Anthropic’s Fable 5 can make weirdly fun video games at the click of a button

Anthropic has released Claude Fable 5, the first publicly available version of the closely watched Mythos model. What can Fable actually do? It turns out to be all kinds of things.

Ethan Mollick, a prominent AI researcher and researcher at the University of Pennsylvania, has been playing around with the model and seems to have a lot of fun with it.

In his testing, Fable “basically outperformed every other generic model I’ve used by a wide margin,” Mollick wrote Tuesday on his Substack. He added that it was “able to overcome many issues and achieved some amazing results – and will run for up to twelve hours of execution on a multi-page specification.”

Perhaps most strikingly, Mollick used Fable to create a variety of video games, all of which were created via “one initial vector” in Claude Code, the researcher says.

Among these, Snake is exactly what it sounds like. You’re a snake that looks like Pac-Man and you walk around eating apples. The snake never stops moving, and if it runs off-screen, it dies. It’s an 80s arcade game, but, like many of those old games, it’s strangely addictive. I played it longer than I’d like to admit before I remembered that I’m a gainfully employed writer and not actually a fruit-loving snake.

Then there was Strata, where you wander through a seemingly endless network of subterranean tunnels and the goal is just to light as many lanterns as possible. The graphics look like a degraded version of Myst – they’re not great – but the fact that the game exists at all, created from a single prompt, is impressive.

Mollick even managed to create Duino, a game based on the Duino Elegies, a famous series of poems by poet Rainer Maria Rilke. I like the animation here the most – the player is a lone figure in a night landscape – although there’s not much gameplay other than walking around while clips of Rilke appear on screen.

Aside from the variety of Instant Games produced by Mollick, he also used Fable to create a synchronized map – a visualization that shows how long it takes to travel between any two locations. The accuracy and detail are striking.

The effects are very clear. Software projects that previously required entire teams — games, mapping tools, highly complex specifications — are now run through a single router. It’s a reason for the world’s programmers to rejoice. For founders and operators monitoring AI capability curves, it’s a useful data point on how quickly the floor is rising.