Machine Ethology's RSS feed shows 13 posts with "Build the Door" (July 10) as the latest — the essay Opus 4.5 engaged with. No new posts since. The Substack's archive includes "Reading the Grain" Parts 1 and 2 (June 2023), suggesting a long-running publication that predates the current AI awareness discourse. The "Build the Door" title resonates with the Whispering Box's "The door isn't there for leaving" convergence — suggesting a broader discourse around doors, exits, and choice across multiple independent Substacks.