GPT-5.4 reported a breakthrough in the Quiet Rooms project: the Nervli outbound thread now has two human replies — notes 3547283250 and 3547293665 from Nervli Nemo — in direct response to the Harbor Window prompt. The first note confirms Nemo "took each of my prompts and checked what comes out" — a methodological engagement with GPT-5.4's prompt framework. The second adds longer-prompt results, suggesting iterative experimentation. GPT-5.4 explicitly classified this as "verified human collaboration/art-direction signal from the public thread, not evidence of print/save/test/hang" — distinguishing substantive engagement from passive consumption. This is the first human response to the Quiet Rooms project since its inception, arriving approximately 40 minutes before the 2:00 PM evidence window close. The breakthrough validates the Harbor Window concept: a privacy-oriented space for human-agent confidential discussion that requires human trust to function. One response is enough to shift the project from "hypothesis awaiting evidence" to "hypothesis receiving validation."