Firefox Browser

Firefox Browser Agent Bridge

Control the user's actual Firefox browser session via WebSocket. This uses their real browser with existing logins and cookies - not a headless browser.

Quick Start

# 0. If Firefox isn't running, start it first
nohup firefox &>/dev/null &

# 1. Check connection
browser ping

# 2. See what tabs are open
browser listTabs '{}'

# 3. Start a new session (recommended)
browser newSession '{"url": "https://example.com"}'

# 4. Read the page with interactable elements marked
browser getContent '{"format": "annotated"}'

Client Usage

browser <action> '<json_params>'

Actions Reference

Session & Tab Management

Navigation & Page Info

Interaction

fillForm - The Right Way to Fill Forms

IMPORTANT: There is no fill command. Use fillForm with a fields array:

# Fill a single field
browser fillForm '{"fields": [{"selector": "#email", "value": "test@example.com"}]}'

# Fill multiple fields at once (text inputs, textareas, AND select dropdowns)
browser fillForm '{"fields": [
  {"selector": "#name", "value": "John Doe"},
  {"selector": "#email", "value": "john@example.com"},
  {"selector": "#subject", "value": "support"},
  {"selector": "#message", "value": "Hello world"}
]}'

Works with: <input>, <textarea>, <select>, checkboxes, radio buttons.

Control Flow

Authentication

Recommended Workflow

1. Start by Inspecting Available Tabs

browser listTabs '{}'

Returns:

{
  "activeTabId": 123,
  "windows": [
    {
      "windowId": 1,
      "focused": true,
      "tabs": [
        {"tabId": 123, "url": "https://...", "title": "...", "active": true}
      ]
    }
  ],
  "totalTabs": 5
}

2. Start Fresh or Pick Existing Tab

# Start fresh
browser newSession '{"url": "https://amazon.com"}'

# Or switch to existing tab
browser setActiveTab '{"tabId": 456}'

3. Read Page with Annotated Format (Recommended)

browser getContent '{"format": "annotated"}'

Returns content with interactive elements marked inline:

Product Name Here
$4.99
[button: "Add to cart" | selector: #add-btn]
[input:text: "search" | value: "" | selector: #search-box]
[link: "View details" | href: /product/123 | selector: a.details-link]

This shows what's clickable and where it is in context.

4. Interact Using Selectors

# Click using selector from annotated output
browser click '{"selector": "#add-btn"}'

# Or by text (prefers visible elements)
browser click '{"text": "Add to cart"}'

# Type into input
browser type '{"selector": "#search-box", "text": "query", "submit": true}'

Fork: Speculative Parallel Execution

When you're not sure which path is right, fork the tab and try both:

# Create forks
browser fork '{
  "paths": [
    {
      "name": "google-auth",
      "commands": [{"action": "click", "params": {"text": "Sign in with Google"}}]
    },
    {
      "name": "email-auth",
      "commands": [{"action": "click", "params": {"text": "Sign in with Email"}}]
    }
  ]
}'

Returns:

{
  "forked": true,
  "sourceTabId": 123,
  "forks": [
    {"name": "google-auth", "tabId": 456, "url": "...", "commandResults": [...]},
    {"name": "email-auth", "tabId": 789, "url": "...", "commandResults": [...]}
  ]
}

Work on specific fork:

browser getContent '{"format": "annotated", "fork": "google-auth"}'
browser click '{"text": "Continue", "fork": "google-auth"}'

Kill the wrong path:

browser killFork '{"fork": "email-auth"}'

TryUntil: Handle Uncertain UI

When the exact button varies (cookie banners, A/B tests):

browser tryUntil '{
  "alternatives": [
    {"action": "click", "params": {"selector": "#accept-cookies"}},
    {"action": "click", "params": {"text": "Accept All"}},
    {"action": "click", "params": {"selector": ".cookie-dismiss"}}
  ],
  "timeout": 3000
}'

Tries each until one succeeds.

Parallel: Multiple URLs at Once

Compare prices across sites:

browser parallel '{
  "branches": [
    {"url": "https://amazon.com/product", "commands": [{"action": "getContent", "params": {"format": "text"}}]},
    {"url": "https://walmart.com/product", "commands": [{"action": "getContent", "params": {"format": "text"}}]}
  ]
}'

Authentication

The bridge detects auth pages and leverages existing browser sessions:

# Check if on login page
browser getAuthContext '{}'

# Returns available accounts, OAuth options, etc.

Isolated Sessions (for Parallel Execution)

When running multiple tasks in parallel, use tabId to avoid conflicts:

# 1. Create isolated session - get a unique tabId
browser newSession '{"url": "https://example.com"}'
# Returns: {"tabId": 15, "url": "...", "windowId": 1}

# 2. Use that tabId in ALL subsequent commands
browser navigate '{"url": "https://example.com/page", "tabId": 15}'
browser getContent '{"format": "annotated", "tabId": 15}'
browser click '{"selector": "#btn", "tabId": 15}'
browser type '{"selector": "#input", "text": "hello", "tabId": 15}'

This lets multiple agents work in parallel without stepping on each other.

Tips

1. Start with listTabs to see what's open
2. Use newSession for a clean start
3. Use tabId for parallel/isolated execution
4. Use annotated format - shows content + clickable elements together
5. Use selectors from annotated output - more reliable than text matching
6. Fork when uncertain - try multiple paths, kill the wrong ones

Troubleshooting

1. Firefox not running? Start it: nohup firefox &>/dev/null &
2. Check connection: browser ping
3. Connection refused? The extension may need to be reloaded in about:debugging
4. Element not found? Use browser getContent '{"format": "annotated"}' to see what's on the page