agent-browser CLI reference

Generic reference for the agent-browser CLI — automate Chromium-based apps (Electron, Chrome, web) via Chrome DevTools Protocol. This is the capture engine for all UI evidence in this skill. Per - 端 patterns live in ../surfaces/web.md and ../surfaces/electron.md; auth recipes in auth.md.

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.

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

bash

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 "[email protected]"
agent-browser fill @e2 "password123"
agent-browser click @e3
agent-browser wait --load networkidle
agent-browser snapshot -i # check result

Command chaining

bash

agent-browser open https://example.com && agent-browser wait --load networkidle && agent-browser snapshot -i

Use && when you don't need to read intermediate output. Run commands separately when you need to parse output first (e.g. snapshot to discover refs, then interact).

Essential commands

bash

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

# Snapshot
agent-browser snapshot -i             # Interactive elements with refs (recommended)
agent-browser snapshot -i -C          # Include contenteditable (rich text editors)
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 (NOT for contenteditable)
agent-browser type @e2 "text"         # Type without clearing (use for chat inputs)
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 scroll down 500         # Scroll page
agent-browser scroll down 500 --selector "div.content"  # Scroll within 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
agent-browser wait --text "Welcome"   # Wait for text to appear
agent-browser wait --fn "!document.body.innerText.includes('Loading...')"  # Wait for condition
agent-browser wait "#spinner" --state hidden  # Wait for element to disappear

# Network (key for full-stack evidence)
agent-browser network requests                 # Inspect tracked requests
agent-browser network requests --type xhr,fetch  # Filter by resource type
agent-browser network requests --method POST   # Filter by HTTP method
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
agent-browser set device "iPhone 14"          # Emulate device (viewport + UA)

# Capture (evidence!)
agent-browser screenshot ./shot.png   # Screenshot to a path
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

# Dialogs (alert, confirm, prompt, beforeunload)
agent-browser dialog accept           # Accept dialog
agent-browser dialog accept "input"   # Accept prompt dialog with text
agent-browser dialog dismiss          # Dismiss/cancel dialog
agent-browser dialog status           # Check if dialog is open

Batch execution

bash

echo '[
  ["open", "https://example.com"],
  ["snapshot", "-i"],
  ["click", "@e1"],
  ["screenshot", "result.png"]
]' | agent-browser batch --json

Semantic locators (alternative to refs)

bash

agent-browser find text "Sign In" click
agent-browser find label "Email" fill "[email protected]"
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 read app state, dump DOM/HTML, or assert computed values for text / dom_snapshot evidence.

bash

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

# Complex JS: use --stdin with heredoc (RECOMMENDED — avoids shell quoting bugs)
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

# Base64 encoding (avoids all shell escaping issues)
agent-browser eval -b "$(echo -n 'document.title' | base64)"

If the app under test exposes a global state object (a store, a debug handle), eval is how you read it for assertion. Don't assume a specific global name — discover it from the app you are verifying.

Ref lifecycle

Refs (@e1, @e2, …) are invalidated when the page changes. Always re-snapshot after clicking links/buttons that navigate, form submissions, or dynamic content loading. After a hot-reload (HMR) during dev, refs also break — re-snapshot.

Annotated screenshots (vision mode)

bash

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

Parallel sessions

bash

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

A named --session auto-saves and restores cookies + localStorage, which is the basis for the auth recipes in auth.md.

Connect to an existing browser / app

bash

agent-browser --auto-connect snapshot # Auto-discover a running Chrome
agent-browser --cdp 9222 snapshot     # Explicit CDP port (Electron apps, see ../surfaces/electron.md)

Cloud providers & engine selection

bash

agent-browser -p browserbase open example.com      # run against a cloud browser
agent-browser --engine lightpanda open example.com # 10x faster, 10x less memory

Providers: agentcore, browserbase, browserless, browseruse, kernel.

Gotchas

Daemon can get stuck — if commands hang, agent-browser close --all or pkill -f agent-browser to reset.
HMR invalidates everything — after code changes during dev, refs break; re-snapshot or restart.
snapshot -i doesn't find contenteditable — use snapshot -i -C for rich text editors; fill doesn't work on contenteditable, use type.
Screenshots written to a path are easiest — agent-browser screenshot ./proof/x.png then upload that path; with no path they land in ~/.agent-browser/tmp/screenshots/.
Dialogs block all commands — if commands time out, check agent-browser dialog status.
Default timeout is 25s — override with AGENT_BROWSER_DEFAULT_TIMEOUT (ms) or use explicit waits.
Shell quoting corrupts eval — use eval --stdin <<'EVALEOF' for complex JS.