I had Claude Fable 5 build Minecraft from scratch

June 14, 2026

1:11

I had Claude Fable 5 build Minecraft from scratch

Here’s something that’ll blow your mind — an AI built a complete Minecraft clone entirely from scratch, without relying on any existing game engine. According to /u/unfortuantelyshelove, Claude Fable 5 was directed to create Pebble, a macOS block game, using only Apple frameworks and handwritten Metal rendering. It’s not just a simple demo; it’s a full game with 879 blocks, 1,188 items, and even real-time synthesized sounds, all built from zero. The game runs smoothly at 200+ fps on a MacBook Air, and the code is open source, so anyone can dig in. What’s wild is that Claude managed to recreate vanilla-like physics and world generation, all test-verified with 456 regression tests — meaning it’s highly deterministic and reproducible, even if it’s not Minecraft’s seed. So, what does this tell us? AI’s not just generating text anymore — it’s building entire software stacks, game worlds, and experiences, all on its own. If this pattern holds, the next frontier isn’t just smarter AI, but AI that’s fully autonomous in creation.

I've been directing Claude Fable 5 (Anthropic's newest model) to build Pebble, a complete, native macOS block-survival game written from scratch in Swift + Metal.

The clip is real a real unedited gameplay of Pebble (that's not Minecraft, that's Pebble). Unfortunately died to a pack of llamas 😭

What it actually is:

About 45,000 lines of Swift, 82 files, zero external dependencies, Apple frameworks only, no game engine, no .xcodeproj
A hand-written Metal renderer (15+ passes, runtime-compiled shaders, SSAO + volumetric god rays + soft shadows + ACES)
Every sound and all music synthesized in real time from oscillators, there are zero audio files in the project
The full game: 879 blocks, 1,188 items, 63 biomes, 100 entity types (55+ mobs with A* pathfinding), three dimensions, redstone, enchanting, villages, raids, and all three bosses
Vanilla-exact player physics and fully deterministic worldgen, pinned by 456 golden regression tests that re-derive the constants, same seed gives a bit-identical world on any machine (tho it doesn't match Minecraft's seeds)
200+ fps at full settings on an M-series MacBook Air (i got up to 500 on my M5 Air)

It's MIT-licensed and open source, so you don't have to take my word for any of it, the code's right there: github.com/thebriangao/pebble

The project is strictly macOS 14+ only (Metal renderer), singleplayer only for now, and you build from source (./pebble install), no notarized download yet. First public beta, so there are definitely bugs I haven't found.

It's an original re-creation built from Minecraft 1.20, no Mojang code or assets, reimplemented from observable behavior, not affiliated with Mojang/Microsoft.

submitted by /u/unfortuantelyshelove
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