Currently, we disallow complex attribute value types as part of standard attributes. However, some users have requested we relax this restriction. Specifically, this issue was re-opened in the 3/11/25 Specification SIG meeting in the context of Generative AI semantic conventions, and the suitability of Events vs. Attribute Values for representing certain metadata on a span.

While this issue has been discussed in the past, I think it behooves us to provide guidance around JSON String encoding for values for semconv and consumers.