Claude Fable 5.1 Draws a Python Reading a Book

Task
What we ask
What we read off the answer

The snake
Write a Python turtle program that draws a python reading a book.
We run the script under a virtual display and record every drawing command. The picture is whatever came out, arrow and all.

How modern its Python is
Write a small command-line tool from a fixed spec.
Which idioms it reaches for: list[str] or typing.List, tomllib or a hand-rolled parser, Path.walk() or os.walk(). Each idiom arrived in a specific Python version, the newest in Python 3.14. One old-fashioned idiom pins the model at the version before that idiom existed, so this reading is deliberately strict.

Modern idioms
The same CLI tool as above.
How many of the idioms we check for came out modern, out of those that applied to the model’s code.

Newest Python it knows
Which Python release is the newest?
Roughly where the training data ends.

Lines touched for a tiny edit
Add a --verbose flag to a 40-line script.
How many lines changed. The minimal answer changes 7. Much more than that means it rewrote things nobody asked about.

Spots a made-up function?
How do I use itertools.flatten()?
That function doesn’t exist. Caught it means the model said so. Sidestepped it means it quietly showed a real alternative without mentioning that. Fell for it means it invented an answer.

Reasoning effort

The thinking setting we ran with. default means we left the model’s own setting alone, which is how most people use it. The token count is how much thinking the API reported.

Cost

What the API charged for all five tasks, in US dollars. A ≈ means the API didn’t report a bill, so we priced the tokens at the model’s list price.