The contact
Decide where phone formatting, duplicate detection and the primary contact record live. A messaging provider should not create a second identity every time the same customer replies.
The trigger
Document what starts a send and what prevents it. Include contact status, sequence membership and a human already answering. Keep test contacts clearly separated from production records.
The reply
Choose the inbox where a teammate sees the message and the record that stores it. Write the rule for reassignment and after-hours coverage before connecting a second team.
The failure
Ask where a rejected or delayed send appears. Assign an operator to investigate failed work and make sure replays do not create duplicate messages.
The change
Keep a short record of credentials, configuration owners and support routes in your private operations system. Test a small representative workflow whenever a provider or CRM changes its integration.