By FDE Interview Prep, a SourceStrongAI company

In this post10 sections
  1. When the interviewer becomes the customer
  2. The core moves, with the words to say
  3. When the customer is annoyed, vague or wrong
  4. A short role-play, turn by turn
  5. Mistakes that end the round early
  6. What employers publish and what candidates report
  7. How to rehearse with a partner or on your own
  8. Questions people ask
  9. Keep reading
  10. More from the blog

Partway through your loop, the interviewer becomes the CTO of a company that wants an AI system, or a stakeholder on a kickoff call. That is the customer role-play interview. Candidates for (FDE) roles report it at AI companies and enterprise software firms. Source 1FDE Interview Experience at Google (L4)PublisherBlind (teamblind.com)Source typecandidate report on BlindSource 2FDE Technical Challenge: Inbound Carrier Sales (PDF)PublisherIanDalton (GitHub)Source typecandidate’s take-home repositorySource 3Kong PS / Forward Deployed Engineer — Take-Home ExercisePublisheralexscottan (GitHub)Source typecandidate’s take-home repository For every other round, read the FDE interview guide.

The short answer: treat it as a real customer call. Frame the call, ask before you propose, play back what you heard, acknowledge before you disagree, offer options with a recommendation, commit only to what you control, and close with owners and dates. Those moves are our method, not a rubric any employer publishes. Below are the exact words for each, a worked exchange and a way to rehearse.

When the interviewer becomes the customer

The switch is abrupt: the person across the table now has a business, a boss and a grudge. Three things change:

  • Your audience changes. A CTO does not care that you picked a queue. They care whether their team’s week gets better.
  • Information stops flowing freely. In a design round, the interviewer volunteers constraints. In a role-play, the “customer” often holds facts back until you ask the right question.
  • Your words become commitments. “We can have that by Friday” is a promise, and a good interviewer will hold you to it.

The core moves, with the words to say

Each move is one short thing you say. Practice them out loud until they sound like conversation.

Frame the call once, then stay in character

Step out of character one time, at the start: “Before we begin: am I your vendor’s engineer or an outside consultant? And do you want a proposal by the end, or agreed next steps?” Then stay in the role until the interviewer drops it. This is the opening the free lesson What customer rounds look like, and the core moves teaches.

Set an agenda

“Here’s how I’d like to use our time. I’ll ask what’s going on and what a good outcome looks like, play it back to make sure I have it right, then suggest a first step. Does that work for you?”

Ask before you propose

Five questions that work in almost any role-play:

  • “What happens today, step by step, when this goes wrong?”
  • “Who feels it most: your team, your customers, or your boss?”
  • “What have you already tried, and why didn’t it stick?”
  • “If this works, what’s different a month from now? How would you know?”
  • “What can’t change: systems, data rules, the date?”

Ask one at a time and follow the answer before moving on. Our post on discovery call questions for engineers has a longer list by situation, and the Pro lesson Diagnose before you prescribe teaches how to follow an answer down to the real problem.

Play it back, then stop talking

“So the goal is fewer escalations reaching your senior agents, your team can’t take on a new tool before the holidays, and customer data stays in your cloud. Did I get that right?” Then wait. The correction you get is often the most useful thing said in the whole round.

Acknowledge the specific point before you disagree

Not “I understand your frustration”, which tells the customer you heard a tone. Name their point in their words: “You were promised this would be live this month, and it isn’t. That’s a fair thing to be angry about.” Then stop, and let them respond.

Propose the smallest first version

“I’d start with one queue and one team, with a person approving every action, so you see it working on your own data before we commit to more.”

Offer options with a recommendation

The customer wants the assistant live this month, but their new API gateway isn’t ready until next quarter:

“There are three ways to do this. We wait for your new gateway, which costs nothing but moves your date. We read from a replica through an adapter, which keeps the date and can be switched off in a day. Or we start with a nightly extract, which is fastest but a day stale. I’d pick the adapter. If your security team can’t approve it in time, I’d switch to the extract.” Every option should be one you would carry out without complaint.

Commit only to what you control

“I can’t promise Monday, because your security review decides that, and I don’t run it. I’ll have the design to your reviewer by Wednesday noon, and I’ll tell you on Friday whether Monday holds.” An owner and a date on everything you promise, and nothing you don’t control. The Pro lesson The moves inside a hard conversation drills this, acknowledgment, and options with a recommendation.

Close with owners and dates

“To recap: we agreed to start with one queue. I’ll send the design to your security lead by Wednesday. Your ops lead gets us read access by Friday. Still open is whether the weekend team is in the pilot, and I’ll have an answer by Monday. I’ll put this in an email today.”

When the customer is annoyed, vague or wrong

The interviewer will push. Here is what each kind of push sounds like, and what to say back.

Annoyed. “We’ve been waiting for months. Why should I trust you now?” Don’t defend the timeline. Acknowledge the specific failure, own the next step, and ask one question: “You’re right that it’s late, and that’s on us. What is the delay costing your team each week? I want to fix the part that hurts most first.” The Pro lesson De-escalating an angry customer teaches how to lower the temperature within a couple of exchanges.

Vague. “I just want it to be smarter.” Ask for a story, not a definition: “Walk me through the last time it got something wrong. What happened, and who noticed?” If they still can’t say, offer two concrete readings and let them pick: “Do you mean it answers more questions on its own, or it makes fewer mistakes on the ones it answers?”

Wrong. “Skip the pilot. Turn it on for every region on Monday.” Say yes to the goal and no to the method: “Yes to getting value in front of every region fast. Going everywhere at once is the part that makes one bad week everyone’s bad week. Here’s a way to reach all regions by the end of the month, with a check at each step.” Practice this with the architect who insists on his own framework.

Demanding a promise. “Just tell me it will be done by the end of the month.” Give a decision point instead of a date you don’t control: “I can’t give you that date today. I can tell you by Thursday whether it holds, and what we’d cut to keep it.” Telling the CTO the integration will be three weeks late is the hard version, and our post on telling a customer the project is late walks through the words.

A short role-play, turn by turn

Here is a practice exchange of our own. The company is fictional: a regional freight company whose AI email assistant is routing customer requests to the wrong team.

Customer (VP of customer operations): “Your assistant sent a damaged-goods claim to billing yesterday. The customer called our CEO. I’m about ready to turn the whole thing off.”

You: “A claim that sat in the wrong queue while the customer escalated to your CEO is exactly the failure you hired us to prevent. Before we decide anything, can I ask what happened next?”

Why it works: specific acknowledgment, no defense, and a question that keeps the customer talking.

Customer: “Billing bounced it back after a day. Nobody owned it.”

You: “So the damage is the day it sat unowned, more than the wrong label. Is that fair?”

Why it works: the playback reframes the problem around the outcome. Now you can fix ownership, not only accuracy.

Customer: “Fine. But I need to know it won’t happen again.”

You: “I can’t promise the model never mislabels an email. I can make sure a mislabeled claim never sits unowned. Three options. Turn it off for claims only, which is safe but puts claims back on your team. Keep it on, but send anything it’s unsure about to a person, which keeps most of the time saved. Or keep it as is and add an alert when a claim bounces, which is fastest but reacts after the fact. I’d pick the second, plus one rule: any claim a team bounces goes straight to a named person on your claims desk, with an alert. That’s the part that means it never sits unowned. What matters most to you: speed, or never seeing this again?”

Why it works: an honest limit, a commitment you control, real options, and a recommendation with a question that hands the decision back.

Customer: “Never seeing this again.”

You: “Then claims the assistant is unsure about go to a person, and any bounced claim goes to your claims lead, starting tomorrow. I’ll send you every claim misrouted this week, and the routing change, by five o’clock today, and on Friday I’ll show you how many claims went to a person and whether any bounced. Does that work?”

Why it works: the four-part close in miniature: what we agreed, who does what, by when, and what’s still open (whether any claims bounced, answered on Friday).

Mistakes that end the round early

  • Pitching in the first minute. “We’ll use a fine-tuned classifier” before you know what’s wrong. Fix: ask at least two questions before any solution.
  • Interrogating without playing back. Ten questions in a row feels like an audit. Fix: after every few answers, restate what you heard.
  • Generic empathy. “I understand your frustration” with nothing after it. Fix: name their specific point, in their words.
  • Promising what someone else controls. “We’ll definitely hit the date.” Fix: commit to the next step and the date you’ll know.
  • Staying shallow. Customer rounds can be technical: one candidate reported, in August 2019, a Stripe role-play that expected a strategy down to SOAP versus REST, with timelines and commitments. Source 4Hacker News comment by eldavido on 'Lessons from Stripe'PublisherHacker NewsSource typecandidate comment on Hacker News Fix: when the customer asks how, go technical, then translate back to their outcome.
  • No close. The round ends and nothing was decided. Fix: always finish on who does what, by when.

What employers publish and what candidates report

Palantir’s Getting Hired page organizes its interview-prep guides around engineering competencies, and none of them is a customer role-play round. Source 5Palantir Careers | Getting HiredPublisherPalantirSource typecompany hiring page Its interviews have still put a customer inside the prompt: First Round Review reported, in February 2026, that a former Palantir FDE recruitment lead described a scenario where candidates were asked what data they would need and what they would ask the customer. Source 6So You Want to Hire a Forward Deployed EngineerPublisherFirst Round ReviewSource typenews report

One brief published by the hiring side does describe a live role-play: a public repo from a GitHub organization named Axium Industries describes a 60-minute interview for a Forward Deployed Engineer (AI) role, in which an interviewer plays the customer while you build a small data-science . Source 7Second-stage interview — Forward Deployed Engineer (AI)PublisherAxium Industries (GitHub organization)Source typecompany hiring page As that repo describes it, the session is scored on customer instincts, agent architecture, judgment and verification, and communication. Source 7Second-stage interview — Forward Deployed Engineer (AI)PublisherAxium Industries (GitHub organization)Source typecompany hiring page

The rest is candidate reports, each from one person:

  • Google. One candidate reported, in July 2026, a 60-minute system architecture round run as a role-play, with the interviewer as a company’s CTO. Source 1FDE Interview Experience at Google (L4)PublisherBlind (teamblind.com)Source typecandidate report on Blind The poster was later rejected, so it describes the format, not a winning answer. Our post on the Google FDE loop covers it.
  • Stripe. One candidate wrote, in August 2019, of a one-hour role-play planning a large payment integration, down to SOAP versus REST, with timelines and commitments. Source 4Hacker News comment by eldavido on 'Lessons from Stripe'PublisherHacker NewsSource typecandidate comment on Hacker News
  • Kong. One candidate’s repo from September 2026 describes a take-home that opens with a kickoff call where the interviewer plays a customer stakeholder. Source 3Kong PS / Forward Deployed Engineer — Take-Home ExercisePublisheralexscottan (GitHub)Source typecandidate’s take-home repository
  • HappyRobot. One candidate’s repo from June 2026 describes a proof of concept presented to a customer played by the interviewer. Source 2FDE Technical Challenge: Inbound Carrier Sales (PDF)PublisherIanDalton (GitHub)Source typecandidate’s take-home repository
  • No company named. One Blind commenter described, in July 2026, scoping rounds as role-plays with a fake client where you uncover the real problem and propose a solution. Source 8FDE Interview Prep QuestionPublisherBlindSource typecandidate report on Blind

Prep sites say the interviewer may play a deliberately frustrated customer, and cite no source. Source 9Forward Deployed Engineer Interview: The Definitive 2026 Guide (FDE)PublisherAced (formerly Exponent)Source typeinterview prep siteSource 10Forward Deployed Engineer Interview Questions (and How to Answer Them)PublisherhinehalSource typeinterview prep siteSource 11Forward Deployed Engineer (FDE) Interview Questions GuidePublisherFDE AcademySource typeinterview prep site None of the employer pages in our research says how often a role-play appears or how it counts against the other rounds.

How to rehearse with a partner or on your own

With a partner. Give them a card with a short brief, a few hidden facts and one fact they should reveal only if asked directly. Tell them to push back once, get annoyed once, and ask you for a promise once. Record it, score it on the checklist below, then swap roles.

On your own. Take a free question and answer it out loud, then compare. The security lead who won’t grant production credentials and a customer’s unrealistic demands by email are good starts. Both are free, each with a model answer to compare yours against.

Score your rehearsal

  • I framed the call and set an agenda before asking anything.
  • I asked at least two questions before proposing a solution.
  • I played back what I heard, and waited for a correction.
  • I named the customer’s specific point before disagreeing.
  • I proposed a small first version.
  • I offered real options and said which I’d pick and why.
  • Every promise had an owner and a date, and I controlled it.
  • I closed with what we agreed, who does what, by when, and what’s open.

For live practice with a customer who answers back, use the free case. The free practice case at /try puts you in front of an AI customer: a city whose mayor has already promised an AI review tool, holding facts it reveals only when you ask the right question. Pitch a tool before you’ve asked where the time goes, and it pushes back. It is free, with a sign-in. Run the free practice case once, then score yourself on the checklist above: which move did you skip?

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

What is a customer role-play interview, as candidates report it?

Candidates report an interviewer playing a customer, such as a CTO or a project stakeholder, while you run the conversation. One candidate described it, in July 2026, as uncovering a fake client’s actual problem and proposing a solution on the fly. Candidates report these rounds, while Palantir’s published interview guides do not include one.Source 1FDE Interview Experience at Google (L4)PublisherBlind (teamblind.com)Source typecandidate report on BlindSource 3Kong PS / Forward Deployed Engineer — Take-Home ExercisePublisheralexscottan (GitHub)Source typecandidate’s take-home repositorySource 5Palantir Careers | Getting HiredPublisherPalantirSource typecompany hiring pageSource 8FDE Interview Prep QuestionPublisherBlindSource typecandidate report on Blind

Where have candidates reported customer role-plays in FDE interviews?

Mostly candidate reports: Palantir’s published interview guides include no role-play. One brief from the hiring side, a public repo from a GitHub organization named Axium Industries, describes a 60-minute session in which an interviewer plays the customer. One Google FDE candidate reported, in July 2026, a system architecture round run as a role-play with the interviewer as a company’s CTO. A candidate repo from September 2026 describes a Kong take-home that opens with a kickoff call where the interviewer plays a customer stakeholder.Source 1FDE Interview Experience at Google (L4)PublisherBlind (teamblind.com)Source typecandidate report on BlindSource 3Kong PS / Forward Deployed Engineer — Take-Home ExercisePublisheralexscottan (GitHub)Source typecandidate’s take-home repositorySource 5Palantir Careers | Getting HiredPublisherPalantirSource typecompany hiring pageSource 7Second-stage interview — Forward Deployed Engineer (AI)PublisherAxium Industries (GitHub organization)Source typecompany hiring page

How do I prepare for a customer role-play interview?

Rehearse out loud with someone who plays a customer and holds facts back until you ask. Practice opening with questions about the outcome they need, restating it, proposing a small first version, and offering options with trade-offs instead of promises you cannot keep.

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