The Bottlenecks for AI-Driven System Design: why Principals are not yet obsolete

A veteran systems designer argues that correctness, simulation, verification and performance optimization are no longer the main obstacles to agents building systems like S3 from scratch, but evolution is: migration, frangibility, entropy and the diversity barrier in simulation remain hard. The post suggests abstraction as the human strategy for managing that complexity, and notes that LLMs reason through language while abstractions are often not precisely expressible in it. It concludes that the shift to agents in system design will come when AI invents a novel, useful abstraction for its own use.