Application Architecture

Default to the simplest structure that works. Add architectural patterns only when complexity demands them -- not before.

Every decision tree below starts with a YAGNI gate. If the gate tells you to stop, stop. Patterns exist to manage complexity; applying them to simple systems creates the complexity they were designed to solve.

Read the relevant reference file when you need deeper trade-off analysis, criteria, and pseudocode examples.

Architectural Smell Table

When reviewing existing code, use this table to identify which decision point is relevant. A smell is not always a problem -- check the YAGNI gate before recommending changes.