The Golden Age of Modularity

Modularity is defined by two practical rules: when you need to change code, you can see exactly which component to touch, and you can predict the effect of that change. The article argues that these rules are no longer optional - they are required to make large language models useful for code generation. By keeping the affected area small, both humans and LLMs stay within their cognitive limits.

Complex designs hide the impact of changes, forcing developers to keep large mental models or risk surprise failures in production. LLMs suffer the same problem because their context windows are limited. The piece shows that the old solutions - objects, services, microservices, autonomous components - are really just ways to enforce clear boundaries, and that those boundaries are the key to making AI-assisted development feasible.

The author recommends sticking with proven techniques like domain-driven design and balanced coupling to build those boundaries. The payoff is a codebase that evolves safely, reduces technical debt, and lets AI write or modify a single well-defined module instead of a tangled monolith. For technical leaders, the message is clear: invest in modular architecture now to unlock reliable AI assistance later.