Add a contact to a segment

Add a contact to a segment

Adds an existing contact, found by ID or email address, to a segment that broadcasts can target.

Note: The contact must already exist; to put a new contact in segments, pass segments when you create it.

Set up

Use the first option your agent supports.

MCP (official, remote)

Add this server to your agent's MCP settings, then sign in when asked.

{ "mcpServers": { "resend": { "url": "https://mcp.resend.com/mcp" } } }

Call the MCP tool add-contact-to-segment.

Server URL: https://mcp.resend.com/mcp

CLI (official)

Install the command, then confirm it runs.

npm install -g resend-cli
resend --version

Run resend contacts add-segment.

Set $RESEND_API_KEY in your environment first (get a key: https://resend.com/api-keys).

API (official)

• Base URL: https://api.resend.com
• Endpoint: POST /contacts/{contact_id}/segments/{segment_id}
• Auth: send the header Authorization: Bearer $RESEND_API_KEY
• Get a key: https://resend.com/api-keys
• Docs: https://resend.com/docs/api-reference/introduction

Before anything else, confirm access with the cheapest read-only call, like a list or a search. Never send or change anything to test access.

Rules

• Ask the user before anything that sends messages, costs money, or changes data, and say how many records it touches. One approval covers a batch the user has seen.
• Never print API keys.