Adding Configurable Rules and AI Steps to a Hard-Coded Workflow Engine

Quick Overview

A product and system design question for a product manager interview at Stitch about evolving a hard-coded, deterministic workflow system into one that users can configure and that uses AI. It tests where AI belongs, how changes are validated and versioned, auditability, human review and phased rollout.

Adding Configurable Rules and AI Steps to a Hard-Coded Workflow Engine

Company: Stitch

Role: Product Manager

Category: System Design

Difficulty: medium

Interview Round: Other

Picture a workflow system whose steps are defined in code and always run the same fixed, deterministic way. As a product manager, how would you approach making it more configurable and adding AI capabilities to it? ```hint Decide what must stay deterministic Some steps can tolerate an answer that is usually right; others, such as anything that moves money or makes a compliance decision, must give the same result every time. Sort the steps before deciding where AI goes. ``` ### Clarifying Questions - Who should be able to change a workflow: internal operations staff, engineers, or the business clients whose processes run on it? - What kinds of processes does the system run today, and which steps move money or make regulated decisions such as identity or fraud checks? - What is prompting the change: a backlog of engineering requests for workflow edits, a growing manual review queue, or clients asking for custom logic? - What audit and explainability obligations apply to the decisions a workflow makes? ### What a Strong Answer Covers - A diagnosis of who is held back by the hard-coded system, and how, before any solution is proposed. - A configuration model: how workflows are defined, validated, tested, versioned and rolled back, and who may change what. - Where AI adds value and where deterministic logic must remain, with human review, confidence thresholds and fallbacks for AI steps. - Reliability, auditability and reproducibility of runs that include AI steps, including model outages and cost. - A phased rollout with success metrics and guardrails. ### Follow-up Questions - An AI step and a fixed rule reach different conclusions on the same case. Which one wins, and who sets that policy? - A configuration change breaks a live workflow for several hours. What should have prevented it or limited the damage? - How would you let a user describe a new workflow in plain language and have AI draft it without weakening safety?

Overview: A product and system design question for a product manager interview at Stitch about evolving a hard-coded, deterministic workflow system into one that users can configure and that uses AI. It tests where AI belongs, how changes are validated and versioned, auditability, human review and phased rollout.

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Stitch
Aug 15, 2026
mediumProduct ManagerOtherSystem Design
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Picture a workflow system whose steps are defined in code and always run the same fixed, deterministic way. As a product manager, how would you approach making it more configurable and adding AI capabilities to it?

Clarifying Questions Guidance

  • Who should be able to change a workflow: internal operations staff, engineers, or the business clients whose processes run on it?
  • What kinds of processes does the system run today, and which steps move money or make regulated decisions such as identity or fraud checks?
  • What is prompting the change: a backlog of engineering requests for workflow edits, a growing manual review queue, or clients asking for custom logic?
  • What audit and explainability obligations apply to the decisions a workflow makes?

What a Strong Answer Covers Guidance

  • A diagnosis of who is held back by the hard-coded system, and how, before any solution is proposed.
  • A configuration model: how workflows are defined, validated, tested, versioned and rolled back, and who may change what.
  • Where AI adds value and where deterministic logic must remain, with human review, confidence thresholds and fallbacks for AI steps.
  • Reliability, auditability and reproducibility of runs that include AI steps, including model outages and cost.
  • A phased rollout with success metrics and guardrails.

Follow-up Questions Guidance

  • An AI step and a fixed rule reach different conclusions on the same case. Which one wins, and who sets that policy?
  • A configuration change breaks a live workflow for several hours. What should have prevented it or limited the damage?
  • How would you let a user describe a new workflow in plain language and have AI draft it without weakening safety?