Browser Tool
Some systems have no API. The web UI is the only door. Treat it as a last-resort tool.
A intern with a laptop — they can use the site, they can also click Delete.
Visual Workflows
Start here — scroll inside each diagram frame to explore, then use + / − to zoom up to 200% if needed.
Overview
Scroll inside the frame to explore · use + / − to zoom up to 200%
Scroll inside the frame to explore · use + / − to zoom up to 200%
Extract, do not dump
Scroll inside the frame to explore · use + / − to zoom up to 200%
Navigate, then return the field you need.
Key Takeaways
- 1.A browser tool lets the agent click, type, and read pages. It is slow, brittle, and powerful — use APIs when they exist.
- 2.Sandbox the browser: allowlist hosts, no file downloads to prod disks. Prefer structured extract over dumping the whole DOM.
- 3.Playwright/Puppeteer in a sandbox. Allowlist domains.
- 4.Cap step count. Return extracted text or screenshots, not 2MB of HTML.
- 5.HITL for logins and purchases.
Learn elsewhere
- →Browser agents — Phase 23
- →Tool Permissions
Real Example
Scenario
Vendor portal has no API. Browser tool opens the invoice page and returns due date + amount. It cannot visit arbitrary URLs.
What you would do
In Tool Calling & Function Calling, apply Browser Tool to this scenario: Vendor portal has no API. Identify the inputs, run the technique, validate the output, and note one thing you would monitor in production.
Commands
Commands to Remember
Last resort vs an APIAllowlist hostsExtract fieldsHITL for money and login
Cheat Sheet
Quick recap
quick ref- •UI when there is no API
- •Slow and brittle
- •Sandbox + allowlist
- •Do not dump the DOM
Common Mistakes
- ✕Giving the agent the whole internet
- ✕Pasting full HTML into the context window
- ✕No timeout on page.goto