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HarnessRouter

Run many AI coding agents, like Codex and Claude Code, through one self-hosted interface and API.

What it does

HarnessRouter lets you run many existing AI agent tools, which it calls "harnesses", from one place. Examples include Codex, Claude Code, Gemini CLI, Aider and goose. You can switch between them without rebuilding your product.

It runs on your own computer or server using Docker (a tool that packages software so it runs the same everywhere). You open a web console in your browser, add an API key from an AI provider, pick a harness and give it a task. You can watch its progress live and open the files it creates.

For developers, it offers one API (a doorway that lets programs talk to each other) that works like OpenAI's Responses API. It handles ongoing sessions, live progress updates, files, cancelling tasks and error reports. You can also build custom harnesses with your own instructions, tools and skills.

Who it's for

Developers and teams building products on top of AI agents who want to try or switch between different agent tools. Also people who want to run agent tasks from a browser console on their own machine.

Can I use it without coding?

With some setup. You start it with a Docker command, then use a browser console to add a provider key and run tasks. New to this? Start here.

Can I run it?

Cost
Free, but needs an AI accountThe software is free, but it uses an online AI service (like OpenAI or Anthropic), which usually charges for use.
Runs on
Server, Web browser
Privacy
Sends what you give it to an online service
API key
Needed. An API key is a password-like code from an online AI service. What's that?

Try it

  1. Install Docker and start HarnessRouter with the single command shown in the README.
  2. Open the console in your browser, sign in with the default login, and change the password.
  3. Add an API key from an AI provider, then choose a harness and start a new task.

Using Claude Code, Cursor or another AI coding assistant? Paste the prompt and it will walk you through the setup.New to this?

Before you install

  • Only download from the official GitHub page. Copies with similar names exist for many popular projects.
  • Plain-AyI is an independent guide and doesn't host or review the software it lists. Please check each project's official page before installing.
  • License (Apache-2.0): Permissive: free to use, change and share, including for business.
  • Keep your API key private. Never paste it into websites or share it, and set a spending limit with the AI service.
  • What you type or upload is sent to an online service. Avoid sharing private or sensitive information.
  • More on staying safe

Where people are talking about it