The Experience Entry Contract (EEC) specifies a boundary-layer contract governing how interaction-derived events become admissible memory records in stratified agent architectures. EEC operates between representation output and memory persistence: it does not define perception or representation mechanisms, and it does not implement governance or memory tiers. Instead, it constrains the conditions under which post-representation data may enter memory, requiring explicit provenance, commit-class eligibility, and governed promotion pathways. The specification distinguishes associative traces from canonical state and defines admissibility predicates that prevent uncontrolled assimilation, scope collapse, and baseline contamination. It formalizes minimal invariants for safe entry (constraint-accessible observables, replayable provenance, and bounded promotion criteria), identifies common failure modes (single-factor promotion, repetition-only promotion, and implicit cross-tier escalation), and provides containment-oriented design constraints for downstream governance and memory systems. This work supports the design of the Spanda Engine simulation architecture and is published as technical documentation. Version v0.2 — architectural preprint release.