function-design

What problem does it solve?

This Skill codifies Python function design conventions for this codebase. Apply when writing or reviewing functions including signatures, parameters, return types, and async patterns.

Core Features & Use Cases

• Explicit dependencies: Pass as parameters, no global state
• Single Responsibility: One function = one task
• Pure Functions When Possible: Return new values, don't mutate inputs
• Guard Clauses: Validate early, return/raise immediately
• Return Type Stability: Same type regardless of input
• Exceptions Over None for Errors: Reserve None for "not found" only
• Command-Query Separation: Action OR data, not both
• Keep Functions Small and Focused: Composed of focused helpers

Quick Start

Use this skill to review Python functions for adherence to the conventions above. For example, ensure each function has a single responsibility, uses explicit dependencies, and returns a stable type.