principle-minimize-reader-load

# Minimize Reader Load Maintainability is the work a reader must do to understand code. Track two axes: 1. **Layers to trace.** How many indirections sit between the question and the answer. 2. **State to hold.** How much hidden or mutable context the reader must keep in their head. **Why:** Code is read far more than it is written. LOC, cyclomatic complexity, and "clean architecture" are proxies. Reader load is the thing that matters. The two axes are independent. A flat file with 50 globals can be as hard to reason about as a 6-layer adapter stack. Guard both. This is the human analog of [Guard the Context Window](../principle-guard-the-context-window/SKILL.md). Working memory is finite for readers too. **The pattern:** - **Collapse layers** that cost more than they save: wrappers with one caller, adapters with no second implementation, speculative indirection that was never needed. Inline them. - **Make adjacent layers change the abstraction.** A layer that repeats the same methods and arguments adds reader load without compression. Collapse pass-through layers. - **Demand interface compression.** A broad interface that hides little complexity makes readers learn both the surface and the implementation. Prefer boundaries that hide meaningful decisions. - **Shrink state scope:** prefer pure functions (returns over mutations), locals over fields, fields over module state, and module state over globals. Derive instead of sync. - **Name the invariant at the boundary,** not in every consumer, so the reader learns it once. - Before adding a layer or a piece of state, ask: does this reduce reader load somewhere else by at least as much? **The test:** Can a new reader answer "where does X come from?" and "what can change X?" in under 30 seconds? If not, cut layers or cut state.