Build and grow an open-source browser MMO with community coding agents

In June the poster, u/singing_coach_ai, built World of ClaudeCraft, a free MMO that runs in the browser, over a couple of days with Claude (Fable 5 at the time). The code went on GitHub under the MIT licence and other people started sending changes. Since then the game has been extended by a community of contributors who mostly work through Claude Code, now on Opus 5.5. Release v0.45 replaced the original chibi look with realistic character bodies and hand-keyed animation, painted towns, image-based skies with a day and night cycle, reworked dungeon bosses and new mounts.

The poster counts 22,549 commits and 92 contributors since June, with 153 merged contributions in the v0.45 release alone. Players have made over 90,000 characters and just under 100,000 accounts, and about 500 people play each day. The game is still free. Commenters mostly preferred the old art style, called the new one generic, and some said the game ran at about 12 frames per second in the browser and the standalone app.

Some commenters doubted how much of the work was the agent's, given 92 human contributors; the poster says most contributions were small. The poster says the art change was what the regular players asked for. Others warned that the name could draw complaints from Anthropic and Blizzard.