Orion Browser

A privacy-first, AI-native Chromium fork that runs browser agents locally. Your keys, your data, your machine.

What is Orion?

Orion is a custom Chromium browser with a built-in AI agent system. It combines a patched Chromium build with a powerful Chrome extension that enables browser automation, MCP server integration, and local LLM support.

orion-browser/
|
|-- packages/orion/            Chromium build system + patches
|   |-- build/                 Python build scripts and configs
|   |-- chromium_patches/      Source patches applied to Chromium
|   |-- chromium_files/        Additional files injected into Chromium
|   |-- resources/             Icons, version info, entitlements
|   |-- series_patches/        Ordered patch series
|   `-- tools/                 Build utilities
|
|-- packages/orion-agent/      Chrome extension (AI agent)
|   |-- apps/
|   |   |-- agent/             Main agent UI (side panel, new tab)
|   |   |-- server/            Local agent server (Node.js)
|   |   |-- controller-ext/    Browser controller extension
|   |   `-- eval/              Agent evaluation framework
|   |-- packages/              Shared libraries
|   `-- tools/                 MCP server, CLI tools
|
`-- docs/                      Project documentation

Core Capabilities

• Browser Agent -- AI-powered automation that runs in your browser, not in the cloud
• MCP Server -- 31 tools exposing browser control to Claude Code, Gemini CLI, or any MCP client
• Workflows -- Visual graph builder for repeatable browser automations
• Cowork -- Combine browser automation with local file operations
• Scheduled Tasks -- Run agents on autopilot at configurable intervals
• LLM Hub -- Compare Claude, ChatGPT, and Gemini side-by-side on any page
• Ad Blocking -- Built-in uBlock Origin with Manifest V2 support
• Privacy Patches -- Enhanced privacy from ungoogled-chromium patches
• Local LLM Support -- Ollama and LMStudio integration, no cloud required

Development

Agent Development (recommended starting point)

The agent is a Chrome extension. Most development happens here.

cd packages/orion-agent
bun install
cp .env.example .env    # Add your LITELLM_API_KEY
bun run build:dev

Load in any Chromium browser:

1. Open chrome://extensions/
2. Enable Developer mode
3. Click Load unpacked
4. Select packages/orion-agent/dist/

Browser Development

Building the Chromium fork requires ~100GB disk and 16GB+ RAM. Only needed for browser-level patches.

# First: follow https://www.chromium.org/developers/how-tos/get-the-code/
# Then:
cd packages/orion

# Debug build
python build/build.py --config build/config/debug.linux.yaml \
  --chromium-src /path/to/chromium/src --build

# Release build
python build/build.py --config build/config/release.linux.yaml \
  --chromium-src /path/to/chromium/src --build

See CONTRIBUTING.md for detailed setup instructions.

Roadmap

Phase 1 -- Foundation (current)

• Rebrand and fork from upstream
• Establish independent build pipeline
• Set up CI/CD for agent and browser builds

Phase 2 -- Agent Enhancements

• Improved tool reliability and error recovery
• Better multi-tab coordination
• Enhanced workflow builder
• Agent memory and context persistence

Phase 3 -- Browser Integration

• Deeper Chromium-level agent integration
• Custom DevTools panels for agent debugging
• Native sidebar improvements
• Performance profiling for agent actions

Phase 4 -- Platform

• Plugin system for third-party agent tools
• Shared workflow marketplace
• Cross-device sync (encrypted, self-hosted option)

Architecture

The system has two main components that communicate over a local WebSocket/HTTP connection:

Orion Browser (Chromium fork) -- A patched Chromium build that includes a local server proxy, extension management, metrics collection, and custom UI (welcome page, settings). The build system applies patches from chromium_patches/ to the Chromium source tree and produces platform-specific binaries.

Orion Agent (Chrome extension) -- A multi-app extension system:

• agent -- Main AI agent with side panel UI, new tab page, and LLM integrations
• server -- Local Node.js server providing tool execution, file operations, and MCP endpoints
• controller-ext -- Browser controller handling tab management, navigation, and DOM interaction
• eval -- Testing and evaluation framework for agent quality

License

AGPL-3.0. See LICENSE.

Credits

• ungoogled-chromium -- Privacy patches
• The Chromium Project -- The foundation