Lesson 10 · Customer-Facing Craft

Discovery, Scoping & Demos That Land

The consulting half of the role: find the real problem behind the ask, write a scoping doc that survives contact with reality, demo like the meeting matters — and know when to say "don't build this."

FDE skill · the make-or-break interview round, taught head-on
🎧 Listen to this lesson · ~11 min · narrated audiobook edition

⏱ ~10 min read · 🎧 11 min listen · ✎ 3 quizzes · 🧪 ~90 min lab

Nine lessons of engineering, and here is the uncomfortable truth: the skill that most often decides an FDE interview — and an engagement — isn't any of it. Exponent's analysis of FDE interview loops names the single most common rejection reason: jumping to a solution in the decomposition round.1 The 1,000-posting market analysis found the skill profile shifting toward "a hybrid of technical depth and customer-discovery ability"3 — and recruiters say the translation half of that hybrid is the hardest of all four FDE competencies to find.2 This lesson trains the consulting half of the role: discovery, scoping, translation, demos — and the judgment call the whole course has been building toward.

First, honesty: there is no canonical playbook

Let's be straight about the ground we're standing on. As of mid-2026, no canonical FDE discovery methodology exists — the role is young and its literature is thin. What follows is a synthesis, clearly labeled as such: built from the Exponent interview analysis1, Palantir's founding discipline of identifying the most valuable thing to work on4, practitioner accounts of the engagement day-to-day5, and consulting-adjacent practice like Rob Fitzpatrick's The Mom Test — the standard text on asking customers questions that produce truth instead of politeness.7 Treat it as a strong default, not gospel — and expect to sharpen it against real customers.

Discovery: the ask is not the need

Every engagement starts with an ask: "we want an AI copilot", "we need a chatbot", "can you add RAG to our portal". The ask is a solution the customer has already imagined — and the founding FDE discipline is to treat it as evidence about the problem, not a spec.4 Your job in discovery is to walk the ask backwards to the pain that produced it: who hurts, doing what, how often, at what cost, and what happens if nothing changes. The Mom Test's core rules translate directly: ask about their life, not your idea; ask about specific past incidents, not hypothetical futures; and let them talk — the customer should hold the floor most of the meeting.7

Why "The Mom Test"? Fitzpatrick's title: your mom will tell you your idea is great because she loves you — and customers will tell you your copilot idea is great because you're standing in their office. Good discovery questions are ones even a polite person can't answer with a comforting lie.
Instead of asking…Ask…What it surfaces
"Would an AI copilot help your team?""Walk me through the last time this went wrong."A concrete incident with real steps, systems and people
"What features do you want?""Where does the time actually go in that workflow?"The costliest step — often not the one in the ask
"Is data quality an issue?""Show me the actual data. Can I shadow someone for an hour?"Ground truth — what people do, not what they report
"Any compliance concerns?""What would your regulator or legal team say if we shipped this?"The blocker nobody volunteers until it kills the project
"Would you use this?""If this worked, what number changes, and who tracks it?"The success metric — and whether anyone actually owns it

Decomposition and the scoping doc

Discovery produces raw material; decomposition turns it into an engagement. Break the vague ask into a tree of concrete sub-problems, each small enough to ask three questions of: is it valuable, is it feasible, and — the AI-judgment question — is AI even the right tool for it? Interviewers run this exact exercise as a live round, and the failure mode is always the same: proposing an architecture before the problem is decomposed.1 The written artifact is the scoping doc — the document that converts a conversation into a commitment both sides can hold each other to:

SectionWhat goes in itSmell test
Problem decompositionThe ask, the underlying problems found in discovery, broken into a tree of sub-problemsCould a stakeholder point at the branch that hurts most?
Asked vs neededWhat the customer asked for, what discovery showed they need, and the evidence for the gapIs the gap backed by incidents and numbers, not vibes?
Success metricsEval-shaped, measurable targets per phase — the numbers your evals from Lesson 05 will trackCould you build the eval harness from this section alone?
RisksData access, compliance and privacy, adoption, model-failure modes — with an owner and mitigation eachDoes it include the risk the customer didn't volunteer?
Phased planSmallest valuable phase first, with a go/no-go metric gating each next phaseDoes phase one ship real value in weeks, not months?
Out of scope / not AIWhat you are explicitly NOT building — including anything where AI is the wrong tool, with the reasonIs at least one "we recommend not using AI for X" line in it?
Scope creep's natural enemy The scoping doc is not bureaucracy — it's the thing you point at, kindly, when week three brings "while you're in there, could it also…". New idea? Great: it goes in the tree, gets sized, and trades off against a phase — visibly, on paper, with the stakeholder choosing what it displaces.

Stakeholders and translation

An engagement has more than one customer. Map them early — sponsor (owns the budget and the "why"), end users (own adoption; the clinicians, agents, analysts who must actually change how they work), technical gatekeepers (own access to data and systems), and risk owners (legal, compliance, security — the quietest voices with the loudest veto). Each needs the same truth in a different language, and that skill — translation, trade-offs in non-technical words — is the one recruiters call the hardest of the four competencies to find.2 The pattern: never hand an executive a metric; hand them a decision. Not "our judge-scored faithfulness is 0.92" but: "about one summary in twelve still contains an error a clinician must catch, so we keep a human review step — we can shrink that number, and here's what each point of improvement costs." Metric → consequence → choice.

Demos that land: the meeting is the craft

Lesson 06 taught you to build the demo; this is the meeting craft. Demos that land share five habits. Their data, not yours — a mediocre demo on the customer's real tickets beats a slick one on synthetic data, because recognition is what creates belief. Their words — name the workflow exactly the way the users named it in discovery. One workflow, end to end — depth on the branch that hurts most, not a feature tour. Rehearse the failure — show one case the system gets wrong and how it's caught; the honesty buys more trust than the wins do, and it sets up the AI-judgment conversation. And end on a commitment — a demo lands when it converts into a named next step: these three users, this data access, this date. Remember what an FDE demo is for: unlike a solutions architect, you are not selling the recommendation — you're opening the door to production code on their infrastructure.6

Recommending against AI — and keeping the customer

This is the AI-judgment thread's home lesson. Models are persuasive when they're wrong2 — and so are roadmaps. Some of what discovery surfaces will be problems AI shouldn't touch: deterministic rules pretending to be judgment calls, workflows where one bad output is unrecoverable, automation of a step nobody actually spends time on. Saying so is a skill with a shape. Anchor in their goal: "you want fewer triage errors" — not "your idea is bad". Show the evidence: the eval numbers, the failure cases, the cost per correct outcome from Lesson 09. Offer the boring alternative: often a rules engine, a form redesign, or a reporting fix delivers the outcome for a tenth of the risk. Redirect, don't just refuse: pair every "not this" with the branch of the decomposition tree where AI does earn its keep. Customers don't fire the engineer who saved them from a failed pilot — in a market where roughly 95% of GenAI pilots show no measurable impact3, "we recommend not building this" is the cheapest credibility you will ever buy.

The courage part The hard bit isn't the analysis — it's saying it to someone whose budget, or bonus, is attached to the AI project happening. Write the recommendation down before the meeting. A one-paragraph written case is much harder to argue past than a hesitant verbal one — and it's the artifact this lesson's lab makes you practice.
The mental model in one line Discovery walks the ask back to the pain; the scoping doc walks the pain forward to a phased, eval-gated plan; translation and demos carry every stakeholder along — and AI judgment decides which branches never get built at all.

🧪 Practical steps: the discovery pack (~90 min)

This lab is conversation plus writing, not code. You'll run a simulated discovery conversation against a role-played stakeholder — the Head of Clinical Ops at the same fictional virtual-care provider your Lesson 11 capstone serves — then write the scoping doc. The role-play prompt gives your AI assistant a stressed executive with a vague ask ("we want an AI copilot for our clinicians") and hidden real problems it will only reveal under good questioning, including a compliance worry it won't volunteer at all unless probed. Full instructions and the copyable role-play prompt are in labs/0010-discovery-pack.md.

  1. Start the role-play — paste the stakeholder prompt from the lab file into a fresh chat with any AI assistant. It will play the Head of Clinical Ops and open with the vague copilot ask.
  2. Run discovery (~30 min) — use the question patterns from this lesson: last-time-it-went-wrong incidents, where the time goes, show-me-the-data, the regulator question, what-number-changes. Take notes as you go; don't propose solutions yet.
  3. Draw the decomposition tree — the ask at the root, the real problems you surfaced as branches, sub-problems as leaves, each tagged valuable / feasible / AI-appropriate.
  4. Write asked-vs-needed — one short section: what they asked for, what discovery showed they need, and the evidence for the gap.
  5. Write eval-shaped success metrics — measurable targets per phase that a Lesson 05 eval harness could actually track.
  6. Write risks and the phased plan — including the compliance risk (did you find it? Australian Privacy Act territory), each risk with an owner and mitigation, and a go/no-go metric gating each phase.
  7. Write the "not AI" line — at least one explicit "we recommend NOT using AI for X, because Y — instead do Z" recommendation, in non-technical language.
  8. Save the pack — transcript notes, tree, and scoping doc — to D:\Projects\FDE-Portfolio\l10-discovery-pack\.

Feedback loop: bring the scoping doc back to me in chat with your discovery transcript, and I'll review it like the customer's steering committee would — did your questions earn the hidden problems, does the tree go deeper than the ask, would a non-technical sponsor understand every trade-off? This is the direct rehearsal for the Lesson 11 capstone engagement — the same fictional customer, for real this time — and it's tracked in the course's artifact tracker.

🤖 Get your work reviewed

No chat here — this box replaces it. Copy the prompt into any AI assistant (Claude, ChatGPT, Gemini…), then paste your scoping doc (and discovery notes) after it.

You are a skeptical customer steering committee reviewing a Forward Deployed Engineer's discovery pack for a virtual-care provider. The pack contains: notes from a discovery conversation, a problem decomposition tree, an asked-vs-needed analysis, eval-shaped success metrics, risks (including compliance), a phased plan, and at least one "we recommend NOT using AI for X" recommendation.

Grade each criterion as Strong / Adequate / Missing, with one sentence of evidence:
- Quality of probing questions: the discovery notes show questions about specific past incidents, real data, and unvolunteered risks (especially compliance) — not hypothetical or leading questions that invite polite lies.
- Decomposition depth: the tree goes at least two levels below the original ask, and each leaf is tagged for value, feasibility, and whether AI is the right tool — with at least one branch honestly ruled out.
- Non-technical clarity of trade-offs: every metric and trade-off is translated into consequence-and-choice language a non-technical executive could act on, with no unexplained jargon.

Be adversarial: find the risk the doc missed, challenge the vaguest success metric, and pressure-test the "not AI" recommendation — would it survive a sponsor whose budget depends on the AI project? Finish with the one change that would most improve this scoping doc.

My discovery pack follows below.
🧭 Field practice this week

Check yourself — think like an FDE

Scenarios, not recall. Diagnose from the mental model — don't scroll up. Wrong picks stay live.

Scenario A

FDE interview, decomposition round. The prompt: "A hospital network wants an AI assistant to reduce nurse workload. How would you approach it?" You know this domain cold — you can already picture the agent architecture, the RAG layer, the eval harness. The interviewer waits. What's your opening move?

Scenario B

Week three of a phased engagement. On a status call, the sponsor says: "This is going great — while you're in there, can the copilot also draft patient billing disputes? Should be small." It isn't small: new data source, new risk owner, and phase one's eval targets aren't hit yet. Everyone on the call is looking at you. What's the FDE move?

Scenario C

Your eval harness shows the note-drafting system's judge-scored accuracy went from 0.81 to 0.94 after a month of iteration, but the CFO — who signs the renewal — asks bluntly: "So does this thing work or not?" You have thirty seconds. What do you say?

Primary source — read this
The interview loops at Palantir, OpenAI and Anthropic — including the decomposition round this lesson trains for, and the most common reason candidates fail it. Read it as a mirror: every round is a discovery or translation skill you can now name.
Your one tangible win You've run a discovery conversation that earned hidden problems instead of accepting the ask, and turned it into a scoping doc with a decomposition tree, eval-shaped metrics, and a written "don't use AI for this" recommendation. That pack is the direct rehearsal for the capstone — and the exact artifact FDE interviewers probe for.
Questions? Any AI assistant is your teacher. Not sure whether your decomposition tree is deep enough, or how to word a "not AI" recommendation for a touchy sponsor? Paste the relevant section of this lesson into your AI assistant along with your question — and for the full discovery pack, the review box above has you covered.

Recommended learning

Hand-picked follow-ups. None are required — the primary source above comes first.

References

  1. Exponent, "FDE Interview: The Definitive 2026 Guide" (2026) — the decomposition round; most common rejection: jumping to a solution; "half engineer, half consultant, full owner".
  2. Matt Gold, LinkedIn post on FDE hiring criteria (2026) — problem discovery and translation among four competencies weighed over coding; translation "the hardest of the four to find"; models are persuasive when wrong.
  3. Perspective AI, "2026 FDE Hiring Trends: What 1,000 Job Posts Reveal" (2026) — skill shift toward customer-discovery ability; 95% of enterprise GenAI pilots show no measurable impact.
  4. Palantir, "A Day in the Life of a Palantir Forward Deployed Software Engineer" (2020) — consistently identifying the most valuable thing to work on.
  5. Per Aspera, "How to Build Your 1st FDE Team" (2025) — engagement day-to-day: on-site integrations, user training, days-to-weeks cycles, high autonomy.
  6. Gergely Orosz, "What are Forward Deployed Engineers?", The Pragmatic Engineer (2025) — the FDE/SA boundary: FDEs write production code on customer infrastructure.
  7. Rob Fitzpatrick, The Mom Test (2013) — discovery-question discipline: their life not your idea; specific past incidents over hypotheticals; talk less, listen more.