Python Docstring Conventions — ELI5

Think of a docstring like a sticky note on a recipe card. The recipe itself is the code — the steps the computer follows. The sticky note is for humans: “This makes chocolate cake. Serves 8. Takes 45 minutes. Don’t forget to preheat the oven.”

In Python, a docstring is a short explanation written right inside a function, class, or module. When someone looks at your code, the docstring tells them what the code does, what it needs, and what it gives back — without them having to read every line.

Why does this matter? Because code you wrote last month already feels like someone else wrote it. A good docstring brings you back up to speed in seconds instead of minutes. For teammates, it is even more important — they have never seen your code before.

The trick is being specific. “Processes data” tells nobody anything. “Reads a CSV file and returns a list of customer names” tells you exactly what to expect. The best docstrings answer three questions: What does this do? What goes in? What comes out?

Python even has built-in support: typing help(some_function) in the terminal shows the docstring. IDEs display it when you hover over a function name. The investment of one sentence pays off every time someone uses your code.

The one thing to remember: A docstring is a one-sentence promise about what your code does — write it for the person who will read your code six months from now, including future you.