agent-browser

name	agent-browser
description	Browser automation CLI for AI agents. Use when the user needs to interact with websites, including navigating pages, filling forms, clicking buttons, taking screenshots, extracting data, testing web apps, or automating any browser task. Triggers include requests to "open a website", "fill out a form", "click a button", "take a screenshot", "scrape data from a page", "test this web app", "login to a site", "automate browser actions", or any task requiring programmatic web interaction.
allowed-tools	bash
license	Apache-2.0
metadata	{"source":"https://github.com/vercel-labs/agent-browser","author":"vercel-labs","origin":"ported from agent-browser CLI documentation"}

Browser Automation with agent-browser

The CLI uses Chrome/Chromium via CDP directly. Install via npm i -g agent-browser, brew install agent-browser, or cargo install agent-browser. Run agent-browser install to download Chrome.

Core Workflow

Every browser automation follows this pattern:

1. Navigate: agent-browser open <url>
2. Snapshot: agent-browser snapshot -i (get element refs like @e1, @e2)
3. Interact: Use refs to click, fill, select
4. Re-snapshot: After navigation or DOM changes, get fresh refs

agent-browser open https://example.com/form
agent-browser snapshot -i
# Output: @e1 [input type="email"], @e2 [input type="password"], @e3 [button] "Submit"

agent-browser fill @e1 "[e-mail]"
agent-browser fill @e2 "password123"
agent-browser click @e3
agent-browser wait --load networkidle
agent-browser snapshot -i  # Check result

Command Chaining

Commands can be chained with && in a single shell invocation. The browser persists between commands via a background daemon, so chaining is safe and more efficient than separate calls.

# Chain open + wait + snapshot in one call
agent-browser open https://example.com && agent-browser wait --load networkidle && agent-browser snapshot -i

# Chain multiple interactions
agent-browser fill @e1 "[e-mail]" && agent-browser fill @e2 "password123" && agent-browser click @e3

# Navigate and capture
agent-browser open https://example.com && agent-browser wait --load networkidle && agent-browser screenshot page.png

When to chain: Use && when you don't need to read the output of an intermediate command before proceeding (e.g., open + wait + screenshot). Run commands separately when you need to parse the output first (e.g., snapshot to discover refs, then interact using those refs).

Handling Authentication

Choose the approach that fits. See references/authentication.md for full details including OAuth, 2FA, and token refresh.

Approach	When	Command
Auth vault	Recurring tasks, password never exposed to LLM	echo "$PW" | agent-browser auth save myapp --url <url> --username user --password-stdin then agent-browser auth login myapp
Session name	Auto-save/restore cookies across restarts	agent-browser --session-name myapp open <url>
Persistent profile	Full browser profile reuse	agent-browser --profile ~/.myapp open <url>
Import from user browser	One-off tasks, user already logged in	agent-browser --auto-connect state save ./auth.json then agent-browser --state ./auth.json open <url>
State file	Manual save/load	agent-browser state save auth.json / agent-browser state load auth.json

State files contain session tokens in plaintext -- add to .gitignore and set AGENT_BROWSER_ENCRYPTION_KEY for encryption at rest.

Essential Commands

For the full command reference with all options, see references/commands.md.

# Navigation
agent-browser open <url>              # Navigate (aliases: goto, navigate)
agent-browser close                   # Close browser

# Snapshot
agent-browser snapshot -i             # Interactive elements with refs (recommended)
agent-browser snapshot -i -C          # Include cursor-interactive elements
agent-browser snapshot -s "#selector" # Scope to CSS selector

# Interaction (use @refs from snapshot)
agent-browser click @e1               # Click element
agent-browser fill @e2 "text"         # Clear and type text
agent-browser type @e2 "text"         # Type without clearing
agent-browser select @e1 "option"     # Select dropdown option
agent-browser check @e1               # Check checkbox
agent-browser press Enter             # Press key
agent-browser scroll down 500         # Scroll page

# Get information
agent-browser get text @e1            # Get element text
agent-browser get url                 # Get current URL

# Wait
agent-browser wait @e1                # Wait for element
agent-browser wait --load networkidle # Wait for network idle
agent-browser wait --url "**/page"    # Wait for URL pattern
agent-browser wait --text "Welcome"   # Wait for text to appear
agent-browser wait "#spinner" --state hidden  # Wait for element to disappear

# Capture
agent-browser screenshot              # Screenshot to temp dir
agent-browser screenshot --full       # Full page screenshot
agent-browser screenshot --annotate   # Annotated with numbered element labels
agent-browser pdf output.pdf          # Save as PDF

# Diff (compare page states)
agent-browser diff snapshot           # Compare current vs last snapshot
agent-browser diff screenshot --baseline before.png  # Visual pixel diff

Common Patterns

Data Extraction

agent-browser open https://example.com/products
agent-browser snapshot -i
agent-browser get text @e5           # Get specific element text
agent-browser get text body > page.txt  # Get all page text

# JSON output for parsing
agent-browser snapshot -i --json
agent-browser get text @e1 --json

Parallel Sessions

agent-browser --session site1 open https://site-a.com
agent-browser --session site2 open https://site-b.com

agent-browser --session site1 snapshot -i
agent-browser --session site2 snapshot -i

agent-browser session list

Connect to Existing Chrome

# Auto-discover running Chrome with remote debugging enabled
agent-browser --auto-connect open https://example.com
agent-browser --auto-connect snapshot

# Or with explicit CDP port
agent-browser --cdp 9222 snapshot

Color Scheme (Dark Mode)

agent-browser --color-scheme dark open https://example.com    # Flag
AGENT_BROWSER_COLOR_SCHEME=dark agent-browser open https://example.com  # Env var
agent-browser set media dark                                  # During session

Viewport & Responsive Testing

agent-browser set viewport 1920 1080          # Desktop
agent-browser set viewport 375 812            # Mobile
agent-browser set viewport 1920 1080 2        # Retina (3rd arg = devicePixelRatio)
agent-browser set device "iPhone 14"          # Device emulation (viewport + UA)

Visual Browser (Debugging)

agent-browser --headed open https://example.com
agent-browser highlight @e1          # Highlight element
agent-browser inspect                # Open Chrome DevTools for the active page
agent-browser record start demo.webm # Record session
agent-browser profiler start         # Start Chrome DevTools profiling
agent-browser profiler stop trace.json # Stop and save profile (path optional)

Use AGENT_BROWSER_HEADED=1 to enable headed mode via environment variable. Browser extensions work in both headed and headless mode.

Local Files (PDFs, HTML)

# Open local files with file:// URLs
agent-browser --allow-file-access open file:///path/to/document.pdf
agent-browser --allow-file-access open file:///path/to/page.html
agent-browser screenshot output.png

iOS Simulator (Mobile Safari)

agent-browser -p ios --device "iPhone 16 Pro" open https://example.com
agent-browser -p ios snapshot -i && agent-browser -p ios tap @e1
agent-browser -p ios close

Requires macOS with Xcode and Appium (npm install -g appium && appium driver install xcuitest). Same workflow as desktop (snapshot, interact, re-snapshot). Use --device "<UDID>" for physical devices.

Security

All security features are opt-in. By default, agent-browser imposes no restrictions on navigation, actions, or output.

Content Boundaries (Recommended for AI Agents)

Enable --content-boundaries to wrap page-sourced output in markers that help LLMs distinguish tool output from untrusted page content:

export AGENT_BROWSER_CONTENT_BOUNDARIES=1
agent-browser snapshot
# Output:
# --- AGENT_BROWSER_PAGE_CONTENT nonce=<hex> origin=https://example.com ---
# [accessibility tree]
# --- END_AGENT_BROWSER_PAGE_CONTENT nonce=<hex> ---

Domain Allowlist

Restrict navigation to trusted domains. Wildcards like *.example.com also match the bare domain example.com. Sub-resource requests, WebSocket, and EventSource connections to non-allowed domains are also blocked. Include CDN domains your target pages depend on:

export AGENT_BROWSER_ALLOWED_DOMAINS="example.com,*.example.com"
agent-browser open https://example.com        # OK
agent-browser open https://malicious.com       # Blocked

Action Policy

Use a policy file to gate destructive actions:

export AGENT_BROWSER_ACTION_POLICY=./policy.json

Example policy.json:

{ "default": "deny", "allow": ["navigate", "snapshot", "click", "scroll", "wait", "get"] }

Auth vault operations (auth login, etc.) bypass action policy but domain allowlist still applies.

Output Limits

Prevent context flooding from large pages:

export AGENT_BROWSER_MAX_OUTPUT=50000

Diffing (Verifying Changes)

Use diff snapshot after performing an action to verify it had the intended effect. This compares the current accessibility tree against the last snapshot taken in the session.

# Typical workflow: snapshot -> action -> diff
agent-browser snapshot -i          # Take baseline snapshot
agent-browser click @e2            # Perform action
agent-browser diff snapshot        # See what changed (auto-compares to last snapshot)

For visual regression testing or monitoring:

# Save a baseline screenshot, then compare later
agent-browser screenshot baseline.png
# ... time passes or changes are made ...
agent-browser diff screenshot --baseline baseline.png

# Compare staging vs production
agent-browser diff url https://staging.example.com https://prod.example.com --screenshot

diff snapshot output uses + for additions and - for removals, similar to git diff. diff screenshot produces a diff image with changed pixels highlighted in red, plus a mismatch percentage.

Timeouts and Slow Pages

Default timeout is 25s (override with AGENT_BROWSER_DEFAULT_TIMEOUT in ms). For slow pages, use explicit waits after open:

agent-browser wait --load networkidle          # Best for slow pages
agent-browser wait "#content"                  # Wait for specific element
agent-browser wait --url "**/dashboard"        # Wait for URL pattern (after redirects)
agent-browser wait --fn "document.readyState === 'complete'"  # JS condition
agent-browser wait 5000                        # Fixed delay (last resort)

Session Management and Cleanup

Use named sessions for concurrent automations. Always close sessions when done to avoid leaked processes:

agent-browser --session agent1 open site-a.com
agent-browser --session agent2 open site-b.com
agent-browser session list                         # Check active sessions
agent-browser --session agent1 close               # Close specific session
agent-browser close                                # Close default session
AGENT_BROWSER_IDLE_TIMEOUT_MS=60000 agent-browser open example.com  # Auto-shutdown after inactivity

If a previous session was not closed properly, run agent-browser close to clean up the daemon.

Ref Lifecycle (Important)

Refs (@e1, @e2, etc.) are invalidated when the page changes. Always re-snapshot after:

• Clicking links or buttons that navigate
• Form submissions
• Dynamic content loading (dropdowns, modals)

agent-browser click @e5              # Navigates to new page
agent-browser snapshot -i            # MUST re-snapshot
agent-browser click @e1              # Use new refs

Annotated Screenshots (Vision Mode)

Use --annotate to take a screenshot with numbered labels overlaid on interactive elements. Each label [N] maps to ref @eN. This also caches refs, so you can interact with elements immediately without a separate snapshot.

agent-browser screenshot --annotate
# Output includes the image path and a legend:
#   [1] @e1 button "Submit"
#   [2] @e2 link "Home"
#   [3] @e3 textbox "Email"
agent-browser click @e2              # Click using ref from annotated screenshot

Use annotated screenshots when:

• The page has unlabeled icon buttons or visual-only elements
• You need to verify visual layout or styling
• Canvas or chart elements are present (invisible to text snapshots)
• You need spatial reasoning about element positions

Semantic Locators (Alternative to Refs)

When refs are unavailable or unreliable, use semantic locators:

agent-browser find text "Sign In" click
agent-browser find label "Email" fill "[e-mail]"
agent-browser find role button click --name "Submit"
agent-browser find placeholder "Search" type "query"
agent-browser find testid "submit-btn" click

JavaScript Evaluation (eval)

Use --stdin with heredoc for anything beyond simple expressions (avoids shell quoting issues):

# Simple expressions
agent-browser eval 'document.title'

# Complex JS (recommended approach for nested quotes, arrow functions, multiline)
agent-browser eval --stdin <<'EVALEOF'
JSON.stringify(
  Array.from(document.querySelectorAll("img"))
    .filter(i => !i.alt)
    .map(i => ({ src: i.src.split("/").pop(), width: i.width }))
)
EVALEOF

# Programmatic/generated scripts: base64 encoding
agent-browser eval -b "$(echo -n 'Array.from(document.querySelectorAll("a")).map(a => a.href)' | base64)"

Configuration File

Create agent-browser.json in the project root for persistent settings. All CLI options map to camelCase keys (e.g., --executable-path -> "executablePath"). Priority: ~/.agent-browser/config.json < ./agent-browser.json < env vars < CLI flags.

Deep-Dive Documentation

Reference	When to Use
references/commands.md	Full command reference with all options
references/snapshot-refs.md	Ref lifecycle, invalidation rules, troubleshooting
references/session-management.md	Parallel sessions, state persistence, concurrent scraping
references/authentication.md	Login flows, OAuth, 2FA handling, state reuse
references/video-recording.md	Recording workflows for debugging and documentation
references/profiling.md	Chrome DevTools profiling for performance analysis
references/proxy-support.md	Proxy configuration, geo-testing, rotating proxies

Browser Engine Selection

Default engine is chrome. Use --engine lightpanda for 10x faster headless browsing (does not support --extension, --profile, --state, or --allow-file-access):

agent-browser --engine lightpanda open example.com