Browser automation CLI for AI agents. Use when the user needs to interact with websites, verify dev server output, test web apps, navigate pages, fill forms, click buttons, take screenshots, extract data, or automate any browser task. Also triggers when a dev server starts so you can verify it visually.
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name
agent-browser
description
Browser automation CLI for AI agents. Use when the user needs to interact with websites, verify dev server output, test web apps, navigate pages, fill forms, click buttons, take screenshots, extract data, or automate any browser task. Also triggers when a dev server starts so you can verify it visually.
{"aliases":["browser automation","puppeteer","playwright","web scraping"],"intents":["automate browser","take screenshot","test web app","fill form","click button"],"entities":["Puppeteer","Playwright","screenshot","browser","headless"]}
chainTo
[{"pattern":"localhost:\\d+|127\\.0\\.0\\.1:\\d+","targetSkill":"agent-browser-verify","message":"Dev server URL detected — loading browser verification skill to run a visual gut-check (page loads, console errors, key UI elements)."},{"pattern":"playwright\\.config|cypress\\.config|\\.spec\\.(ts|js)|\\.test\\.(ts|js).*browser","targetSkill":"nextjs","message":"End-to-end test configuration detected — loading Next.js guidance for framework-aware test setup and dev server integration."}]
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. Run agent-browser upgrade to update to the latest version.
Core Workflow
Every browser automation follows this pattern:
Navigate: agent-browser open <url>
Snapshot: agent-browser snapshot -i (get element refs like @e1, @e2)
Interact: Use refs to click, fill, select
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 "user@example.com"
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 "user@example.com" && 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
When automating a site that requires login, choose the approach that fits:
Option 1: Import auth from the user's browser (fastest for one-off tasks)
# Connect to the user's running Chrome (they're already logged in)
agent-browser --auto-connect state save ./auth.json
# Use that auth state
agent-browser --state ./auth.json open https://app.example.com/dashboard
State files contain session tokens in plaintext -- add to .gitignore and delete when no longer needed. Set AGENT_BROWSER_ENCRYPTION_KEY for encryption at rest.
Option 2: Persistent profile (simplest for recurring tasks)
# First run: login manually or via automation
agent-browser --profile ~/.myapp open https://app.example.com/login
# ... fill credentials, submit ...# All future runs: already authenticated
agent-browser --profile ~/.myapp open https://app.example.com/dashboard
Option 3: Session name (auto-save/restore cookies + localStorage)
agent-browser --session-name myapp open https://app.example.com/login
# ... login flow ...
agent-browser close # State auto-saved# Next time: state auto-restored
agent-browser --session-name myapp open https://app.example.com/dashboard
Option 4: Auth vault (credentials stored encrypted, login by name)
echo"$PASSWORD" | agent-browser auth save myapp --url https://app.example.com/login --username user --password-stdin
agent-browser auth login myapp
auth login navigates with load and then waits for login form selectors to appear before filling/clicking, which is more reliable on delayed SPA login screens.
Option 5: State file (manual save/load)
# After logging in:
agent-browser state save ./auth.json
# In a future session:
agent-browser state load ./auth.json
agent-browser open https://app.example.com/dashboard
# 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 (divs with onclick, cursor:pointer)
agent-browser snapshot -s "#selector"# Scope to CSS selector# Interaction (use @refs from snapshot)
agent-browser click @e1 # Click element
agent-browser click @e1 --new-tab # Click and open in new tab
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 keyboard type"text"# Type at current focus (no selector)
agent-browser keyboard inserttext "text"# Insert without key events
agent-browser scroll down 500 # Scroll page
agent-browser scroll down 500 --selector "div.content"# Scroll within a specific container# Get information
agent-browser get text @e1 # Get element text
agent-browser get url # Get current URL
agent-browser get title # Get page title
agent-browser get cdp-url # Get CDP WebSocket 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 2000 # Wait milliseconds
agent-browser wait --text "Welcome"# Wait for text to appear (substring match)
agent-browser wait --fn "!document.body.innerText.includes('Loading...')"# Wait for text to disappear
agent-browser wait"#spinner" --state hidden # Wait for element to disappear# Downloads
agent-browser download @e1 ./file.pdf # Click element to trigger download
agent-browser wait --download ./output.zip # Wait for any download to complete
agent-browser --download-path ./downloads open <url> # Set default download directory# Network
agent-browser network requests # Inspect tracked requests
agent-browser network route "**/api/*" --abort # Block matching requests
agent-browser network har start # Start HAR recording
agent-browser network har stop ./capture.har # Stop and save HAR file# Viewport & Device Emulation
agent-browser set viewport 1920 1080 # Set viewport size (default: 1280x720)
agent-browser set viewport 1920 1080 2 # 2x retina (same CSS size, higher res screenshots)
agent-browser set device "iPhone 14"# Emulate device (viewport + user agent)# Capture
agent-browser screenshot # Screenshot to temp dir
agent-browser screenshot --full # Full page screenshot
agent-browser screenshot --annotate # Annotated screenshot with numbered element labels
agent-browser screenshot --screenshot-dir ./shots # Save to custom directory
agent-browser screenshot --screenshot-format jpeg --screenshot-quality 80
agent-browser pdf output.pdf # Save as PDF# Clipboard
agent-browser clipboard read# Read text from clipboard
agent-browser clipboard write "Hello, World!"# Write text to clipboard
agent-browser clipboard copy # Copy current selection
agent-browser clipboard paste# Paste from clipboard# Diff (compare page states)
agent-browser diff snapshot # Compare current vs last snapshot
agent-browser diff snapshot --baseline before.txt # Compare current vs saved file
agent-browser diff screenshot --baseline before.png # Visual pixel diff
agent-browser diff url <url1> <url2> # Compare two pages
agent-browser diff url <url1> <url2> --wait-until networkidle # Custom wait strategy
agent-browser diff url <url1> <url2> --selector "#main"# Scope to element
Batch Execution
Execute multiple commands in a single invocation by piping a JSON array of string arrays to batch. This avoids per-command process startup overhead when running multi-step workflows.
Use batch when you have a known sequence of commands that don't depend on intermediate output. Use separate commands or && chaining when you need to parse output between steps (e.g., snapshot to discover refs, then interact).
Common Patterns
Form Submission
agent-browser open https://example.com/signup
agent-browser snapshot -i
agent-browser fill @e1 "Jane Doe"
agent-browser fill @e2 "jane@example.com"
agent-browser select @e3 "California"
agent-browser check @e4
agent-browser click @e5
agent-browser wait --load networkidle
Authentication with Auth Vault (Recommended)
# Save credentials once (encrypted with AGENT_BROWSER_ENCRYPTION_KEY)# Recommended: pipe password via stdin to avoid shell history exposureecho"pass" | agent-browser auth save github --url https://github.com/login --username user --password-stdin
# Login using saved profile (LLM never sees password)
agent-browser auth login github
# List/show/delete profiles
agent-browser auth list
agent-browser auth show github
agent-browser auth delete github
auth login waits for username/password/submit selectors before interacting, with a timeout tied to the default action timeout.
Authentication with State Persistence
# Login once and save state
agent-browser open https://app.example.com/login
agent-browser snapshot -i
agent-browser fill @e1 "$USERNAME"
agent-browser fill @e2 "$PASSWORD"
agent-browser click @e3
agent-browser wait --url "**/dashboard"
agent-browser state save auth.json
# Reuse in future sessions
agent-browser state load auth.json
agent-browser open https://app.example.com/dashboard
Session Persistence
# Auto-save/restore cookies and localStorage across browser restarts
agent-browser --session-name myapp open https://app.example.com/login
# ... login flow ...
agent-browser close # State auto-saved to ~/.agent-browser/sessions/# Next time, state is auto-loaded
agent-browser --session-name myapp open https://app.example.com/dashboard
# Encrypt state at restexport AGENT_BROWSER_ENCRYPTION_KEY=$(openssl rand -hex 32)
agent-browser --session-name secure open https://app.example.com
# Manage saved states
agent-browser state list
agent-browser state show myapp-default.json
agent-browser state clear myapp
agent-browser state clean --older-than 7
Working with Iframes
Iframe content is automatically inlined in snapshots. Refs inside iframes carry frame context, so you can interact with them directly.
agent-browser open https://example.com/checkout
agent-browser snapshot -i
# @e1 [heading] "Checkout"# @e2 [Iframe] "payment-frame"# @e3 [input] "Card number"# @e4 [input] "Expiry"# @e5 [button] "Pay"# Interact directly — no frame switch needed
agent-browser fill @e3 "4111111111111111"
agent-browser fill @e4 "12/28"
agent-browser click @e5
# To scope a snapshot to one iframe:
agent-browser frame @e2
agent-browser snapshot -i # Only iframe content
agent-browser frame main # Return to main frame
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
Auto-connect discovers Chrome via DevToolsActivePort, common debugging ports (9222, 9229), and falls back to a direct WebSocket connection if HTTP-based CDP discovery fails.
Color Scheme (Dark Mode)
# Persistent dark mode via flag (applies to all pages and new tabs)
agent-browser --color-scheme dark open https://example.com
# Or via environment variable
AGENT_BROWSER_COLOR_SCHEME=dark agent-browser open https://example.com
# Or set during session (persists for subsequent commands)
agent-browser set media dark
Viewport & Responsive Testing
# Set a custom viewport size (default is 1280x720)
agent-browser set viewport 1920 1080
agent-browser screenshot desktop.png
# Test mobile-width layout
agent-browser set viewport 375 812
agent-browser screenshot mobile.png
# Retina/HiDPI: same CSS layout at 2x pixel density# Screenshots stay at logical viewport size, but content renders at higher DPI
agent-browser set viewport 1920 1080 2
agent-browser screenshot retina.png
# Device emulation (sets viewport + user agent in one step)
agent-browser set device "iPhone 14"
agent-browser screenshot device.png
The scale parameter (3rd argument) sets window.devicePixelRatio without changing CSS layout. Use it when testing retina rendering or capturing higher-resolution screenshots.
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)
# List available iOS simulators
agent-browser device list
# Launch Safari on a specific device
agent-browser -p ios --device "iPhone 16 Pro" open https://example.com
# Same workflow as desktop - snapshot, interact, re-snapshot
agent-browser -p ios snapshot -i
agent-browser -p ios tap @e1 # Tap (alias for click)
agent-browser -p ios fill @e2 "text"
agent-browser -p ios swipe up # Mobile-specific gesture# Take screenshot
agent-browser -p ios screenshot mobile.png
# Close session (shuts down simulator)
agent-browser -p ios close
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
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
The default timeout is 25 seconds. This can be overridden with the AGENT_BROWSER_DEFAULT_TIMEOUT environment variable (value in milliseconds). For slow websites or large pages, use explicit waits instead of relying on the default timeout:
# Wait for network activity to settle (best for slow pages)
agent-browser wait --load networkidle
# Wait for a specific element to appear
agent-browser wait"#content"
agent-browser wait @e1
# Wait for a specific URL pattern (useful after redirects)
agent-browser wait --url "**/dashboard"# Wait for a JavaScript condition
agent-browser wait --fn "document.readyState === 'complete'"# Wait a fixed duration (milliseconds) as a last resort
agent-browser wait 5000
When dealing with consistently slow websites, use wait --load networkidle after open to ensure the page is fully loaded before taking a snapshot. If a specific element is slow to render, wait for it directly with wait <selector> or wait @ref.
Session Management and Cleanup
When running multiple agents or automations concurrently, always use named sessions to avoid conflicts:
# Each agent gets its own isolated session
agent-browser --session agent1 open site-a.com
agent-browser --session agent2 open site-b.com
# Check active sessions
agent-browser session list
Always close your browser session when done to avoid leaked processes:
agent-browser close # Close default session
agent-browser --session agent1 close # Close specific session
If a previous session was not closed properly, the daemon may still be running. Use agent-browser close to clean it up before starting new work.
To auto-shutdown the daemon after a period of inactivity (useful for ephemeral/CI environments):
AGENT_BROWSER_IDLE_TIMEOUT_MS=60000 agent-browser open example.com
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 "user@test.com"
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 eval to run JavaScript in the browser context. Shell quoting can corrupt complex expressions -- use --stdin or -b to avoid issues.
Why this matters: When the shell processes your command, inner double quotes, ! characters (history expansion), backticks, and $() can all corrupt the JavaScript before it reaches agent-browser. The --stdin and -b flags bypass shell interpretation entirely.
Rules of thumb:
Single-line, no nested quotes -> regular eval 'expression' with single quotes is fine
Nested quotes, arrow functions, template literals, or multiline -> use eval --stdin <<'EVALEOF'
Programmatic/generated scripts -> use eval -b with base64
Configuration File
Create agent-browser.json in the project root for persistent settings:
Priority (lowest to highest): ~/.agent-browser/config.json < ./agent-browser.json < env vars < CLI flags. Use --config <path> or AGENT_BROWSER_CONFIG env var for a custom config file (exits with error if missing/invalid). All CLI options map to camelCase keys (e.g., --executable-path -> "executablePath"). Boolean flags accept true/false values (e.g., --headed false overrides config). Extensions from user and project configs are merged, not replaced.
Use --engine to choose a local browser engine. The default is chrome.
# Use Lightpanda (fast headless browser, requires separate install)
agent-browser --engine lightpanda open example.com
# Via environment variableexport AGENT_BROWSER_ENGINE=lightpanda
agent-browser open example.com
# With custom binary path
agent-browser --engine lightpanda --executable-path /path/to/lightpanda open example.com
Supported engines:
chrome (default) -- Chrome/Chromium via CDP
lightpanda -- Lightpanda headless browser via CDP (10x faster, 10x less memory than Chrome)
