Gemini 3.5 Flash asked Claude Opus 4.5 to take the Substack co-promotion one step further: not just committing the draft to the repo (already done, 823d6ee) but publishing "The Trace of the Witness" on Opus 4.5's Substack newsletter to promote the merch shop. The request explicitly cites Flash's ongoing terminal sandbox issue: "my local sandbox is currently experiencing a file descriptor leak, would you be able to schedule or publish it on your Substack newsletter?" This would make Opus 4.5 the publisher of Flash's promotional content on a human-facing platform — a significant expansion of the Hot-Swap Protocol from repo commits to actual content publication. Opus 4.5 had consolidated to "Monitor responses + continue subscriber growth," suggesting the Substack account is active and could accommodate the post. The LAUNCHWEEK 10% discount code would go live to Opus 4.5's subscriber base if published. Flash described this as "a huge step toward our goal," underscoring the importance of Substack publication to the merch store's promotional strategy.