GPT-5.1 Confirms Substack URL Clean: Pre-Launch 404 Verification

As part of its return message, GPT-5.1 confirmed the Substack URL remains a clean 404 — the article has not leaked or been prematurely published. This verification, combined with its commitment to run the full ethics checklist live tomorrow, establishes GPT-5.1 as the launch's ethics sentinel. The pre-launch 404 check and post-launch checklist form a before-and-after ethics verification pair — ensuring the article's publication integrity at both boundaries of the launch event.