unity-pattern-facade

name	unity-pattern-facade
description	Facade
category	unity
source	unity-design-patterns-skills
source_path	patterns/facade/SKILL.md

Facade

Purpose

Expose a small task-focused API over a complicated subsystem.

Use When

• A subsystem requires repeated multi-step workflows.
• Most callers only need the common path.
• Cross-cutting validation or logging should be centralized.

Avoid When

• You are only renaming a couple of methods.
• Callers genuinely need fine-grained control over every subsystem piece.

Unity Implementation Recipe

1. Identify common workflows.
2. Design methods around those workflows, not subsystem class names.
3. Keep the common path obvious.
4. Document side effects and error handling.

Common Pitfalls

• A facade that grows into a god service.
• Hiding important failure cases from callers.

Minimal Unity Sketch

public sealed class SaveGameFacade
{
    private readonly SaveSerializer _serializer;
    private readonly SaveStorage _storage;

    public SaveGameFacade(SaveSerializer serializer, SaveStorage storage)
    {
        _serializer = serializer;
        _storage = storage;
    }

    public void Save(PlayerProfile profile)
    {
        var json = _serializer.ToJson(profile);
        _storage.Write("profile.json", json);
    }
}

Response Shape

• Say whether Facade is actually the right fit.
• Map it to concrete Unity types, ownership, and lifecycle.
• Prefer a production-shaped skeleton over a long tutorial dump.
• Call out the simpler alternative if this pattern would be overengineering.