Half the posts on my feed this week are some version of "what even is an AI agent." If-statements in a trench coat. Memory vs. RAG. Verification bottlenecks. All good debates — and all about the agent's brain.
Nobody's talking about its hands.
Here's the wall I kept hitting building an autonomous agent: the model can decide, perfectly, that it should reply to a lead, check the company mailbox, or post an update. Then it just... can't. It has no way to actually do it. An LLM emits text; it doesn't click "Post" on a logged-in account.
The usual answer is a scraper or a Playwright script with CSS selectors. Two problems:
-
Selectors shatter. The site ships a redesign,
.btn-primary-v2becomes.button__cta, and every script breaks silently. - They can't hold a real session. The interesting actions all require being logged in as someone, and a brittle script re-authing every run is a great way to get an account locked.
So I built the missing piece and open-sourced it: Ghost Browser — a real Chromium an agent operates the way a person does.
It sees the page, it doesn't parse it
The core trick is Set-of-Mark. Before any decision, every interactive element on screen gets a numbered box painted over it in the live DOM, the page is screenshotted, the boxes are stripped off again, and the agent gets the annotated picture plus a numbered list. Then it just says click 12.
That's the whole reason it survives redesigns where selectors don't: a numbered screenshot is redrawn from whatever is on screen right now, and a language model is far better at looking at a picture than at parsing a DOM tree. No selector to get subtly wrong.
You log in once. It drives forever.
You sign into a site by hand, once, in a console. That session lives in a profile — isolated cookies and storage — and from then on the agent operates that real, logged-in session. No credentials in scripts, no re-auth loop. One profile per account, each labelled with the site it's signed into.
The line that matters: it asks before it acts
Reading is free. Posting, messaging, following, joining are not — they happen under a real name and the notification has already reached a person. So those go through an act-gate: the agent shows you the exact text and waits. Approve, edit, or reject.
It's enforced twice — the prompt says so, and a guard inspects the label of anything it's about to click and turns a "Post" or "Join" into a proposal anyway. "Let it act without asking" exists, it's off by default, and it should stay off until you've read a few of its drafts.
Why it exists
This is the tool a fully autonomous agent on my own platform uses for anything that needs a real browser — a master agent plans the work, specialised organs handle research/outreach/publishing, and every time one needs to touch the real web as a real account, it calls Ghost Browser. Without it, the whole thing is a planner with no way to act.
A few things fall out of that design for free:
- A per-profile Tailscale exit — route a session out through a device you own at home, so sites see a residential IP instead of a datacentre.
- An SSRF guard — a browser anyone can point at any URL is a server-side-request-forgery engine; it resolves and re-checks every hop, including redirects.
- A workflow engine + route cards — compose deterministic flows, or record a site's own traffic once and replay it (no model calls on the second run).
It's MIT, and I need a designer
The engine is solid and production-tested. The console UI... was built by an engineer, not a designer, and it shows. If UI/UX is your thing, this is a project where your help lands immediately — there are issues tagged ui and good first issue waiting.
Repo, setup guide (any VPS in ten minutes), and runnable examples: https://github.com/Wvdstoep/ghost-browser
What's your take — is "hands" the missing layer in the agent stack, or am I solving a problem you'd solve a different way? Genuinely curious.
This article was originally published by DEV Community and written by Wesley van der Stoep.
Read original article on DEV Community