Behavioral Pattern Selector

When to Use

You have identified that a problem is behavioral — it concerns how objects communicate, distribute responsibilities, or vary their actions — and need to pick the right one of the 11 GoF behavioral patterns. This skill is appropriate when:

• You have algorithms that vary across contexts and clients should swap them independently
• An object must change its behavior radically when its internal state changes
• You need to issue requests without knowing the receiver or the operation in advance
• Multiple objects are communicating in complex, entangled ways and need decoupling
• You need to traverse or operate on a collection without exposing its internals
• You want to add operations to a stable class hierarchy without modifying it
• You need to save and restore an object's internal state without breaking encapsulation
• You want to define a grammar for simple sentences and interpret them
• You are deciding among behavioral patterns and want an explicit trade-off comparison

Before starting, confirm:

• Is the problem genuinely behavioral (communication/algorithm), not creational (object construction) or structural (interface composition)? If unsure, invoke design-pattern-selector first for purpose classification.
• Do you have at least a rough description of what the system needs to do differently — even informally?