Field Guide to Trauma-Informed Software Architecture or Field Guide to Local-First Health Data Privacy

The Overton Framework established Protective Computing as a systems-engineering discipline designed for conditions in which the Stability Assumption does not hold. The Stability Assumption presumes continuous connectivity, cognitive surplus, institutional reliability, non-adversarial access, and predictable infrastructure. In practice, many real-world environments violate these conditions. Systems are frequently used during illness, displacement, coercion, financial instability, legal exposure, disaster, or institutional delay. Under such conditions, conventional architectural assumptions become liabilities. This Field Guide constitutes the operational translation of that foundational theory. It does not extend the theoretical framework. Instead, it defines the engineering posture required to build systems that remain functional, protective, and structurally sound under vulnerability states. Canon Layer: Operational Translation (Layer 2 of the Protective Computing Canon — Core Documents v1) The purpose of this document is to establish a practical baseline for systems design under instability. It formalizes a protective architectural stance oriented toward containment, reversibility, and sovereignty rather than optimization for growth, engagement, or data extraction. The guide articulates five core protective principles: • Local Authority — Decision authority must reside with the user. Remote gatekeepers, centralized dependencies, and hidden escalation paths introduce structural fragility under stress. • Reversibility — Irreversible actions become catastrophic when cognition is impaired or infrastructure is unstable. Protective systems must default toward undoability and safe rollback. • Exposure Minimization — Surface area is liability. Data persistence, transmission, and third-party integrations expand risk under adversarial or degraded conditions. • Cognitive Load Awareness — Systems must be operable at a user’s lowest functional capacity. Design must assume fatigue, panic, distraction, or reduced executive function. • Coercion Resistance — Devices and environments cannot be presumed private. Protective systems must anticipate compelled disclosure, surveillance, or shared access scenarios. Beyond principle articulation, this guide establishes a trajectory toward empirical maturation. It calls for case studies, field validation, and measurable evaluation frameworks. It outlines forthcoming operational artifacts including the Protective Legitimacy Score (PLS) rubric, Design Patterns v0.1, an Implementation Companion, and structured Threat Modeling Templates. This publication forms part of the Protective Computing Canon — Core Documents v1, alongside: • The Overton Framework (v1.3) — Foundational Theory• Protective Legitimacy Score (PLS) v1.0-rc1 — Measurement and Audit Framework Together, these documents establish the theoretical, operational, and evaluative foundations of Protective Computing as a formal discipline. This Field Guide serves as the operational companion to The Overton Framework: Protective Computing in Conditions of Human Vulnerability (DOI: 10.5281/zenodo.18688516).