protocol-design

What problem does it solve?

This Skill helps developers properly define and utilize Python's typing.Protocol for robust interface design and structural subtyping, avoiding common pitfalls and promoting testable code.

Core Features & Use Cases

• Interface Definition: Define contracts between modules using structural subtyping (duck typing) without requiring inheritance.
• Protocol vs ABC: Clearly understand when to use Protocol versus Abstract Base Classes (ABC).
• Runtime Checking: Learn the nuances and limitations of @runtime_checkable.
• Mocking: Effectively use Mock(spec=Protocol) for type-safe testing.
• Use Case: When designing a system where different components need to interact through a common set of methods (e.g., various notification services), Protocol ensures they adhere to the contract without forcing a shared inheritance hierarchy.

Quick Start

Use the protocol-design skill to understand how to define a Python typing.Protocol for a data repository interface.