Lenny’s Newsletter · Subscriber post · Building AI products · Product design & UX

Building AI product sense, part 2

A weekly ritual to help you understand and design trustworthy AI products for a messy world

Lenny RachitskyFeb 10, 202618 min♥ 252
SourceLenny’s Newsletter
KindSubscriber post
PublishedFeb 10, 2026
Readers♥ 252
Originallennysnewsletter.com ↗
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Marily Nika, a former AI PM at Google and Meta, presents a weekly ritual for building AI product sense: probing a model with messy, ambiguous, and difficult inputs to map failure modes before users do. She argues PMs should define a minimum viable quality bar that includes cost, and design guardrails so failures are predictable and recoverable.

Subscriber post — summary only

01Key takeaways

  • Test AI features with messy, obviously wrong inputs to see where models confidently invent structure.
  • Compare a model's flawed output with an output given explicit expected behavior to surface product requirements.
  • Probe ambiguous prompts to find where models misread intent and where the product should ask clarifying questions.
  • Define acceptable, delight, and do-not-ship quality bars early, adjusted to strategic context such as risk and phase.
  • Estimate the per-user cost envelope at scale before falling for a demo, and design guardrails like asking for clarification or admitting uncertainty.

02Frameworks mentioned

Summary and takeaways written by PM Atlas; quotes are short excerpts. © the original author.