Abstract

We construct a supported local spacetime adaptation of the plateau intertwiner of Manuscript VII-A. The physical background is the regular part of I-B's prescribed conical Lorentzian product, not global Minkowski spacetime. A developing chart supports a precisely specified switched scalar action, unswitched finite-time harmonic coordinates, and formal diffeomorphisms supported inside a switch plateau. We prove the complete second-order scalar and coordinate intertwiners, including the density transformation and every switch derivative, without imposing a field equation on the metric coefficients. The construction restricts to an explicitly defined, nonempty Einstein–scalar coupling jet.

The repair is deliberately relative. For general compact gauge supports we derive the exact first-order residual ${\mathsf{E}}_m{{\mathcal{Q}}_{(1-g)\mathcal{K}\xi }}^{(m)}{\varphi }_0$, construct a strictly negative smeared witness, and prove that no higher coupling coefficient or positive $\hslash$-order removes the fixed classical gap. We also prove causal dependence on the truncated observation past and a unique Cauchy-data-preserving comparison cocycle between switches. An explicit example shows why equality on an observation plateau alone is insufficient.

The additional contribution is a finite operational realization that records both the repaired coefficients and the unrepaired gap. A sourced massless family supplies a nontrivial evaluation table; a complete destructive Enter instrument reads its finite encoding, admits a quantitative complete-channel approximation bound, and transports the payload and its classical control record along a prescribed causal route. This separation of classical covariance, preparation memory, and finite readout may provide a useful reproducible interface for later analytic work. It is not field acquisition or a quantum-gravity measurement construction. The classical plateau gate is closed on the stated domain; no quantum product, quantum Ward identity, radiative coefficient, or counterterm separator is constructed.