Feature request: functional placeholder URLs in signatures

I'd like to use a placeholder URL in the brand or agent signature that will allow the ticket requester to give feedback without us needing to send a follow-up survey or manually add the URLs in the ticket text. 

For example, this is what we want to include as the signature:

GiveDirectly made it easy to answer my question... 

[Yes!]({{satisfaction.positive_rating_url}}) [No]({{satisfaction.negative_rating_url}})

I chatted with support and confirmed that placeholder URLs do not work in signatures.