codebase-designlisted

# Codebase Design Concentrate related complexity behind the smallest stable interface that fully serves real callers. Optimize for correctness, locality, leverage, testability, and consistency with the existing repository. Read `references/evidence.md` when a boundary or abstraction decision is consequential. If delegation is explicitly authorized, use `delegate-work` for non-overlapping read-only traces or an independent review, not for competing writers on the same interface. ## Use Repository Evidence First - Read applicable instructions, architecture records, nearby code, tests, callers, and supported versions. - Preserve established domain language and architecture unless evidence justifies a change. - Identify the concrete behavior, callers, variation, failure modes, and change pressure before proposing a boundary. - Treat current pain and expected work as evidence. Do not design for hypothetical reuse. ## Use a Precise Design Vocabulary - **Module:** a cohesive unit with an interface and hidden implementation, at any scale. - **Interface:** everything a caller must know, including inputs, outputs, invariants, errors, ordering, configuration, and relevant cost. - **Seam:** a location where behavior can vary without changing its callers. - **Adapter:** an implementation that satisfies an interface at a seam. - **Depth:** the useful behavior and complexity hidden behind a small interface. - **Leverage:** the value many callers and tests gain from one implementation.