integration responsibilities, increasing to 45 with a fifth. With HarnessRouter, the product keeps one integration as harnesses are added.] [[image: Animated diagram comparing separate harness integrations with one HarnessRouter API. Without HarnessRouter, four harnesses require 36 integration responsibilities, increasing to 45 with a fifth. With HarnessRouter, the product keeps one integration as harnesses are added.]
](https://github.com/HarnessRouter/harnessrouter/blob/main/docs/images/2026-09-13-harnessrouter-integration-comparison-cropped-v5.gif)
HarnessRouter implements the Unified Harness Protocol (UHP) and provides an OpenAI Responses-compatible API, handling persistent sessions, streaming progress, files, artifacts, cancellation, and structured failures.
Switch harnesses. Optimize cost and latency.
[image: Cost: 99.8% lower, from 223 to 0.47 credits. End-to-end latency: 3.2 times faster, from 4m 36s to 1m 25s. Eight harness and model configurations on the same task. Each metric compares its best and worst results. The lowest-cost and fastest configurations vary by task.]
Eight harness × model configurations on the same task. Each metric compares its best and worst results. The lowest-cost and fastest configurations vary by task. Methodology
26 harness bases today: Codex, Claude Code, Hermes, Pi, DeepSeek Harness, OpenCode, Kilo Code, Qwen Code, Gemini CLI, Cline, Oh My Pi, goose, Kimi Code CLI, MiniMax Code, Aider, OpenHands, CheetahClaws, Grok Build, Agent Zero, System One, Qoder Cloud Agent, MiMo Code, jcode, OpenSquilla, nanobot and ZeroClaw. The support matrix shows which run on which provider.
Tip
Get started: Run locally · Integrate into your product · Starter kits · Use managed Cloud
Quickstart
Self-host Community Edition with your own provider keys, on infrastructure you control.
Start with one Docker command, wait for the first launch, then connect a model provider and run your first task.
You need: Docker · About 4 GB of disk · A provider API key
No HarnessRouter account required. No bundled model or trial key.