External Coherence & Realizability Verification Protocol (ECR-VP) This document specifies a formal protocol for the independent verification of large, complex architectural corpora describing long-horizon adaptive systems. The protocol is not intended to validate theoretical truth, prove mathematical correctness, or confirm implementation fidelity. Instead, its purpose is to assess structural coherence, readability without author mediation, clarity of architectural boundaries, and the practical realizability of the declared engineering core, while explicitly distinguishing between what is specified, what is constrained, and what is intentionally left undefined or protected as intellectual property. The protocol addresses a recurring failure mode in complex system research and deep-tech architecture development: the inability to determine whether an architectural corpus is coherent, interpretable, and realizable by external parties without relying on the author’s presence or implicit guidance. ECR-VP formalizes a process in which multiple independent interpreters analyze the same fixed corpus under strict isolation and non-causal conditions, producing structured reports that reveal convergence, divergence, and zones of misunderstanding across interpretations. ECR-VP treats language models not as arbiters of correctness, but as epistemically diverse observers whose role is to expose how an architecture is read, not whether it is “right”. Agreement between interpreters is not treated as proof, and disagreement is not treated as failure. Instead, the protocol constructs a coherence map that identifies which elements of the architecture are stably communicated, which are interpreted idiosyncratically, and which remain underspecified or opaque. The final authority of synthesis and closure explicitly remains with a human owner or independent expert, preventing optimization, consensus gaming, or implicit delegation of judgment to automated systems. A central feature of the protocol is strict regime separation. Interpretive hypotheses, architectural invariants, engineering realizability, failure modes, novelty claims, and final verdicts are produced in explicitly separated analytical modes. This prevents the common collapse of speculative interpretation into asserted invariants, and blocks the transformation of high-level architectural descriptions into implicit optimization targets. The protocol enforces non-causal observability at the level of verification itself: interpreters receive no feedback, no cross-model context, and no opportunity for iterative alignment with the author or with each other. ECR-VP is designed for use in preparation of whitepapers, grant applications, industrial pilots, and academic formalization efforts, as well as for internal corpus self-verification and long-term drift control. It is applicable to corpora consisting of architectural descriptions, prior-art publications, provisional patent specifications, canonical documents, diagrams, simulations, source code, and explanatory notes. The protocol does not replace experimental validation or mathematical proof, but it provides a rigorous precondition: ensuring that what is claimed can be read, bounded, and evaluated as an architecture by independent observers. Although the protocol is intentionally architecture-agnostic and designed to be reusable across domains, its structure reflects principles developed in the context of long-horizon adaptive system architectures. In particular, the emphasis on non-causal observation, regime separation, boundary enforcement, and identity preservation mirrors the architectural constraints found in PETRONUS-class coherence-preserving adaptive frameworks. In this sense, while ECR-VP is not a validation of any specific system, the internal architecture of the protocol itself embodies the same structural commitments that motivated its original development.