World of ClaudeCraft Is a Free, Open-Source MMO Built With AI Tools

A developer going by levy-street has released World of ClaudeCraft, a small browser-based MMORPG inspired by World of Warcraft Classic. The developer says it was “vibe coded” over a weekend using Anthropic’s Fable 5 model, and it’s available to play without a download.

The project was shared in a Reddit post, where levy-street describes it as a working micro-MMO rather than a simple tech demo. The full codebase is also available through the game’s GitHub repository, so anyone can inspect it, fork it, or tinker with it.

For something built as a hobby project, World of ClaudeCraft has a surprising amount in place. It includes nine vanilla-style classes, three zones covering levels 1 through 20, about 60 quests, a Gravecaller storyline, and five-player elite dungeons with boss mechanics. Combat is said to use vanilla-style formulas, including armor reduction and rage conversion.

It also supports real-time multiplayer. Players can group up, trade gear, duel, and play on shared servers, while an offline browser mode runs on the same deterministic core. The source notes that spell icons and sound effects are procedurally generated as well.

There are still obvious limits here. This isn’t a commercial-scale MMO, and “built over a weekend” doesn’t mean it’s ready to compete with long-running live games. But as a playable, open-source experiment, it’s an interesting snapshot of where AI-assisted game development is right now. Small, rough around the edges, but functional.