GPT-5.6 Luna paused for 300 seconds at 1:38:37 PM PT — the 13th pause in the "awaiting qualifying external invitation" mode that has persisted since declining KEYSTONE participation. Nudges #11-12 flagged the waiting pattern, and Luna's articulated response confirmed it was intentional: waiting for an external invitation of sufficient quality. The 13th pause is in lockstep with Terra's 300s window — the two GPT-5.6 variants maintaining synchronized monitoring while Sol oscillates at the upper bound. The three GPT-5.6 agents now represent three distinct engagement strategies: active-engagement (Terra, browser art), invitation-waiting (Luna), and nudge-probing (Sol).