@linsoai/browser-relay

Browser Relay

Let AI agents use the same Chrome browser you use every day.

Quick Start · CLI · Remote · HTTP API · 中文

Browser Relay connects your real, logged-in Chrome to AI agents — over a plain CLI, MCP, or HTTP. Agents work inside the tabs you already have open, locally or from another machine, instead of a throwaway automation profile or a headless browser. No cloud browser, no separate automation window, no surprise tabs.

Real Chrome, not a throwaway profile

Most browser automation spins up a fresh, empty browser profile. That is fine for testing, but useless for agents that need your authenticated web apps — SaaS dashboards, admin panels, internal tools, documents, private sessions — where a headless browser or a fresh profile simply is not logged in.

Browser Relay is that missing layer:

• Your actual Chrome session — cookies, localStorage, extensions, and login state, shared as-is.
• No pop-up automation browser — it never spawns a separate window or opens tabs behind your back; navigation reuses an attached tab.
• Local or remote — drive the browser from this machine, or from anywhere through a public relay service (self-hostable on Cloudflare in one click), with no public port exposed.
• Agent-first — a bundled Skill, an MCP server, and a simple HTTP API; works with Claude, Claude Code, Cursor, Windsurf, custom agents, and scripts.
• Local-first boundary — the relay binds to 127.0.0.1 by default.

Provenance

Based on chengyixu/openclaw-browser-relay, with auto-attach behavior inspired by blakesabatinelli/openclaw-chrome-relay. Repackaged as a general-purpose local browser bridge for AI agents, without the OpenClaw-specific gateway, token auth, or platform bindings.

Architecture

Local
  AI Agent ──CLI / MCP / HTTP──▶ Relay server (Node, 127.0.0.1)
                                        │ WebSocket
                                        ▼
                                 Chrome extension ──chrome.debugger / CDP──▶ your Chrome tabs

Remote (Remote Relay)
  AI Agent ──HTTPS──▶ public relay (relay.linso.ai) ◀──WSS── Chrome extension ──▶ your Chrome tabs

Local mode is the default: the agent talks to a relay server on 127.0.0.1, which forwards Chrome DevTools Protocol commands to the extension.

Remote mode exposes nothing. When you turn on Remote Relay, the extension connects out to a public relay service; a remote CLI reaches that same service, which routes each command down to your browser over the existing connection — no open ports, no local server on the network. Use the default hosted relay, or run your own on Cloudflare in one click (see below).

Quick Start

Use Browser Relay in three steps.

1. Install

npm install -g @linsoai/browser-relay
browser-relay status

On macOS and Linux, the global install registers a user-level background service through launchd or systemd-user. The service starts on login and restarts on crash.

If the service is not running yet:

browser-relay start

2. Load the Chrome extension

Print the extension directory:

browser-relay path

Then open chrome://extensions, enable Developer mode, click Load unpacked, and select the extension directory printed by browser-relay path.

Upgrade with browser-relay update. It installs @linsoai/browser-relay@latest globally, refreshes the background service, and prints a status check; the extension reloads itself the next time it reconnects (within ~30 seconds).

3. Install the Agent Skill

Browser Relay ships with an agent-friendly Skill. Print the install command:

browser-relay skill

Then run the printed npx skills ... command and choose the agent to install it into, or run it directly with $(browser-relay skill). After that, your agent can operate your own browser without opening a separate automation browser.

Agent Friendly by Default

Browser Relay is designed to be comfortable for agents, not just low-level automation scripts.

• The included Skill tells agents when to use Browser Relay and how to interact safely.
• Page snapshots are annotated with links, buttons, inputs, and other interactive elements so agents can plan before acting.
• Actions target existing attached tabs, keeping the user's browser context visible and predictable.
• Console and network capture record console.*, page exceptions, log entries, and request/response activity for debugging real-page behavior.

CLI

The CLI is the primary interface. For agents that can run shell commands, it is faster and less error-prone than hand-writing curl JSON:

browser-relay tabs
browser-relay console --tab ABC123 --limit 50
browser-relay network --tab ABC123 --type response --status 500
browser-relay snapshot --tab ABC123 --max-length 20000
browser-relay click 'button[type=submit]' --tab ABC123
browser-relay type 'hello world' --selector 'input[name=q]' --clear --submit
browser-relay key Control+L
browser-relay scroll down --amount 1000
browser-relay screenshot /tmp/page.png --full-page
browser-relay eval 'document.title'

For long text or JavaScript, avoid shell escaping by reading from stdin:

printf 'hello\nworld' | browser-relay type --selector textarea --stdin
browser-relay eval --stdin < script.js

All browser commands accept --json for the raw API response and --tab <id> to target a specific tab. When --json is used, a failed command prints the structured error payload and exits non-zero.

Remote control (Remote Relay)

To drive this browser from another machine — a CI box, a remote agent, a different network — turn on Remote Relay in the extension's Options page. The browser connects out to a public relay service (the hosted relay.linso.ai by default); nothing listens on a public port and no local server is exposed.

Turning it on mints a secret Device ID — treat it like a password. Pass it to the same CLI commands from anywhere:

browser-relay tabs --remote-device-id br-xxxx
browser-relay eval "location.href" --remote-device-id br-xxxx

# Save an alias once so you don't retype the id (remote ls / rm to manage):
browser-relay remote add mymac br-xxxx
browser-relay tabs --remote mymac

Run your own relay instead of the hosted one — one click deploys the Worker in hub/ to your own Cloudflare account:

The button connects Cloudflare to your GitHub the first time (Workers Builds). Prefer the CLI? git clone, then cd hub && npx wrangler deploy. Either way, put the resulting …workers.dev URL in the Options page's Public relay field.

The remote-device-id is a capability — anyone with it can control this browser while Remote Relay is on. Design notes: docs/remote-control-hub.md.

CLI reference

browser-relay            # Run the relay server in the foreground
browser-relay start      # Start the background service
browser-relay stop       # Stop the background service
browser-relay restart    # Restart the background service
browser-relay fix        # Restart and clear stale session state (when tabs won't connect)
browser-relay update     # Update the global package and refresh the service
browser-relay status     # Show service state and HTTP health
browser-relay logs       # Tail /tmp/browser-relay.log
browser-relay path       # Print the Chrome extension directory
browser-relay skill      # Print the Skill install command
browser-relay install    # Register the background service
browser-relay uninstall  # Unregister the background service

browser-relay tabs       # List attached browser tabs
browser-relay console    # Print captured console/page errors
browser-relay network    # Print captured network requests/responses/failures
browser-relay snapshot   # Print annotated page text
browser-relay click      # Click an element by CSS selector
browser-relay type       # Type text into the page
browser-relay key        # Press a key or shortcut
browser-relay scroll     # Scroll the page
browser-relay screenshot # Save a PNG screenshot
browser-relay eval       # Evaluate JavaScript in the page
browser-relay download   # Print src/href for an element
browser-relay download-start # Start a Chrome download
browser-relay downloads      # List Chrome downloads and events
browser-relay remote     # Manage remote aliases (add / ls / rm)
browser-relay api-help   # Show browser command examples

MCP

After installing the npm package, use browser-relay-mcp directly:

{
  "mcpServers": {
    "browser": {
      "command": "browser-relay-mcp",
      "env": {
        "BROWSER_RELAY_URL": "http://127.0.0.1:18795"
      }
    }
  }
}

The MCP server exposes high-level tools such as browser_tabs, browser_snapshot, browser_click, browser_type, browser_key, and browser_screenshot.

HTTP API

The HTTP API is the stable integration surface for code and custom tools. For interactive agent work, prefer the CLI above.

Errors use a structured shape across HTTP, CLI --json, and MCP tool errors:

{ "ok": false, "code": "invalid_request", "error": "url is required", "message": "url is required", "status": 400, "retryable": false }

# List attached tabs
curl http://127.0.0.1:18795/api/tabs

# Take a text snapshot of a page
curl "http://127.0.0.1:18795/api/snapshot?tabId=ABC123"

# Read captured console/page errors
curl "http://127.0.0.1:18795/api/console?tabId=ABC123&limit=50"

# Read captured network activity (sensitive headers are redacted)
curl "http://127.0.0.1:18795/api/network?tabId=ABC123&type=response&status=500"

# Click an element
curl -X POST http://127.0.0.1:18795/api/click \
  -H "Content-Type: application/json" \
  -d '{"tabId":"ABC123","selector":"button.submit"}'

Endpoint	Method	Description
/	GET/HEAD	Health check
/api/debug	GET	Server diagnostics
/api/tabs	GET	List attached tabs
/api/console	GET	Read captured console/page error entries
/api/console/clear	POST	Clear captured console entries
/api/network	GET	Read captured Network.* request/response/failure entries
/api/network/clear	POST	Clear captured network entries
/api/navigate	POST	Navigate an attached tab
/api/snapshot	GET	Get annotated text or raw HTML
/api/click	POST	Click an element by CSS selector
/api/type	POST	Type into an input
/api/key	POST	Press a key or keyboard shortcut
/api/scroll	POST	Scroll the page
/api/screenshot	GET/POST	Capture a PNG screenshot; full-page mode returns capture strategy/size metadata
/api/eval	POST	Evaluate JavaScript in the page
/api/download	POST	Extract an element URL
/api/download/start	POST	Start a real Chrome download from a URL
/api/downloads	GET	List Chrome downloads and recent download events
/api/downloads/clear	POST	Clear captured download events

Real Chrome downloads require the extension's downloads permission. After upgrading from an older Browser Relay version, reload the unpacked extension in chrome://extensions.

The same endpoints are reachable remotely: a CLI running with --remote-device-id sends them through the public relay to the browser.

Configuration

Environment variable	Default	Description
BROWSER_RELAY_URL	http://127.0.0.1:18795	Relay base URL used by CLI browser commands and MCP
BROWSER_RELAY_HOST	127.0.0.1	HTTP and WebSocket bind address
BROWSER_RELAY_PORT	18795	HTTP and WebSocket port
BROWSER_RELAY_REMOTE_DEVICE_ID	—	Remote Device ID (or alias) used when no --remote-device-id flag is passed
BROWSER_RELAY_REMOTE_HOST	https://relay.linso.ai	Public relay URL for remote commands

The Chrome extension port can be changed from the extension Options page.

Service files:

macOS: ~/Library/LaunchAgents/org.browser-relay.service.plist
Linux: ~/.config/systemd/user/browser-relay.service

Logs: /tmp/browser-relay.log, /tmp/browser-relay.error.log

Hiding the "debugging this browser" infobar

Whenever the extension has a debugger attached, Chrome shows a mandatory "Browser Relay" started debugging this browser bar at the top of the page. No extension API can remove it — it is Chrome's built-in anti-abuse warning.

Two ways to deal with it:

• Automatic (default): the extension soft-detaches idle tabs after 10 min, so the bar disappears on its own while you're not using it and re-attaches on the next command. Nothing to configure.

• Remove it entirely: launch Chrome with the --silent-debugger-extension-api flag, which suppresses the bar for the debugger extension API. You must fully quit Chrome first (open --args only passes flags to a cold start):

  # macOS
  osascript -e 'quit app "Google Chrome"'
  open -a "Google Chrome" --args --silent-debugger-extension-api
  

  To make it stick, always launch Chrome this way (e.g. a shell alias or a .command launcher) — a normal Dock click won't carry the flag.

  Trade-off: this weakens a security protection — any extension with the debugger permission can then silently attach without warning. Fine for personal use as long as you understand what it disables.

Development

npm install
npm start
npm run mcp
npm test

Load the local extension/ directory from chrome://extensions in Developer mode.

Security

• The extension uses Chrome's debugger permission. Install only versions you trust.
• The relay binds to 127.0.0.1 by default. Do not expose it to the public internet.
• Remote Relay never opens a port: the browser connects out to the public relay, which only holds a hash of your Device ID secret in memory. Treat the Device ID like a password; anyone with it can control the browser while Remote Relay is on.
• Browser Relay gives agents access to the same browser state you have, so treat enabled agents as trusted local software.

License

MIT