Abstract: This paper formalizes the "Narrowest-Scope Rule" (NSR), a governance principle for maintaining the integrity of the contract-style-comments (CSC) Triumvirate. NSR provides a deterministic heuristic for artifact selection during system updates, ensuring that operational data, architectural invariants, and teleological reasoning remain logically decoupled to prevent documentation rot and "contextual drift." Jeffrey Sabarese ( @ajaxstardust ) Part III of the contract-style-comments Series I. The Problem: Documentation Entropy In classical development, documentation suffers from monolithic bloat : new information is appended to the nearest visible file, regardless of logical category. In agentic systems, this leads to Context Window Dilution . When an AI agent must ingest a CONTRACT.md cluttered with transient operational details, the signal density of the system's core invariants is diminished. The Narrowest-Scope Rule (NSR) acts as a systemic constraint to preserve signal density.…