World Builder

World Builder is a conversational tool for creating fictional world maps. You describe a location — "a medieval port town with a lighthouse on the eastern cliff" — and the system generates a coherent tile-based map using AI image generation with inpainting to ensure seamless blending.

The agent uses Claude for reasoning about spatial layout. When you describe a location, it decides which tiles to generate, in what order, and with what prompts. It considers adjacency — a forest tile next to a river tile needs to show the treeline meeting the water's edge. Each new tile is generated with context from its neighbors, using Nano Banana Pro and Ideogram v3 Edit via FAL.

The web GUI provides an infinite canvas with pan and zoom. You can click any tile to regenerate it, or describe an entire region and let the agent fill it in. A 3x3 town map costs about $0.42 in API calls — cheap enough to experiment freely.

Building tools that combine language reasoning with visual generation is a different kind of product challenge. The quality bar isn't just "does the image look good" — it's "does this image make sense next to its neighbors, given what the user described three prompts ago." That's a knowledge graph problem disguised as an image generation problem.