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Dev mode runs the web viewer with mock data, allowing UI development and testing without consuming LLM API credits.

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Usage

helios dev
Then open http://localhost:8080 in your browser.

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What It Does

Dev mode starts the web viewer server with simulated:
  • Agent messages and reasoning
  • Tool calls and outputs
  • Screenshots
  • Progress updates

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Use Cases

UI Development

Iterate on the web viewer interface without API costs

Testing

Verify trace rendering and WebSocket connections

Offline Work

Work without internet or API credentials

Demos

Show the viewer without running real tasks

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Mock Data

Dev mode simulates a typical agent session: 
[Agent] Analyzing the task requirements...
[Tool] bash: echo "Hello World" > /home/hello.txt
[Result] Command executed successfully
[Agent] File created. Verifying...
[Tool] bash: cat /home/hello.txt
[Result] Hello World
[Agent] Task completed successfully.

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Customizing Mock Data

For custom mock traces, modify the dev mode implementation in src/helios/server/app.py.

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Web Viewer Development

The web viewer frontend is located at: 
src/helios/server/helios-viewer/
├── src/
│   ├── App.tsx
│   ├── components/
│   └── ...
├── package.json
└── ...

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Running the Frontend Separately

For hot-reload during frontend development: 
cd src/helios/server/helios-viewer
npm install
npm run dev
This starts a Vite dev server with hot module replacement.

Web Viewer

Using the web viewer with real tasks

Contributing

Contribute to Helios development