Build a 3D Learning Game with Claude Fable 5

Fable 5 is not a business model. It shines on long-running, complex, creative tasks, and 3D simulations are exactly that. In this walkthrough I turn a rough sketch of the solar system into a fully working 3D learning simulator with one single prompt, and show you how to reuse the same approach to build an educational game about any subject you want.

What you need

• Claude Code (you can use Cowork if you really want to, but I recommend Claude Code)
• Access to Claude Fable 5, which is available for a limited window before it comes off the Anthropic plan
• Patience for a long build: this kind of prompt runs unattended for a while

1. Why this is a learning and simulation use case (0:00)

Fable 5 was released between 48 and 24 hours before I filmed this, and I have had plenty of time to test it. As I said in my previous video, it is not meant for business use cases. It is meant for long-running tasks, complex tasks, and simulations. So that is exactly what we build: a simulation of the solar system, from scratch, to learn about one of my favorite subjects.

2. Sketch the app first (0:41)

Before prompting, I drew a quick figure of what I wanted: the sun in the center, planets orbiting all around it, each planet as a 3D model with its own moons, and the ability to inspect every body and read its characteristics. Sketching first makes the prompt almost write itself.

3. Turn the idea into a single prompt (1:27)

Here is the exact prompt, ready to copy and paste:

Create a 3D simulation of the entire solar system.

I want to be able to pan around the view. Everything should be in 3D. The planets should orbit in the correct direction and spin in the correct direction as well. Their moons should orbit around them.

I want to be able to click on a planet and see its characteristics, such as mass, radius, surface temperature, age, and a few cool facts about the planet itself.

You can build this as an HTML file or a Next.js application, whichever you think fits best.

On top of this, add any other useful features that would help me learn as much as possible about the solar system.

Notice I do not force the tech choice. HTML file or Next.js application, whichever fits best. I ask for correct orbit and spin directions, clickable planets, and then leave the door open for extra learning features.

4. Choose Fable 5 and set the effort (2:36)

In Claude Code, make sure you actually select the right model: pick Claude Fable 5 in the model selector. For effort, I ran this at the max setting, but high is completely fine. You do not have to crank effort all the way up to get the best performance.

One warning before you hit send: Fable 5 is quite slow, because it reasons quite a bit more than Opus 4.8. A prompt like this will realistically take 10 to 20 minutes, so send it and go do something else.

5. Back from the build (3:18)

In my case it took 30 minutes. Most of that time went into Fable 5 going through the user interface itself, making sure everything was clickable and actually worked. What came back was a one hundred percent functional solar system simulation built from one single prompt.

6. Explore planets, moons, and facts (3:41)

Inside the app you can:

• Zoom in and pan around the whole system
• Click the star or any planet to learn more about it
• Read each body's type, mass, radius, surface temperature, and age
• Switch from planet to planet and browse most of their moons (some planets have hundreds, so not all made it in)
• Toggle orbits, labels, and asteroid belts on and off
• Switch to True Scale, which shows you that we are nothing but tiny dots flying around in space

This was not something a single prompt could produce even a year or so ago.

7. Turn any subject into an educational game (4:26)

The solar system is just my example. If your kid loves any subject out there, you can now build an educational video game for it with the same recipe: sketch what you want, describe the interactions, name the facts you want surfaced, and let Fable 5 handle the build. The same approach works for any 3D simulation you want to learn from.

8. Final thoughts on Fable 5 (4:58)

Go test Fable 5 during the days it remains available; I will be publishing a new use case for it each day of that window. Keep the split clear in your head: business use cases stay on Opus 4.8, but for everything creative and 3D related, Fable 5 is a no-brainer.

Pitfalls and tips

• Select the model deliberately. It is easy to fire the prompt at the wrong model. Confirm Claude Fable 5 is selected before sending.
• Do not over-crank effort. Max works, but high gives you the best performance without the extra wait.
• Expect a long run. Budget 10 to 30 minutes for a build like this and let it work unattended.
• Time-box your testing. Fable 5 is only on the plan for a limited number of days, so use it while it lasts.

Where to go next

For my full breakdown of where Fable 5 and Mythos 5 actually make sense (and where they do not), watch Mythos 5 and Fable 5: My Honest Take. If you want to see parallel workers doing research while you build, check Use Cowork Subagents to 10x Your Productivity.