- 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:
- Navigate
- :
- agent-browser open
- 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 < url 1
< url 2
Compare two pages
agent-browser diff url < url 1
< url 2
--wait-until networkidle
Custom wait strategy
agent-browser diff url < url 1
< url 2
--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 "
Output:
--- AGENT_BROWSER_PAGE_CONTENT nonce= origin=https://example.com ---
[accessibility tree]
--- END_AGENT_BROWSER_PAGE_CONTENT nonce= ---
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
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
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 . 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