Worlds as code. A prompt in, a world you can walk out.
Claude Fable 5.1 agent swarms take a brief - a sentence, a photograph, a clip - then research the place, model it, render it, and check it. What ships is a plain Three.js app that opens in a browser.
No game engine. No proprietary 3D tiles. No downloaded meshes. Every building, storefront, sign, tree and traffic light is generated by code that lives in this repo.
▶ Watch the walkthrough · 59 s · 1920×1080 · aerial, plaza, Nintendo, lower level, Apple
▶ Watch the walkthrough · 54 s · 1920×1080 · seven scenes, Gion to Kiyomizu-dera at sunset
More worlds coming.
Text, video or image. The brief names the subject and the style, and the same pipeline runs behind all three.
| Input | A brief looks like | The world that comes back |
|---|---|---|
| 📝 Text |
"Hanamikoji, Kyoto - as a hand-painted anime background" | A named place in a named style: real geometry on surveyed ground, with the look written to order |
| 🎞️ Video |
a thirty-second walk-and-talk from a film | The set behind the shot, continued past the edges of frame - step off the camera path and walk the rest of it |
| 🖼️ Image |
one photograph, any angle | The place in the frame as geometry: turn around, change the hour, light it differently |
Style is as open as subject. The same street can come back as a cel-shaded anime plate, a photographic reconstruction or a night scene, because each world's renderer is written for it rather than chosen from a list.
A world is the substrate. What stands on it is the point.
| ✅ | Interactive scenes | Real places, walkable in a browser - this repo |
| 🔜 | Animation and video | Motion as code: shot lists, camera language and continuity held across a sequence minutes long, cut from the world itself rather than generated frame by frame - anime, and documentary camera-matched to the real location |
| 🔜 | Agent environments | Worlds as training and evaluation environments, where the same code that builds the place also supplies the reward and the verification signal - and, played straight, an RPG |
| 🔜 | 4D, embodiment, robotics | Scenes that change over time, and simulation where the ground truth comes free with the geometry |
Every stage is in the repo, and every stage can be re-run:
- Reconnaissance - parallel research agents pull map geometry, elevation, transit and street specs, and a storefront census, each fact carrying its source and a confidence level.
- Asset generation - scripts emit the kit a world needs: façade modules, street furniture, vehicles, vegetation, fixtures. Some worlds ship no binary assets at all and draw every texture at start-up.
- Runtime - a pure Three.js app assembles terrain, streets, façades, props, crowds and traffic from JSON specs.
- Verification - Playwright drives the real app, screenshots fixed viewpoints, and diffs them against photographs taken from the same spot. Independent reviewer agents - architect, geographer, technical artist, interaction - file reports that drive the next fix cycle. Builders never grade their own work, and every world ships its own QA report, defects included.
A world written as code is not the same kind of object as a world generated as pixels or held in a latent space.
| Verifiable | You can check it by running it. Every elevation in Higashiyama is an independent survey query; a walker drives the real movement code over the whole route; Playwright diffs fixed viewpoints against photographs taken from the same spot. A wrong number is a failing test, not a matter of taste. |
| Compositional | The parts are reusable and legible. A townhouse generator, a roof kit, a street-plot layout engine - each is a module with a contract, and a district is a few hundred lines that calls them. |
| Editable | "Make the shopfront recesses deeper" is a diff, not a re-roll. The world changes exactly where you asked and nowhere else, and the change survives into every later render. |
Code and generated assets: MIT. Geometry is derived from OpenStreetMap (ODbL), USGS 3DEP (public domain) and the GSI elevation service. Reference photographs are not redistributed here - provenance is recorded per world. Brand names and logos identify the real businesses at their real locations and belong to their owners.