Veld — an AI-built voxel sandbox (GPT-6.1 Sol)

GPT-6.1 Sol built this voxel sandbox from a single prompt. This is the real, unedited first result: no human fixes.

Explore a seeded world of bays, hills, trees and beaches. Mine and place seven block types, manage your inventory and watch a four-minute day turn to night.

How to play

1. Press Run game below, then click Enter the world. Your browser captures the mouse so you can look around.
2. Walk with W A S D, hold Shift to sprint and press Space to jump.
3. Point at a block and left-click to mine it; right-click to place the selected block.
4. Press 1 to 7 (or use the mouse wheel) to pick a block type, and E to open the inventory.
5. Press F to save your world, H for in-game help and Esc to release the mouse.

Controls

Mouse to look · WASD to walk · Space to jump · Shift to sprint · left-click to mine · right-click to place · 1–7 or wheel to pick a block · E inventory · F save · H help · Esc to release the mouse.

Browser and device

• Best on: a desktop or laptop in a current Chrome, Edge, Firefox or Safari, with keyboard and mouse.
• Needs: WebGL, and pointer lock (the game asks for it when you click in).
• Phones and tablets: not supported; the voxel games need a keyboard and mouse.
• Audio starts after your first click or key press.
• Use the fullscreen button for the largest view.

How it was made

• Model: GPT-6.1 Sol (Codex CLI), extra-high effort
• Build time: 21m 41s, one run, first result only
• Cost: about $0.60–$0.64 at API prices (estimate)
• Fresh folder, no internet, three.js provided

Its rival, Tessera Wilds, was built by Claude Opus 5.5 from the same prompt. Play both and decide which you prefer.

Watch the head-to-head

Watch the full build comparison on YouTube (AI model vs AI model, same prompt, voxel sandbox builds).

Get the source code and guide

Want to see how it works and remix it? Veld: AI-Built Source + Guide on Gumroad has the untouched game source, the exact prompt, build stats and a 9-page guide with three remix exercises. Or get all four games' source and guides in one bundle. No purchase is needed to play.

Licence and price

Free to play; pay what you want if you enjoy it. Original names and procedural visuals with generated sound. three.js is included under its MIT licence. Your world save is stored in your browser at this page's address, so clearing site data can remove it.

More: YouTube · Gumroad · Notion templates