After 25 years of platform-first engineering, vertical slices are the better approach for AI-driven development

Short summary

A 25-year platform engineering veteran argues that building shared infrastructure before features is now wrong because AI agents work best with small, bounded, complete vertical slices. McKinsey data shows 88% of organizations use AI but only 6% see bottom-line impact, with leading teams achieving 3-5x productivity via overnight agentic sprints. Vertical slice architecture gives agents clear boundaries, while horizontal platforms force agents to load irrelevant context across scattered folders.

• •60% of six-month roadmap features are obsolete by launch; platform-first delays amplify this waste
• •AI agents need small, bounded, complete tasks — vertical slices provide this, horizontal platforms don't
• •McKinsey reports leading orgs see 3-5x productivity with 60% smaller teams using overnight agentic sprints

Generated with AI, which can make mistakes.