Agent Browser

Use a controlled browser to verify behavior, capture evidence, or extract information from web pages that a static fetch cannot reach (SPAs, login-gated pages, dynamic content). This skill is about supervised verification, not unattended scraping.

When to use

• You need a screenshot of a deployed page or a local dev server to confirm a UI change.
• You need to read JavaScript-rendered content that curl/wget will not see.
• A user reports a UI bug and you need to reproduce it interactively to capture console errors, network requests, or layout state.
• You need to walk through a short flow (load page, click, observe) to verify acceptance criteria.

When not to use

• The page is reachable as static HTML. Use curl/HTTP fetch, it is cheaper, faster, and more reliable.
• The task is unattended large-scale scraping. That belongs to a dedicated scraper with rate limits, robots.txt handling, and a real user agent policy, not this skill.
• The site is behind authentication you do not own credentials for, or whose terms of service prohibit automation.
• The site involves sensitive accounts (banking, healthcare, government) where automation risks lockout or compliance issues.

Before launching the browser

• Confirm the URL and what state should be true after navigation.
• Decide what evidence is needed: full-page screenshot, viewport screenshot, console log, network trace, HTML snapshot, extracted text.
• Decide the viewport size that matters for the task (mobile vs desktop). Default to a desktop size unless the task is mobile-specific.
• For local dev servers, confirm the server is running and the port is what you expect.

Driving the browser

A typical verification session: