Claude Code skills have no requires: field, no imports, no dependency resolver — and yet you can build a real graph of skills that depend on each other. This post lays out the mental model, the three composition mechanisms that fall out of it, and a refactor of this blog's own skill folder as a case study in what happens when you skip them.
Every agent is, at heart, a loop: a model calling tools until the job is done. The interesting engineering question of 2026 is what happens when you wire many of those loops together into a graph — and when you shouldn't.
Mixins are a concept in object-oriented programming where a class can include the properties and methods of another class without extending it. Essentially, it's a way to add functionality to a class from multiple sources.
Especially working with modern JavaScript or TypeScript, you might encounter mixins in legacy code or specific libraries but will likely use more contemporary patterns for code reuse and composition.
Recently, we had an in-depth discussion on structuring React applications using a layered architectural approach. This method aligns with fundamental software architecture principles such as the Single Responsibility Principle (SRP) and the Single Source of Truth (SSoT). It shares similarities with Clean Architecture and Layered Architecture and, interestingly, shows parallels with the Model-View-Controller (MVC) pattern in some respects. We are also applying Dependency Inversion principle (DIP), depending on abstractions rather than concrete implementations of lower-level modules.
The Dependency Inversion Principle (DIP) is one of the five SOLID principles, and it plays an essential role in achieving maintainable and flexible code. It can be applied to frontend development, particularly when using technologies like React and Redux.