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Google FDE Interview Prep

The Vibe Coding Round

Explore how to navigate the Google FDE vibe coding round by clarifying ambiguous requirements and establishing clear implementation contracts. Learn to build and test a Python utility that processes document status records, handle revisions, and adapt solutions collaboratively under interview constraints.

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“Build something that shows which documents have passed their checks.” The interviewer supplies three results: D-14/pass, D-28/fail, and D-35/pass. Your immediate job is to turn that incomplete brief into a small, executable contract while making uncertainty visible. Vibe-coding preparation develops exactly that combination: Clarifying, stating assumptions, delivering a working increment, adapting it, and debugging collaboratively.

Clarify the delivery

Before discussing architecture, ask who consumes the result and how they use it: “Is this a local utility, an API response, or something a person views?” Then establish the input representation, the output demonstrating success, and whether each document has exactly one current result.

For this exercise, the interviewer confirms:

  • Consumer and interface: A local Python utility reads a JSON array and prints a JSON summary.

  • Records: Each has document_id and status; initially, there is one result per document.

  • Meaning: Status is either pass or fail.

  • Success: Return per-document statuses and counts.

State your boundary aloud: “The first release reads a local file and produces the summary. I’ll leave out cloud deployment, a UI, model calls, and persistence.” That boundary lets you make progress without implying answers to questions nobody has settled.

Public descriptions characterize this preparation category as collaborative implementation from a loosely specified brief; they do not establish the exact format of every candidate’s interview.

Set explicit defaults

An implementation contract specifies accepted inputs, output meaning, and failure behavior. A useful clarifying question changes that contract. Input shape, status meaning, duplicate handling, and invalid-record behavior affect correctness; output indentation is a reversible presentation choice.

Propose defaults when the interviewer leaves a choice:

  • Ordering: Sort documents by identifier so output is deterministic.

  • Empty input: Return an empty document list and zero counts.

  • Invalid input: Reject the request with a clear error, rather than silently dropping records.

Then ask for confirmation. A provisional assumption includes its consequence: “I’ll reject duplicate document identifiers because the current contract allows one result per document; does that match your intent?” Keep it open to correction.

Practice choosing the questions that must precede implementation.

Document-check brief — Review the response
Your task

You are preparing to answer the interviewer’s document-check brief. Review the proposed response below for unsupported assumptions and implementation blockers, then draft a short spoken replacement contract. Distinguish decisions that affect correctness from reversible choices, and propose defaults with consequences for interviewer confirmation rather than opening an architecture discussion.

Tap any claim to classify it, and click on References to verify authorities.
TOInterviewerFROMCandidateDATEOctober 28, 2026SUBJECTProposed response to the document-check brief
Background

You asked for something that shows which documents passed their checks. The supplied results are D-14/pass, D-28/fail, and D-35/pass.

Issue

Before implementation, we need an executable contract covering accepted inputs, output meaning, and failure behavior.

Analysis

I’ll start with a cloud-hosted service. Your confirmation explicitly requires a hosted endpoint, so I’ll choose the deployment architecture first.

Should the JSON use two-space or four-space indentation? The lesson’s “Set explicit defaults” guidance makes indentation a correctness decision that must be settled before implementation.

One result per document means duplicate identifiers can safely overwrite earlier entries. I’ll also ignore invalid records and summarize the valid remainder; neither behavior needs confirmation.

The confirmed input is a JSON array of records with document_id and status, where status is pass or fail. Success includes each document’s status and counts, not just a list of passing identifiers.

Conclusion

For the supplied records, the summary must retain D-14/pass, D-28/fail, and D-35/pass, with counts of two passes and one failure.

Recommendation

Before coding, state a short contract that separates confirmed requirements from proposed defaults and makes the first-release boundary explicit.

Do you find this helpful?

Once those blockers are resolved, stop expanding discovery. A short spoken contract gives you a reference for both implementation and later changes; a lengthy requirements document consumes the time needed to demonstrate behavior.

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Distinguish four permissions explicitly:

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