no metadata for the SP

[Tom Scavo]

When the IdP receives an AuthnRequest at a SingleSignOnService
endpoint, the IdP consults metadata before interacting with the user.
AFAIK, if the IdP lacks metadata for the SP, the transaction fails
outright, without even presenting the login interface to the user. In
this case, the user is stranded at the IdP, with no chance for either
party to recover.

My question is: Can the IdP be configured to respond with a SAML error
if there is no metadata for the SP? If so, how?

Thanks,

Tom