hearth

The 2D game engine built for coding agents.

Your agent builds the levels, writes the behavior, and playtests the game: every engine operation is a typed command it can call. Humans still get a real editor, and the games actually ship.

Download HearthRead the quickstart

Coding agents can’t touch the engines we already have.

Not for lack of capability. Every existing engine was built for a person with a mouse, and quietly assumes one at every step.

  • Every edit means dragging something with a cursor.
  • The scene saves as an unreadable binary blob.
  • You run the game and get a screenshot, not a result.

No cursor, no readable state, nothing to check its own work against. The agent is locked out before it writes a line.

Plain English in. A real change to a real scene out.

Every operation Hearth exposes is a typed command with a structured result, so an agent can build, verify, and cleanly undo. Watch one request land, then reverse.

claude — ~/my-platformer
Claude Code v2.1

Welcome back!

~/my-platformer

> add a patrolling enemy that chases the player
I'll create the enemy, write a patrol-and-chase script, attach it.
⏺ Bash(hearth create entity Level Skitter --position 480,180 …)
⎿ created Skitter · ent_m3kq81rv · Transform, SpriteRenderer
⏺ Bash(hearth create script patrol-chase)
⎿ scripts/patrol-chase.lua · lua · 38 lines
⏺ hearth - attach_script (MCP)(scene: "Level", entity: "Skitter" …)
⎿ Script attached · params: {"chaseRange": 120}
⏺ Bash(hearth playtest smoke)
⎿ smoke passed · 3 assertions · 0 errors
Done — Skitter patrols the platforms and chases on sight.
Describe what to build, run, or undo…
Claude Codehearth (MCP) connected72 tools71 commands
hearth editor — Level
Levelplayer-controller.lua

Not a demo generator. An engine.

Export once. Ship real builds.

One command packages your game as a native app for macOS, Windows, and Linux, signed where each platform allows it. A second command writes a small browser build that itch.io takes as-is. You never touch a build config.

hearth export desktop--allow build
macOSemberfall-darwin-arm64.zip~85 MBad-hoc signed
macOSemberfall-darwin-x64.zip~85 MBad-hoc signed
Windowsemberfall-win32-x64.zip~80 MBunsigned
Linuxemberfall-linux-x64.zip~85 MBunsigned
hearth export web --zip
Webemberfall-web.zip~5 MBplays in the browser

Download the engine. Describe the game.

Free and MIT licensed, forever. The editor, CLI, MCP server, and web and desktop export come in one download. Point your agent at it and start shipping.

hearth init "My Game"
Download Hearth Read the quickstart