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Interview guides

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AI engineers

How to interview AI engineers

Interview AI engineers on production LLM work: fix a broken retrieval pipeline, design a service with evals and fallbacks, then defend the trade-offs.

AI engineer loop4 rounds · 3 AI interviewers
KWKenji Watanabe · AI engineerIn progressShortlisted
  1. 1✓AI screening interviewLLM features taken to productionARIARunningStrong · 88
  2. 2✓Live codingA retrieval bug in a RAG service we builtMAXRunningBug fixed
  3. 3✓System designA support assistant with evals and fallbacksMAXRunning1 gap: fallback
  4. 4✓Follow-upCost, latency and failures in the designNIXRunningHire · 85
Your team decidesDebugs from evidence, gates changes on evals86/100

The AI engineer interview loop

Four rounds, each run by an AI interviewer with its own report. Candidates take every round on their own schedule.

ARARIA · Live interviewQuestion 2 of 6
AR

Tell me about an LLM feature you took to production. What broke after launch?

KW“Contract search. A week in, answers quoted expired versions, so we stored the effective date on every chunk and filtered on it before ranking.”
Follow-up preparedHow did you catch it, and how fast?
Signals capturedFound the root causeOwned production

Round 1 · AI screening interview

LLM features they have taken to production

A real two-way conversation that follows up on the answers the candidate actually gives.

MAMAX · System designSupport assistant
  1. 1✓RetrieveHybrid search over the docs, filtered by productSearchRunningSolid
  2. 2✓AnswerThe model writes only from cited chunksLLMRunningCites sources
  3. 3✓Evaluate300 graded questions run on every changeEvalsRunningGates deploys
  4. 4✓FallbackModel down: retry the same providerFailoverRunningNo second provider
MA

What if retrieval finds nothing relevant?

KW“Say we don't know and offer a person. A confident wrong answer costs more than no answer.”

Round 3 · System design

An LLM service with evals and fallbacks

The candidate designs on a shared whiteboard while the AI probes trade-offs and failure modes.

MAMAX · Live codingRAG service we built

Answers cite the wrong documents. Find the bug and fix it.

1def search(query, k=5):2    model = index.meta["embed_model"]3    q = embed(query, model=model)4    return index.search(q, k)
StepWhat the candidate didCheck
Root causeQueries embedded with a newer model than the indexCheckingFound
FixRead the model from the index metadataCheckingTests pass
GuardFail at startup on a model mismatchCheckingAdded

Round 2 · Live coding

A retrieval bug in a RAG service we built

The candidate solves a live problem while the AI scores the result and the reasoning behind it.

NINIX · Follow-upLive
NI

Your design costs $0.12 per answer. How would you cut it in half without losing quality?

KW“Cache repeated questions, send simple ones to a small model, keep the large model for the rest. The eval set tells us if quality drops.”
Projected cost per answer$0.05
Report notesEvals as the guardrailConcrete numbers

Round 4 · Follow-up interview

Cost, latency and failures in their design

The AI questions the candidate on their own earlier work, so you see whether they understand it.

What to assess in a AI engineer interview

Score every candidate on the same 6 skills, rated against evidence from the rounds, so two reviewers reach the same call.

  • LLM application engineering
  • Retrieval and RAG
  • Evaluation and testing
  • System design for AI services
  • Cost and latency trade-offs
  • Production reliability
HRScorecard · AI engineerRisk: Low
LLM application engineeringVery strong
Retrieval and RAGVery strong
Evaluation and testingStrong
System design for AI servicesStrong
Cost and latency trade-offsStrong
Production reliabilityWeak
Criteria met · 5 of 686/100

AI engineer interview questions

Use them in your own loop, or let ARIA, MAX and NIX ask them, follow up on the answers and score them.

1

Tell me about an LLM feature you took to production. What broke after launch?

2

This RAG service returns answers from the wrong documents. Find the bug and fix it.

3

Design a support assistant that answers from our docs. How do you test it, and what happens when the model is down?

4

Your design costs $0.12 per answer. How would you cut it in half without losing quality?

5

How would you know a model upgrade made answers worse before customers did?

Integrity in every round

A second voice or screen, pasted work and claims that contradict earlier rounds are flagged with timestamps.

No scheduling between rounds

AI engineers take each round when they are ready, in any time zone.

Your team makes the call

Hello Recruiter evaluates and organises the evidence. People decide who moves forward.

Frequently asked questions

Still have a question?

See the loop on one of your open roles.

How do you interview AI engineers?

Interview AI engineers on production LLM work: fix a broken retrieval pipeline, design a service with evals and fallbacks, then defend the trade-offs. A strong loop has four rounds: AI screening interview (LLM features they have taken to production), live coding (a retrieval bug in a RAG service we built), system design (an LLM service with evals and fallbacks) and follow-up interview (cost, latency and failures in their design).

What skills should you assess in a AI engineer interview?

LLM application engineering, Retrieval and RAG, Evaluation and testing, System design for AI services, Cost and latency trade-offs and Production reliability. Rate each one Very strong, Strong, Weak or Very weak against evidence from the rounds, not impressions.

How does Hello Recruiter detect cheating in AI engineer interviews?

Every round is monitored for integrity signals such as a second voice or screen, work pasted in from outside the workspace, and claims that contradict earlier rounds. Each signal is timestamped in the candidate's report.

What does the hiring team get after each round?

A report with an AI score out of 100, criteria marked Met, Not met or Not yet evaluated, skills rated Very strong to Very weak, a risk level and timestamped integrity signals. Hello Recruiter evaluates; your team decides.

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Run this loop on your next AI engineer hire

Start from this loop or generate one from your job description. Your team makes the call.