victauri-browser

Native messaging host + browser extension that brings Victauri's MCP inspection to any website -- not just Tauri apps.

How It Works

MCP Client → axum HTTP :7474 → Native Messaging (stdio) → Browser Extension → Content Script → Page

The Rust binary serves dual roles: HTTP server for MCP clients AND native messaging host for the browser extension. The extension injects a JS bridge into every page, giving agents the same DOM/interaction/inspection tools that victauri-plugin provides inside Tauri apps.

Install

cargo install victauri-browser
victauri-browser-host install    # Registers native messaging host for Chrome/Edge/Brave/Arc

Then load extensions/chrome/ (or extensions/firefox/) as an unpacked extension in your browser.

Connect

Point any MCP client at http://127.0.0.1:7474/mcp, or use the REST API:

# List available tools
curl http://127.0.0.1:7474/api/tools

# Take a DOM snapshot of the active tab
curl -X POST http://127.0.0.1:7474/api/tools/dom_snapshot

Tools

20 MCP tools available through the extension:

Tool	What it does
`dom_snapshot`	Full accessible DOM tree with ref handles
`find_elements`	Search by text, role, selector, test ID
`click`	Click an element (with actionability checks)
`fill`	Set input/textarea value
`type_text`	Type character-by-character with key events
`press_key`	Dispatch keyboard events (Enter, Tab, Escape, combos)
`hover`	Trigger mouse hover events
`eval_js`	Execute JavaScript in the page
`screenshot`	Capture visible tab as PNG
`get_styles`	Computed CSS for any element
`get_bounding_boxes`	Pixel measurements with box model
`highlight_element`	Visual debug overlay
`clear_highlights`	Remove overlays
`audit_accessibility`	WCAG compliance check
`get_performance`	Navigation timing, heap, resources
`wait_for`	Poll for conditions (selector, text, URL)
`navigate`	Go to URL, go back
`get_cookies`	Read cookies for the current domain
`tabs.list`	List open browser tabs
`get_plugin_info`	Host version and status

Security

Localhost only -- 127.0.0.1, never 0.0.0.0
Bearer auth -- optional token via --token flag or VICTAURI_AUTH_TOKEN env var
Rate limiting -- token-bucket rate limiter
Origin guard -- rejects cross-origin requests
Port fallback -- tries :7474-7484 if the preferred port is taken

CLI

victauri-browser-host install      # Register native messaging host
victauri-browser-host uninstall    # Remove registration
victauri-browser-host serve        # Start HTTP server without native messaging
victauri-browser-host version      # Print version

Browser Support

Browser	Extension	Status
Chrome / Edge / Brave / Arc	`extensions/chrome/`	Full support (MV3 + CDP screenshots)
Firefox	`extensions/firefox/`	Full support (MV3, `browser.*` namespace, no CDP)

Tests

cargo test -p victauri-browser                         # 99 Rust tests
cd extensions/chrome/tests && npx vitest run           # 163 JS bridge tests

Documentation

Full API docs: docs.rs/victauri-browser

License

Apache-2.0 -- see LICENSE

Part of Victauri. Built by 4DA Systems.

victauri-browser 0.3.0