Agent Browser

---
name: agent-browser
description: "Browser automation CLI for AI agents. Use for website interaction, form automation, screenshots, scraping, and web app verification. Prefer snapshot refs (@e1, @e2) for deterministic actions."
allowed-tools: Read Write Bash Grep Glob
metadata:
  tags: browser-automation, headless-browser, ai-agent, web-testing, web-scraping, verification
  platforms: Claude, Gemini, Codex, ChatGPT
  version: 1.1.0
  source: vercel-labs/agent-browser
---


# agent-browser - Browser Automation for AI Agents

## When to use this skill

- Open websites and automate UI actions
- Fill forms, click controls, and verify outcomes
- Capture screenshots/PDFs or extract content
- Run deterministic web checks with accessibility refs
- Execute parallel browser tasks via isolated sessions

## Core workflow

Always use the deterministic ref loop:

1. `agent-browser open <url>`
2. `agent-browser snapshot -i`
3. interact with refs (`@e1`, `@e2`, ...)
4. `agent-browser snapshot -i` again after page/DOM changes

```bash
agent-browser open https://example.com/form
agent-browser wait --load networkidle
agent-browser snapshot -i
agent-browser fill @e1 "user@example.com"
agent-browser click @e2
agent-browser snapshot -i
```

## Command patterns

Use `&&` chaining when intermediate output is not needed.

```bash
# Good chaining: open -> wait -> snapshot
agent-browser open https://example.com && agent-browser wait --load networkidle && agent-browser snapshot -i

# Separate calls when output is needed first
agent-browser snapshot -i
# parse refs
agent-browser click @e2
```

High-value commands:
- Navigation: `open`, `close`
- Snapshot: `snapshot -i`, `snapshot -i -C`, `snapshot -s "#selector"`
- Interaction: `click`, `fill`, `type`, `select`, `check`, `press`
- Verification: `diff snapshot`, `diff screenshot --baseline <file>`
- Capture: `screenshot`, `screenshot --annotate`, `pdf`
- Wait: `wait --load networkidle`, `wait <selector|@ref|ms>`

## Verification patterns

Use explicit evidence after actions.

```bash
# Baseline -> action -> verify structure
agent-browser snapshot -i
agent-browser click @e3
agent-browser diff snapshot

# Visual regression
agent-browser screenshot baseline.png
agent-browser click @e5
agent-browser diff screenshot --baseline baseline.png
```

## Safety and reliability

- Refs are invalid after navigation or significant DOM updates; re-snapshot before next action.
- Prefer `wait --load networkidle` or selector/ref waits over fixed sleeps.
- For multi-step JS, use `eval --stdin` (or base64) to avoid shell escaping breakage.
- For concurrent tasks, isolate with `--session <name>`.
- Use output controls in long pages to reduce context flooding.
- Optional hardening in sensitive flows: domain allowlist and action policies.

Optional hardening examples:

```bash
# Wrap page content with boundaries to reduce prompt-injection risk
export AGENT_BROWSER_CONTENT_BOUNDARIES=1

# Limit output volume for long pages
export AGENT_BROWSER_MAX_OUTPUT=50000

# Restrict navigation and network to trusted domains
export AGENT_BROWSER_ALLOWED_DOMAINS="example.com,*.example.com"

# Restrict allowed action types
export AGENT_BROWSER_ACTION_POLICY=./policy.json
```

Example `policy.json`:

```json
{"default":"deny","allow":["navigate","snapshot","click","fill","scroll","wait","get"],"deny":["eval","download","upload","network","state"]}
```

CLI-flag equivalent:

```bash
agent-browser --content-boundaries --max-output 50000 --allowed-domains "example.com,*.example.com" --action-policy ./policy.json open https://example.com
```

## Troubleshooting

- `command not found`: install and run `agent-browser install`.
- Wrong element clicked: run `snapshot -i` again and use fresh refs.
- Dynamic SPA content missing: wait with `--load networkidle` or targeted `wait` selector.
- Session collisions: assign unique `--session` names and close each session.
- Large output pressure: narrow snapshots (`-i`, `-c`, `-d`, `-s`) and extract only needed text.

## References

Deep-dive docs in this skill:
- [commands](./references/commands.md)
- [snapshot-refs](./references/snapshot-refs.md)
- [session-management](./references/session-management.md)
- [authentication](./references/authentication.md)

Related resources:
- https://github.com/vercel-labs/agent-browser
- https://agent-browser.dev

Ready templates:
- `./templates/form-automation.sh`
- `./templates/capture-workflow.sh`

## Metadata

- Version: 1.1.0
- Last updated: 2026-02-26
- Scope: deterministic browser automation for agent workflows