Browser Automation with agent-browser

Required lifecycle (must follow)

Define agent-browser once per shell:

agent-browser(){ nix run github:numtide/llm-agents.nix#agent-browser -- "$@"; }

Then use agent-browser <command> everywhere below.

Hard rules:

• Before each new task, run agent-browser close once to clear stale sessions.

• End every task with agent-browser close , even when a command fails.

• If interrupted or unsure about state, run agent-browser close immediately, then restart from open .

Auth check policy: do not infer missing auth from absent environment variables alone. agent-browser may authenticate via its auth vault, saved browser state, or an existing session. Verify with real commands like agent-browser auth list , agent-browser state list , or the actual login flow.

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).

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

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

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

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 pdf output.pdf # Save as PDF

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

Visual Browser (Debugging)

agent-browser --headed open https://example.com agent-browser highlight @e1 # Highlight element 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 .

Advanced Workflows

Use the advanced reference when you need:

• content boundaries, allowlists, action policy, or output limits

• snapshot/screenshot diffing and regression checks

• timeout strategy for slow pages

• ref invalidation / re-snapshot rules

• semantic locators or eval usage

• persistent config file behavior

See references/advanced.md.

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

references/advanced.md Security controls, diffing, timeouts, eval , config, ref lifecycle

Experimental: Native Mode

agent-browser has an experimental native Rust daemon that communicates with Chrome directly via CDP, bypassing Node.js and Playwright entirely. It is opt-in and not recommended for production use yet.

Enable via flag

agent-browser --native open example.com

Enable via environment variable (avoids passing --native every time)

export AGENT_BROWSER_NATIVE=1 agent-browser open example.com

The native daemon supports Chromium and Safari (via WebDriver). Firefox and WebKit are not yet supported. All core commands (navigate, snapshot, click, fill, screenshot, cookies, storage, tabs, eval, etc.) work identically in native mode. Use agent-browser close before switching between native and default mode within the same session.

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