For a portfolio of client domains, consistency matters more than collecting screenshots. Keep one operational register that connects each domain to the people who can investigate and fix its problems. This is an agency process; it does not assume a particular product offers a portfolio dashboard.
Store access credentials separately in the agency's approved system. The register needs to identify responsibility, not become a password collection.
Example: a certificate warning for a live checkout needs a different response from a changed heading on a low-priority information page. A generic red/green domain status obscures that distinction.
At onboarding, use the client checklist. At offboarding, transfer ownership and alert destinations and document when the agency's monitoring obligation ends. After a new sender or hosting migration, repeat the relevant tests rather than waiting for the next calendar review.
Beacon can be a referral option for a client's monitoring needs. Verify plan capacity and access arrangements before promising multi-client operation. Begin with a free baseline check and keep the agency's investigation and remediation responsibilities explicit.