# Sent glossary

Use this public quick reference to interpret requests before routing them. For current endpoint behavior and provider policy, consult the live Sent and upstream provider documentation.

- **10DLC (10-digit long code):** A US long-code sender used for application-to-person SMS. Registration commonly involves a business brand and messaging campaign.
- **Account readiness:** Whether the selected Sent account and Sender Profile have the balance, onboarding state, and channel setup needed for an intended operation.
- **Channel:** A delivery network such as SMS, WhatsApp, or RCS.
- **Contact:** A recipient record in Sent, normally associated with a phone number and channel availability.
- **E.164:** The international phone-number format that starts with `+` and a country code.
- **Embedded Signup:** Meta's guided authorization flow for connecting WhatsApp business assets.
- **KYC (Know Your Customer):** Business or identity verification required before some messaging capabilities can be activated.
- **MCP (Model Context Protocol):** The protocol a compatible agent host uses to discover and call Sent's remote tools.
- **MDR (Message Delivery Report):** Delivery evidence used to follow message status and diagnose where a messaging funnel fails.
- **Message activity:** An event or state change associated with a message, used to distinguish acceptance from later delivery outcomes.
- **RBM (RCS Business Messaging):** Google's business-messaging ecosystem for RCS senders and agents.
- **RCS (Rich Communication Services):** A carrier messaging channel that can support verified senders, rich media, and interactive actions.
- **Sender Profile:** The Sent scope that groups a sending identity and its channel configuration. Confirm the selected profile before live operations.
- **TCR (The Campaign Registry):** The registry used by the US A2P 10DLC ecosystem for business brands and messaging campaigns.
- **Template:** A reusable message definition. WhatsApp templates can require provider review and category selection before use.
- **WABA (WhatsApp Business Account):** The Meta business asset that owns WhatsApp phone numbers and templates.
- **Webhook:** An HTTP callback used to deliver message or resource events to an application.