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.

Setup Check

Check installation

command -v agent-browser >/dev/null 2>&1 && echo "Installed" || echo "NOT INSTALLED - run: npm install -g agent-browser && agent-browser install"

Install if needed

npm install -g agent-browser agent-browser install # Downloads Chromium

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

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

See references/authentication.md for OAuth, 2FA, cookie-based auth, and token refresh patterns.

Essential Commands

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

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

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 exposure

echo "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

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 rest

export 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

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)

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

Requirements: macOS with Xcode, Appium (npm install -g appium && appium driver install xcuitest )

Real devices: Works with physical iOS devices if pre-configured. Use --device "<UDID>" where UDID is from xcrun xctrace list 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

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.

Simple expressions work with regular quoting

agent-browser eval 'document.title' agent-browser eval 'document.querySelectorAll("img").length'

Complex JS: use --stdin with heredoc (RECOMMENDED)

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

Alternative: base64 encoding (avoids all shell escaping issues)

agent-browser eval -b "$(echo -n 'Array.from(document.querySelectorAll("a")).map(a => a.href)' | base64)"

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:

{ "headed": true, "proxy": "http://localhost:8080", "profile": "./browser-data" }

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.

Browser Engine Selection

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 variable

export 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)

Lightpanda does not support --extension , --profile , --state , or --allow-file-access . Install Lightpanda from https://lightpanda.io/docs/open-source/installation.

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

Ready-to-Use Templates

Template Description

templates/form-automation.sh Form filling with validation

templates/authenticated-session.sh Login once, reuse state

templates/capture-workflow.sh Content extraction with screenshots

./templates/form-automation.sh https://example.com/form ./templates/authenticated-session.sh https://app.example.com/login ./templates/capture-workflow.sh https://example.com ./output

vs Playwright MCP

Feature agent-browser (CLI) Playwright MCP

Interface Bash commands MCP tools

Selection Refs (@e1) Refs (e1)

Output Text/JSON Tool responses

Parallel Sessions Tabs

Best for Quick automation Tool integration

Use agent-browser when:

• You prefer Bash-based workflows

• You want simpler CLI commands

• You need quick one-off automation

Use Playwright MCP when:

• You need deep MCP tool integration

• You want tool-based responses

• You're building complex automation