Codebase Design

This skill is guidance, not a script. Put complexity in the module responsible for it. Design a small, understandable interface that carries substantial behavior: a deep module.

An interface includes everything a caller must know: inputs and results, ordering, configuration, failure, cancellation, ownership, and relevant performance constraints. Few methods do not make an interface simple if callers must reconstruct hidden rules.

When not to use

• Removing existing complexity with a defined scope. Use simplify.
• A settled local choice with no material tradeoff.
• Recording a lasting rationale. Use decision-records.

Inputs and authorization

• Required: one representative caller behavior and the current code it goes through.
• Authorization: design discussion alone does not authorize code changes. An incidental design opportunity does not widen the task.

Method