We Built the Browser AI Agents Can Pay For

Every hosted browser product we could find bills the same way: browser-hours, sessions, subscriptions. That works when a human with a credit card is in the loop. It does not work for the caller that is becoming normal — an autonomous agent with a wallet, a task, and no account anywhere.

So we shipped the missing shape. Agent Browser is a real Chromium browser exposed as an MCP server, and on the hosted endpoint every action is priced in USDC on Base via x402:

Discovery (initialize, tools/list) is free. A paid tools/call gets a standard HTTP 402 challenge with Bazaar discovery metadata; pay and retry — no signup, no API key, no dashboard. We measured the only other interactive browser selling single calls over x402 at $0.10 flat per call (October 2026). Every Agent Browser action is 5–20× under that, and a 20-action research task costs about $0.15, quoted before the first call is made.

Two doors, one codebase

The same server also runs over stdio, free, on your own machine:

claude mcp add agent-browser npx -y @scriptmasterlabs/agent-browser

That is deliberate. The local door is the adoption funnel — an agent that already knows these six tools from its own machine is the hosted door's future customer. Same tool names, same schemas, same error codes on both doors. The npm package is in the publish queue; until it lands, the hosted endpoint and the source are the way in.

Two design choices are worth stealing if you build in this category:

Snapshots over screenshots. browser_snapshot returns the page's accessibility tree as compact YAML. It is the cheapest deterministic read we offer, and for most agent tasks it beats burning tokens on raw HTML or pixels. Screenshots exist — for verification and evidence, priced like it.

Errors agents can act on. A failed action returns a structured code — NAV_TIMEOUT, NAV_FAILED, ACTION_TIMEOUT, INVALID_URL — never a stack trace, and failed actions are never charged. The caller is a program; the error surface is part of the API.

Receipts, or it didn't happen

Every settled hosted action is written to a public receipts log (tool, amount, payer, settlement transaction) at /receipts on the endpoint. Subscriptions can't show you that. We run the same proof standard across our fleet — a free x402 Quote Inspector that checks a payment quote before an agent signs it exists precisely because "trust me" is not a payment rail.

Status, stated plainly: the hosted endpoint is live and verified from an independent network path — tool discovery answers, unpaid calls are refused with the exact 402 challenge. The listing is active in the Official MCP Registry (com.scriptmasterlabs/agent-browser v2.0.0) and domain-verified on 402index. The first settled paid call is the next proof milestone; when it happens, it will be on the receipts page, not in a press release.

Honest limits

Datacenter IPs get blocked by some sites regardless of tooling — the tool returns a structured error instead of pretending. There is no CAPTCHA-solving and no proxy rotation in v2; those are separate costs and we will not bundle them silently into a per-action price. It is Chromium via Playwright with basic hygiene, not a stealth fork.

Source (MIT): https://gitlab.com/timothy.walton45/agent-browser
Canonical page: https://scriptmasterlabs.com/agent-browser
Hosted endpoint: https://agent-browser-r7d2.onrender.com/mcp

Built by Script Master Labs LLC, a Service-Disabled Veteran-Owned Small Business in Kinston, North Carolina. Truth first. Proof always. Pay only for accepted delivery.