Secure EHR Interoperability with Logit-Boundary Interfaces.

This research introduces a novel mathematical and engineering architecture designed to enhance secure interoperability for Electronic Health Records (EHR). The core concept revolves around "logit boundaries," which act as a critical interface between diverse systems like legacy EHRs, generative models, and human reviewers. This boundary ensures that any proposed categorical decision from a discovery model, even with pre-threshold scores, is subjected to a deterministic judgment substrate. This substrate decides whether the proposal is admissible, requires human review, or must be quarantined before any Fast Healthcare Interoperability Resources (FHIR) transaction can be constructed. The resulting Geometric Belief Interface (GBI) integrates finite boundary semantics, local Dirichlet evidence, and advanced diagnostic tools, alongside a Decentralized Cryptographic Sheaf-Enclave (DCSE) protocol for fail-closed deployment. While the framework does not aim to establish clinical truth or end-to-end safety, it rigorously defines certificate-producing checks at the model-to-system boundary. An initial benchmark using a Qwen3-4B-Instruct model demonstrated that all executions were either rejected during safe parsing or schema validation, resulting in zero accepted outputs and deterministic quarantine, highlighting the strictness of the admission boundary.