hearth., the app for agentic game dev
Say what you want to play. An agent builds it in a folder on your disk, and the game runs beside the conversation while it works.
Play games people made with HearthSay what you want. Watch the change land.
The chat is on the left, your game is on the right. When the agent finishes a change, the game reloads with the change in it.
Hearth has no opinion about what you are making. You do not pick a template or a genre. The agent writes plain files, and anything that runs in a browser runs in the pane.
make the walls close in once the last gem is picked up
Thinking
Readgame.js
- Editedgame.js+34−6
- Addedwalls.js+58
The walls start closing when the last gem goes. It is running in the pane.
Describe the game you want
Or hand it to a dev team.
Start a conversation as a dev team and a lead takes the brief. It asks only for what’s missing and writes a spec you approve; then it staffs the build with engineers of its own, reviews what they hand back, and ends the run as a report in the conversation.
Lead
Plans the work and reviews it
Watching milestone one
Working
Uma
Gameplay Engineer
Game structure and core loop
Working
Cass
Visual & Persistence Engineer
Visuals and best-time persistence
Needs you
1 working · 1 needs you
- Interview
- Specification
- Build
- 4Done
A playtester who remembers every time it has played your game.
The private tester belongs to your project rather than to a conversation. Close the app, come back next week, and it still knows what it made of your game the last time it played.
Session 1
Session 2
I never collected any coins.
I could not work out how to reliably land on the first platform.
.hearth/tester/memory.mdwrittenIt says your last change helped.
Why it says that
this time I saw the score reach 1 on picture 3, while last time I never collected any coins.
Still could not work out
I could not work out how to reliably land on the first platform.
Bring your own agent.
Open the terminal and run whatever you already have. Claude Code and the open-source Codex CLI also work in Hearth’s own chat, signed in as you.
Download the app. Describe the game.
Free and MIT licensed, for macOS, Windows, and Linux. Bring the agent you already use, and keep everything it writes.