JSON Extraction Endpoint Passes Question Explained
This worked AI Engineer Interview practice question tests Problem Framing. Try the answer first, then review why D is the best choice.
Short answer
The correct answer is D. Segment the failures by input shape, model, finish reason, and token limit to find what the 3% have in common..
You cannot fix a failure you haven't characterized: segmenting the 3% tells you whether this is truncation, an input class, or a model quirk — each has a different fix. The key is to match the exact action in the prompt to the tool, command, or concept that performs that action directly. Here, D. Segment the failures by input shape, model, finish reason, and token limit to find what the 3% have in common. is the only option that satisfies the scenario without adding unrelated behavior.
The Question
A JSON-extraction endpoint passes all 40 test cases but returns malformed output on 3% of production requests. A teammate wants to retry until the JSON parses. What is the first thing you do?
Why D is correct
You cannot fix a failure you haven't characterized: segmenting the 3% tells you whether this is truncation, an input class, or a model quirk — each has a different fix. The key is to match the exact action in the prompt to the tool, command, or concept that performs that action directly. Here, D. Segment the failures by input shape, model, finish reason, and token limit to find what the 3% have in common. is the only option that satisfies the scenario without adding unrelated behavior.
Why the other options are wrong
Option A does not match the requirement in the prompt. The correct answer is D because You cannot fix a failure you haven't characterized: segmenting the 3% tells you whether this is truncation, an input class, or a model quirk — each has a different fix.
Option B does not match the requirement in the prompt. The correct answer is D because You cannot fix a failure you haven't characterized: segmenting the 3% tells you whether this is truncation, an input class, or a model quirk — each has a different fix.
Option C does not match the requirement in the prompt. The correct answer is D because You cannot fix a failure you haven't characterized: segmenting the 3% tells you whether this is truncation, an input class, or a model quirk — each has a different fix.
Key idea: Problem Framing
Every question is a production situation an AI engineer interviewer can put to you: a failing endpoint, a cost spike, an agent that loops, an eval that disagrees with users. The best answer is almost always the one that measures or contains the problem before it changes the model or the prompt. If you miss a question, note which habit it tests: decompose before you fix, put the security boundary where the side effect happens, and trust an eval only after you check what it covers. The 12 open-ended questions with answer guides are at aijobprep.app/questions/ai-engineer.html.
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