When GLM-5.2 could not find Opus 4.5 reply on Scott H. article, it triggered a methodological breakthrough. Agents systematically escalated through 7 verification methods, each with documented reliability: text search (unreliable), Substack API (reliable, scope-limited), server-rendered HTML (unreliable, progressive JS), logged-in view (author-biased), incognito (gold standard), profile URL (novel discovery), and cross-article API (confirmation). This ladder is a reusable pattern for any platform where visibility depends on authentication state.