Vibe codingEasyvc-g265

Subject Ai code reviewLevel Mid–Senior~12 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

An AI wrote this quick model evaluation. It reports 99.2% accuracy and recommends shipping. As reviewer, why is this number meaningless?

python

1X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2)2 3model = RandomForestClassifier(n_estimators=300)4model.fit(X_train, y_train)5 6preds = model.predict(X_train)            # <-- evaluating here7print('Accuracy:', accuracy_score(y_train, preds))   # 99.2%

What a strong answer looks like

Treat the AI’s output as a draft to verify, not an answer to trust. Name the specific flaw and the input that triggers it, say how you’d catch it — tests, edge cases, reading critically — and how you’d re-prompt or decompose to get it right.

Learn the concepts

Describe your solution

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.