Admission Decision. The explicit decision that material, evidence, input, artifact, request, or fallback path may cross a boundary into trusted use, model context, execution, or grounding. An admission decision turns "we received it" into "it is allowed here."
Admission decisions depend on context: provenance, trust root, signature, source health, policy, sensitivity, approval, and intended use may all matter. The important architectural move is making admission visible and reviewable instead of letting successful transport, parser success, or local availability silently become permission.