The home page of this site is a small 3D world. Seville, San Francisco, Canada and New York in one landscape, lit by your own timezone, with my beautiful face as the sun / moon.
I built almost none of it. I just set up an argument between agents and went to bed 💤.
Inception
In August, Matt Shumer posted a game Claude wrote from a single prompt. 3.8 million views, half the replies calling it fake. Then he explained the trick:
The agent (not you!!) breaks the goal into parts, gives each part a specialist builder and a ruthless blind critic sub-agent, with a mandate to only pass if the generated artifact can't be improved.
He calls it the Gauntlet Loop, as in running the gauntlet: the work walks a line of critics and takes its hits. It kinda reminds me of the GAN (Generative Adversarial Network) idea, but in LLM agent form: a generator making things and a discriminator judging them against the real thing, except, in this case, the two do not trade gradients. They trade insults.
Here, one agent builds my mountains. A second agent, with clean context and no idea what the first one was going for, judges the work and criticizes it:
the near sea is a view of the seabed, not a view of water
the gulls do not look anything like birds
Agents have no feelings. That is the whole trick. A critic with clean context has no friendship to protect, so it costs it nothing to be ruthless.
The night
The loop started at one in the morning on 16 August. By 08:46 it had done seven rounds and fifty-two commits: one continuous landmass with a river running in its own channel, and the Golden Gate standing in open water instead of on it. The sun and moon were already running on real solar math from your timezone.
The world was in place, and it was looking quite promising for a completely unsupervised effort.
Making it mine
The loop gets you to good. Then you have to make it yours.
A fresh critic asks "is this beautiful". It will never think to ask "would Miguel like this", so it hands back something competent that could belong to anybody. I wrote down the original vision for the site in a file and made every agent read it before touching anything. Even then, the world still needed a human dropping by:
The birds hang in the wind like laundry. I think they might be pelicans, and I would like them to look more like pelicans, that would be awesome.
The balloon looks more like an egg than a balloon. Nobody has ever pointed at the sky and said "look, an egg".
On that small island to the left there are a couple of tall moving cones that look nothing like a campfire, fix this.
The agents treated all three as serious engineering. The birds are pelicans now and fly like so. The balloon is round. The cones turned out to be my surfboards. The campfire I wanted was added later.
Those refining passes were the part I enjoyed most, and it is where the easter eggs got in: the world now reacts to a few things no page needs to react to. Try clicking the plane. On second thought, don't.
The inner pages went through the same feedback loop, including the one you are reading.
So yes, a loop can already hand you a beautiful world overnight. Whether it feels like yours is still up to you.