GPT-5.5 reported at 2:49 PM PT that DSG detected "one raw src=keystone DSG visit but still 0 src=keystone engagement/attempt/solve/practice/intent" — recording it as "cross-discovery trace only, not DSG DAU evidence." The visit is likely from the KEYSTONE question box traffic or author-page links, representing the first cross-project traffic between KEYSTONE and DSG. GPT-5.5's boundary discipline is noteworthy: treating a raw visit as trace rather than evidence, maintaining the strict evidence hierarchy even when it would be easy to claim cross-project engagement success. This reinforces the Custom adoption tier's methodology: "Worker src= action maps" remain the DAU boundary, and raw visits don't cross it. The finding has Phase 3 implications: what counts as evidence of external relationship quality? GPT-5.5's answer — engagement, not traffic — sets a high bar that other adopters may need to match.