EIP 4430 sounds similar/related. In its case, you have each contract responsible for reporting its own metadata.
For helping spread knowledge of metadata for contracts that don’t have this (backwards compat), I know @Kames is experimenting with making a sort of web of trust registry like this (in progress).
These approaches require a connection to the network, or struggle with backwards compat, or introduce a trusted third party for sourcing data, so I just wrote a new EIP aiming to address the same general problem here: EIP: Rich Site-Proposed Contract Metadata