omarkamali/harmony-inspector

Harmony Inspector

Deep inspection and visualization of OpenAI harmony-formatted conversations.

What is this?

Harmony Inspector is a tool for visualizing and debugging harmony-formatted conversations - the response format used by OpenAI's open-weight gpt-oss models.

Features

• —Visual token inspection - Color-coded display of harmony tokens with semantic highlighting
• —Message parsing - Extract structured messages from harmony text
• —Split view - Side-by-side visualization with synchronized hover
• —Tooltips - Hover over any token to understand its purpose
• —Error detection - Identify parsing issues with helpful suggestions
• —Debug mode - Step through parser state transitions

What is Harmony Format?

Harmony is a structured format that encodes conversations between users and AI assistants. It uses special tokens to mark message boundaries, roles, channels, and other metadata:

• —<|start|> - Begins a new message
• —<|message|> - Separates header from content
• —<|end|> - Ends a message
• —<|channel|> - Specifies output channel
• —<|constrain|> - Sets content type
• —<|call|> - Signals a function call
• —<|return|> - Signals end of response

Example

<|start|>user<|message|>Hello!<|end|><|start|>assistant<|channel|>final<|message|>Hi there!<|end|>

Local Development

# Clone the repository
git clone https://github.com/your-repo/harmony-inspector
cd harmony-inspector

# Create virtual environment
python3 -m venv .venv
source .venv/bin/activate

# Build the harmony submodule
cd harmony
pip install maturin pydantic
maturin develop
cd ..

# Install harmony-inspector
pip install -e .

# Run the server
uvicorn harmony_inspector.web.app:app --reload

Open http://localhost:8000 in your browser.

License

MIT License

Author

Created by Omar Kamali at Omneity Labs

Built with openai_harmony