By FDE Interview Prep, a SourceStrongAI company

In this post12 sections
  1. Why the first questions shape the whole round
  2. Questions about the goal
  3. Questions about the users and who decides
  4. Questions about the data
  5. Questions about constraints: time, money and rules
  6. Questions that waste the clock
  7. The sentence that ends clarifying and starts building
  8. When the interviewer says ‘you decide’
  9. Practice it where the clock is real
  10. Questions people ask
  11. Keep reading
  12. More from the blog

The interviewer reads you a one-line problem and waits. Ask too few questions and you spend the round solving the wrong problem; ask too many and the clock is gone before you have built anything. This post is the question bank for that moment, and it sits inside the decomposition interview guide, which covers the whole round.

The short answer: ask only the questions whose answers would change your first version. Take them from four areas, in the order our method uses: the goal, the users and who decides, the data, and the constraints. Say an assumption out loud for everything else. Then say one sentence that ends clarifying and starts the build.

Why the first questions shape the whole round

A decomposition prompt is a request, not a requirement. “A regional food bank says donated food spoils before it reaches families” could be a warehouse problem, a routing problem, a forecasting problem or a pantry problem. Each one leads to a different build. Your first questions decide which of those you spend the round on.

Palantir says both halves of this out loud. Its careers site tells onsite candidates to talk through how they plan to approach analytical and technical problems and to ask questions if necessary. Source 1Palantir Careers | Getting HiredPublisherPalantirSource typecompany hiring page Its page on open-ended questions tells them to be pragmatic enough to arrive at a concrete approach, and to deliver a functioning idea before expanding it. Source 2Palantir Careers | Navigating Open-Ended QuestionsPublisherPalantirSource typecompany hiring page Ask, yes. But the asking serves the build.

A former Palantir employee says the same. A Palantir-tagged user on Blind who says they worked there wrote, in March 2025, that a bad decomposition looks like not asking questions, making large assumptions without clarifying with the interviewer, and misunderstanding the problem before jumping in. Source 3Palantir FDSE Interview (Blind)PublisherBlind (Teamblind)Source typecandidate report on BlindSource 4Update: interview experience - Palantir new grad FDSE interview (Blind)PublisherBlind (Teamblind)Source typecandidate report on Blind In the same Blind thread, also in March 2025, a Palantir-tagged user who said they had worked there cautioned that there is no one-size-fits-all answer, then suggested understanding the problem thoroughly by asking questions, breaking it into parts and developing a practical solution within the constraints. Source 3Palantir FDSE Interview (Blind)PublisherBlind (Teamblind)Source typecandidate report on BlindSource 5Palantir Interview London HELP !!! (Blind)PublisherBlind (Teamblind)Source typecandidate report on Blind

And the job itself starts here. The Pragmatic Engineer reported, in August 2025, that Colin Jarvis, then OpenAI’s head of forward deployed engineering, said what customers describe in scoping often does not match the data and system reality. Source 6What are Forward Deployed Engineers, and why are they so in demand? (Gergely Orosz)PublisherThe Pragmatic EngineerSource typenews report Treat the interviewer’s prompt the same way: assume the words describe one problem and the facts behind it describe another, and let your first questions find the gap.

Our rule for every question

Before you ask, name the choice the answer would flip. If you cannot name one, don’t ask it: state an assumption instead. This test is ours, not an interviewer’s rubric, and it is the first step of our decomposition method. It cuts wasted questions before you say them.

Questions about the goal

Start here. The goal decides what “done” means.

  • “If this works, I’d expect fewer pounds binned. Is that the win, or is it more families fed?” Flips the whole target. The two lead to different builds.
  • “When you say spoils, what counts?” Flips the metric. Food binned in the warehouse and food that arrives too short-dated to hand out are two different losses.
  • “How do you measure it today, if at all?” Flips your first week. A number that already exists is your baseline; no number means your first version starts by collecting one.
  • “Why now?” Flips the scope. A new grocery partnership, a grant report or a bad month each point at a different slice.

Notice the first one offers a guess. An open “what does success look like?” hands the work back to the interviewer.

“Why now?” comes straight from how FDEs work. Ramp’s Director of Engineering, Leo Mehr, said in an AI Engineer talk published in July 2026 that when a sales rep urgently demands an integration, a well-trained pauses to ask what is driving the urgency. Source 7How Forward Deployed Engineering is done at Ramp — Leo Mehr (YouTube auto-generated English captions)PublisherAI Engineer, YouTubeSource typerecorded talk or interview He described the job, not an interview, but the move carries over.

Questions about the users and who decides

The goal says what must change. The users say who has to change their day for it to happen, and the decider says whose “yes” you need.

  • “Who would use the first version, and what do they do today?” Flips the interface. A warehouse manager on a tablet and an operations director reading a weekly report need different things.
  • “Who owns this problem and the budget?” Flips who you design for when two groups want different things.
  • “Who else loses if we change this?” Flips your guardrail. If donors see their gifts binned, they may stop giving, so pounds received becomes a number you must not hurt.
  • “Is there anyone whose sign-off could stop it?” Flips the order of work. A compliance team, a union rule or a clinical lead can make part of the problem off limits.

For an AI product prompt, also ask: “Is a wrong answer worse than no answer?” It flips everything about review, fallback and how much the model decides alone.

Say the prompt is “support wants an AI to answer refund emails.” If a wrong refund costs money and a slow one costs only patience, your first version drafts replies for a person to approve rather than sending them.

One Palantir-tagged Blind user, replying in November 2022 in a thread about a Palantir London software engineer interview, wrote that you work through a high-level design with the interviewer and that it is important to care about the user. Source 3Palantir FDSE Interview (Blind)PublisherBlind (Teamblind)Source typecandidate report on BlindSource 5Palantir Interview London HELP !!! (Blind)PublisherBlind (Teamblind)Source typecandidate report on Blind Naming a real user early is the fastest way to show that. On a real first call, the same questions become a discovery list.

Questions about the data

In our practice cases, the twist often hides in the data: the request assumes data that is missing, late or owned by someone who has not agreed to share it.

First Round Review quoted Palantir’s former FDE recruiting lead giving this as an example scenario: explain insider trading to the candidate, then ask them to design a solution, including what data they would need and what they would ask the customer. Source 8So You Want to Hire a Forward Deployed EngineerPublisherFirst Round ReviewSource typenews report On Blind in July 2022, a poster who had sat a Palantir interview wrote that “clarifying the question and data schema/source is super important.” Source 3Palantir FDSE Interview (Blind)PublisherBlind (Teamblind)Source typecandidate report on BlindSource 4Update: interview experience - Palantir new grad FDSE interview (Blind)PublisherBlind (Teamblind)Source typecandidate report on Blind

  • “What records already exist about this?” Flips build versus collect. An inventory system that logs arrivals and shipments already tells you how long food sits.
  • “Who owns that data, and can we get it this week?” Flips your first version. Data behind a slow approval means your first version runs on something else.
  • “How fresh is it?” Flips batch versus live. A nightly export is fine for a daily pick list and useless for a same-hour alert.
  • “Can I see one real record?” Flips your assumptions. One example row tells you more about fields, gaps and free text than any description.

For enterprise prompts, add “Which system is the source of truth when two disagree?” On the hospital readmissions question, that could be the admissions record and the discharge notes telling different stories about the same stay. For AI prompts, add “Do we have examples with the right answer attached?” The first flips your joins; the second flips whether you can measure the model at all.

Questions about constraints: time, money and rules

Constraints matter only when they rule something out.

  • “Is anything off limits to automate?” Flips the design. A rule that a person must approve each decision turns an automated system into a review queue.
  • “Can we spend on new tools, or only use what you already pay for?” Flips build versus reuse. If the food bank already pays for a warehouse app with a disposal log nobody uses, turning it on is the first version.
  • “What has already been tried?” Flips your pitch. Proposing the thing that failed last year costs you the room.
  • “Is there a deadline that isn’t moving?” Flips the size of the first version, not its shape.

Ask a constraint question as a choice, not an open door. “Is there a budget?” flips nothing yet. “Can we buy scales, or only use the tablets you have?” flips the plan.

Questions that waste the clock

These sound diligent and change nothing. Each one has a fix.

Instead ofDo this
“What’s the budget?”Ask the spend choice it would decide
“What tech stack do you use?”Assume a common one, unless integration is the problem
“Any other constraints?”Ask about the one rule that could rule out your idea
“How many requests per second?”Ask only once you know it’s a live system
“What should success look like?”Propose a metric, then ask if it’s right
“So you want less spoilage, right?”Restate with a choice: “less binned here, or less that arrives too short-dated?”

Three habits waste time too:

  1. Stacking questions. Five questions in one breath get one vague answer. Ask one, listen, then use the answer in your next question.
  2. Edge cases before the core flow. “What about donations that arrive on a holiday?” can wait until the main path exists.
  3. Asking what you could assume. If any reasonable answer leads to the same first version, say “I’ll assume X” and keep moving.

The mirror mistake is not asking at all. The decomposition interview mistakes post covers that one and how to recover mid-round.

The sentence that ends clarifying and starts building

Stop asking when the next unknowns are cheap to check in the first week of real work, or when two answers in a row have not changed your plan. Our rule of thumb, from our lesson on clarifying before you solve: in a 45-minute case, ask your last question by minute eight and commit to a first version by minute ten. Then close the phase in one sentence, so the interviewer knows you have moved on and what you are building on.

The template:

“I have enough to start. I’ll build for [user] to move [metric]. I’m assuming [A] and [B]; if either is wrong, I’ll say what changes. Here’s the first version.”

Here is what that looks like on the food bank prompt:

You: When you say spoils, what counts: food binned in the warehouse, or food that reaches a pantry too close to its date to hand out?

Interviewer: Mostly what we throw out here.

Changed: the target is warehouse loss, measured in pounds discarded.

You: Who would use the first version day to day?

Interviewer: The warehouse manager. The operations director owns the budget.

Changed: build for someone on the floor, and report to the director.

You: If this works, I’d expect less in the dumpster. Is there anything it must not hurt?

Interviewer: Less in the dumpster, without turning donors away.

Changed: pounds received and distributed become the guardrail.

Three questions, three changes. The data questions I turn into assumptions:

“I have enough to start. I’ll build for the warehouse manager, to cut pounds discarded at each stage, with pounds received and distributed as the guardrails. I’m assuming the inventory system records when each lot arrives and ships, and that discards aren’t recorded by reason today. If discards are already recorded, I skip the new form. Here’s the first version: a weigh-in at the disposal point that writes the stage and the reason.”

That lands the point Palantir makes: arrive at a concrete approach and deliver a functioning idea first. Source 2Palantir Careers | Navigating Open-Ended QuestionsPublisherPalantirSource typecompany hiring page It also shows the three things one candidate put first. In a report on Aced posted in August 2026, about an entry-level Databricks FDE loop that ended in an offer, the candidate called decomposition the most important round and said they had to “clarify stakeholder, scope, and KPI before touching architecture.” Source 9Databricks Forward Deployed Engineer Interview ExperiencePublisherAced (formerly Exponent)Source typecandidate’s personal write-up Your closing sentence names all three. What you say next is covered in answering open-ended questions without rambling.

Saying it out loud matters. Palantir’s recruiting blog, in an August 2022 post for intern and new-grad candidates, advises sharing questions, comments and observations so interviewers can see how you approach the problem. Source 10From Pipeline to Prospect: Insights and Advice from Palantir Recruitment (Palantir Blog; archived copy)PublisherPalantir Technologies (Palantir Blog on Medium)Source typearchived company page Scoping you do in your head earns nothing.

When the interviewer says ‘you decide’

Sometimes the answer is “you tell me” or “whatever you think.” Treat it as a prompt to decide, not a trap: the answer probably isn’t in the case, so choosing is the useful move.

Use the same shape every time: choose, give one reason, label it, and say what flips.

“Then I’ll assume the food bank can’t buy new software this year, because that’s the cheaper guess to get wrong. If that’s wrong, a vendor tool goes on the list before a custom form.”

Offer two options only when the choice is expensive to reverse, and even then say which one you’d take. Don’t ask the same question again in different words. And write the assumption where you can both see it, so you can come back to it when a later answer changes it.

A quick check before your next round

Clarifying, in order

  • For each question, the choice its answer flips
  • A goal question that gives you a metric
  • A user question that names who decides
  • A data question: what exists, who owns it, how fresh
  • A constraint question, only if it could rule something out
  • Your last question by minute eight
  • Every other unknown said as “I’m assuming X; if not, Y changes”
  • The closing sentence, out loud, then the first version

Practice it where the clock is real

Run three free prompts: the food bank spoilage question, the one this post used, plus the city bus reliability question and the hospital readmissions question. Write your first three questions and the choice each flips, then compare them with the clarify step in each framework.

In Pro, the full lesson on clarifying before you solve works through a whole opening turn by turn, with the answer each question got and what it changed. Pro starts with a free trial. The plans are on the pricing page.

Then test it against a clock. The free practice case puts you in front of an AI customer who holds back facts until you ask the question that finds them. It runs on a 10-minute clock and it is free. Sign in with a Google account or an email link to start. Open with three questions built the way this post builds them, each with the choice it flips, and see how many facts they surface before minute ten.

GlossaryForward deployed engineerA software engineer who builds and ships production systems inside a customer’s problem and environment, accountable to that customer’s outcome.More on Forward deployed engineerGlossaryAgentA system in which a model chooses steps and tool calls to complete a task, within limits the design sets.More on Agent

Questions people ask

How many clarifying questions should I ask in a decomposition interview?

Ask only the ones whose answers would change your first version, and state an assumption out loud for the rest. Palantir’s advice is to ask questions if necessary and still arrive at a concrete approach.Source 1Palantir Careers | Getting HiredPublisherPalantirSource typecompany hiring pageSource 2Palantir Careers | Navigating Open-Ended QuestionsPublisherPalantirSource typecompany hiring page

What if the interviewer won’t answer my clarifying questions?

Treat that as an invitation to decide. State the assumption you are making, say why it is reasonable, note what would change if it were wrong, and move on to a first version.

Why do clarifying questions matter so much for FDE roles?

Because the job starts from vague requests. Ramp’s Director of Engineering Leo Mehr said in an AI Engineer talk published in July 2026 that when a sales rep urgently demands an integration, a well-trained FDE pauses to ask what is driving the urgency, who will use it and whether the workarounds have been exhausted.Source 7How Forward Deployed Engineering is done at Ramp — Leo Mehr (YouTube auto-generated English captions)PublisherAI Engineer, YouTubeSource typerecorded talk or interview

How long should I spend on clarifying questions?

Our rule of thumb, from our own method rather than any interviewer’s rubric, is that in a 45-minute case you ask your last question by minute eight and commit to a first version by minute ten. State an assumption for anything you haven’t asked by then.

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