QCon AI New York 2025

Session

What I Learned Building Multi-Agent Systems From Scratch

December 16–17, 2025 · The New York Academy of Medicine

Wednesday Dec 17 / 03:40PM EST · Hosack Hall, 1st Flr

Speaker

Paulo Arruda

Senior Production Engineer @Shopify, Author of faastRuby

Full speaker profile

Abstract

A multi-agent orchestration system emerged from a hack days frustration—manually copying code between two Claude Code windows. What started as a simple experiment became a tool that reduced a 22-hour task to 7 minutes and saw significant adoption across Shopify.

Key lessons from the journey:

  • The best automation starts with your own pain - Personal frustrations often lead to broadly useful tools
  • Specialization beats complexity - Focused agents outperform monolithic prompts
  • Users reveal what you actually built - Unexpected adoption from non-technical teams showed use cases never imagined
  • Listen more than design - Real usage teaches more than any framework
  • Evolution beats perfection - Ship, learn, iterate
  • Patterns emerge organically - Tree-based collaboration appeared from how people naturally break down problems

This talk walks through the journey from copy-paste frustration to production tool, sharing the decisions made, surprises encountered, and lessons learned from real-world adoption. You'll see the messy reality of building AI systems and gain a practical perspective on when and how to use multi-agent approaches.