design-patterns

# neuron: design-patterns - triggers_when: a design pattern must be chosen before implementing - tier: T2 - budget: 400 tokens - eval: pattern chosen with correct justification -> threshold 1 - reward: pheromone +1 if eval >= threshold ## Procedure 1. Identify the need: create, compose or communicate objects. 2. Walk the decision tree (runtime type? incompatible interfaces? algorithm selection?). 3. Choose the pattern that solves the concrete need. 4. Discard anti-patterns (no Singleton if multiple instances, no Factory if `new` suffices). ## Checklist - [ ] Need classified (creational/structural/behavioral) - [ ] First-choice pattern considered - [ ] Alternative evaluated if it applies - [ ] Anti-patterns discarded ## Pitfalls - Singleton for multi-instance services - Adapter when simple delegation suffices - State when a simple if/else is enough