Hearth.

Decision-model browser agent for rental search.

GitHub

Overview

Hearth is an AI agent that searches four rental marketplaces (Craigslist, Facebook Marketplace, Redfin and Zillow) from one plain-language request. It drives a real Chrome browser so you can watch every click, and it merges everything into a single shortlist.

Architecture

Hearth architecture: the Hearth UI talks to a local Python server whose agent loop observes the page, asks the TypeSafe decision model for an operation and target, guards, and acts over CDP through browser-harness on a dedicated Chrome that opens Craigslist, Facebook Marketplace, Redfin and Zillow

Swipe to see the whole diagram, or tap to open it full size.

Decisions, not guesses

Hearth separates deciding from talking. A dedicated TypeSafe decision model picks each browser action and returns a probability for every option, so each choice is scored, traceable and cheap (a whole search costs a fraction of a cent). It’s the same pattern behind Agent Tool Selection: The Tool Your Agent Almost Called, where confidence-gated decisions cut empty or unfinished agent replies from 21 to 3.

Read-only by design

  • Never messages a seller, saves a listing or starts a transaction
  • Only clicks controls it can see; never enters credentials or creates accounts
  • Says when a source stopped early instead of pretending the search finished
  • Runs entirely on your machine, with the API key kept in .env

Built on

Hearth is built on Jev Ultrafast by Browser Use, with decisions from TypeSafe.

How It Works

1

Ask

Type or speak a search like 'studio in Oakland under $2,500, near BART'. Hearth turns it into filters for location, budget, home type, recency and marketplaces.

2

Decide

At every step, a TypeSafe decision model scores the possible next actions and picks one with a confidence score. Searches fan out across marketplaces, and every decision shows up in a live activity rail with its cost and duration.

3

Drive

Hearth opens one tab per marketplace in a dedicated Chrome and carries out each decision with real clicks you can watch.

4

Handle walls honestly

On a bot check, sign-in wall or rate limit, Hearth reports it, keeps what it already collected and moves on. It never solves CAPTCHAs or enters credentials.

5

Shortlist

Returns a first match, a shortlist and a report of up to 18 listings with photo, rent, facts and a direct link. A tick means the listing proved a detail; a question mark means it didn't say.

Tech Stack

PythonJavaScriptBrowser Use / Jev UltrafastTypeSafe decision modelChrome DevTools Protocol