HarnessRouter: Unified interface for agent harnesses

In plain words

HarnessRouter is a unified API that lets developers run multiple AI agent systems—including Codex, Claude Code, and Hermes—through a single interface. The self-hosted Community Edition implements the Unified Harness Protocol, an open standard, and handles sessions, streaming, file management, and error handling. It's designed for product teams who want to leverage best-in-class agent harnesses from frontier labs and open-source communities without building their own infrastructure, using their own infrastructure and API keys.

written from the facts on this page · September 2026

From the sources

HarnessRouter Community Edition: the self-hosted, Apache-2.0 edition of the unified interface for agent harnesses. Run Codex, Claude Code, Hermes, PI, DSH, and more through one API, with sessions, streaming, files, cancellation, and failure handling. Implements the Unified Harness Protocol (UHP), an open standard. Your keys, your infrastructure. - HarnessRouter/harnessrouter

In the maker’s words, at launch

Hey HN! We are building HarnessRouter, a canonical API for running Codex, Claude Code, Hermes, and other managed agent harnesses as your product backend. Before building HarnessRouter, I used to build our own agent harness for our products. I tried LangGraph, agent SDKs from different vendors, pydantic, LLM tool use…

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