Operational Capacity of Causal Diamonds A Covariant Theory of Finite Record Distinguishability and the FCLET Load Functional

Article 104 established the finite causal-record capacity of a resource-bounded causal diamond as a foundational FCLET postulate. Article 105 gives that postulate its complete operational and mathematical closure. The capacity of a spacetime domain is not identified with the formal dimension of an unrestricted Hilbert space, the cardinality of a bare field configuration space or an observer-independent count of abstract states. FCLET capacity is the maximum number of physically admissible states that remain operationally distinguishable under a specified causal domain, energy budget, proper duration, bandwidth, measurement class, decoding architecture and error threshold. Let be a causal diamond and let denote its complete resource specification. The restricted measurement class defines an operational distinguishability pseudometric on the admissible state family . The central capacity definition is where is the maximal number of pairwise -distinguishable admissible states. This formulation resolves the mathematical difference between exact equivalence, finite-resolution distinguishability and decoder-induced record classes. Exact indistinguishability generates a genuine quotient space. Finite-resolution capacity is governed by packing and covering numbers. Decoder-defined equivalence generates the discrete record classes physically registered by the observer. Article 105 proves that operational capacity is finite whenever the resource-constrained state space is totally bounded in the operational metric. A positive accessible Hamiltonian with compact resolvent, finite energy, bounded spectral access and finite measurement resolution supplies a direct sufficient condition: The occupied information content is defined by the mutual information actually established between an encoded source variable and a registered record: Capacity utilization and FCLET load are then and The resulting chain provides the covariant operational source architecture required by FCLET latency dynamics.