L02.md

id	course-da-eda-l02
type	course
title	Challenge 02: Define the answer first
summary	Sketch results.json — keys, types, rounding — before letting the agent write eda.py.
lang	en-US
content_version	1
status	reviewed
reviewed_on	2026-09-12
hints	title body What this checkpoint tests Defining the answer before generating it: sketch `results.json` — keys, types, rounding — before letting the agent write `eda.py`. title body Contract first Decide what `total_revenue` rounding means, what `revenue_by_region` keys look like, and that `rows_total` equals input rows — the suite compares exact numbers. title body When you are done Your sketch names every key in `results.json` and its source column.

Challenge 02: Define the answer first

Gate: self-attested · Points: 10

Write down the shape of results.json before implementing anything: which keys, which types, which rounding rules. The contract in TASK.md defines the form — you decide what "correct" means for each value before you let the agent generate code.

This is the anti-pattern this course exists to kill: "the agent wrote code, it printed something, ship it." EDA only counts if the numbers are checkable.

Checkpoint: you have a written list of the expected keys and you can explain what each one means. Self-attested; record via python verify.py.