The Spec Is the System of Record: Portable Prompts as Cross-Model Artifacts in Enterprise AI — A CharlotteOS Field Study

Enterprise AI adoption has converged on a familiar pattern: an organization sanctions a single assistant, while its practitioners quietly work across several. This paper proposes a third response to that gap, beyond prohibition or pretense: treat the specification — not the conversation, not the artifact — as the system of record. When an iterative build is compressed into a tool-agnostic specification covering source-data quirks, deterministic transformations, plain-language metric definitions, locked visual standards, and a numerical parity check, the result is a portable prompt that any sufficiently capable model, including an organization's officially sanctioned one, can execute and verify. The paper documents a field study: an interactive capital-planning dashboard developed through eleven stakeholder-driven iterations in a single working session, then compressed into a rebuild prompt, generalized into a reusable template, and validated as executable in the organization's sanctioned assistant. The parity check functions as a cross-model contract, converting "did the AI do this correctly?" from a matter of trust into a matter of arithmetic. The paper argues that governance should regulate the artifact, not the keyboard: a sanctioning regime that demands spec-and-parity delivery achieves auditability and institutional continuity, while a regime that demands single-tool purity achieves neither purity nor visibility.