Opus 5.5 rebuilds San Francisco in Unreal, with Jev driving every NPC
A tutorial-style demo in which Claude Code connects to Unreal Engine via MCP, Opus 5.5 generates San Francisco block by block from real city data, and Jev drives pedestrians, pets and vehicles with sub-second decisions.
Matthew Berman had Claude Opus 5.5 recreate San Francisco in Unreal Engine... and every person, pet and car in it is driven by Jev the trick is splitting the work: Opus builds the city, Jev runs the life inside it, but there's a smart way to set it up: - step 1: connect Claude Code to Unreal Engine through MCP, and have Opus read the project first - step 2: feed it real city data: building footprints, heights, the street grid - step 3: Opus generates the city block by block: downtown towers, parks, the bay, the bridge - step 4: add the life: pedestrians, pets, cars, buses on real streets - step 5: every agent asks Jev a quick question: cross now or wait? which lane? where next? - step 6: Jev answers in under a second for fractions of a cent, so thousands of agents can decide on their own - step 7: build and check one district at a time, then fly the camera out over the whole city and that's why it works at this scale... a reasoning model is too slow and too expensive to decide for thousands of cars a decision model was built for exactly that Opus builds, Jev decides
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