Cryptographic Validity Is Not Runtime Admissibility: Opaque Reasoning Traces, Dynamic Classification Failure, and a Synthetic Policy-Conformance Benchmark

Encrypted reasoning traces exposed a broader architectural error in agentic memory: cryptographic authenticity does not establish contextual, semantic, or operational authority. This working paper formalizes a Contextual Runtime Admissibility Gate (CRAG) and reports a deterministic 28-case synthetic policy-conformance benchmark with a 14-case combinatorial holdout. Context binding alone admitted 60% of unsafe cases overall and 70% on holdout. Full CRAG admitted none while preserving all eight benign-continuity cases. The result establishes conformance to a frozen author-defined normative contract, not independent construct validation or production effectiveness. The deposit includes the paper and the complete synthetic replication package.