@send0/mcp

@send0/mcp

MCP server for send0. Give Claude, Cursor or any MCP client its own email inbox: sign up for things, read verification codes, and hold real email conversations.

Tools

Tool	What it does
create_inbox	Make a new address, e.g. [e-mail]
list_inboxes	Inboxes this key can use
wait_for_email	Block until a matching email arrives; returns the one-time code and verify link already extracted
search_messages	Full-text search, filter by sender (*@github.com) or direction
get_message	Read one message (new text only by default, to save tokens)
list_threads / get_thread	Read whole conversations, oldest first
send_email	Start a new thread
reply	Answer in the same thread

Email bodies are returned inside <untrusted_email> tags with a note to treat them as data, and messages flagged for prompt injection carry a visible warning. Read-only tools are annotated readOnlyHint, and sending tools openWorldHint, so clients can ask before sending.

Setup

Get an API key at https://send0.dev. A key limited to one inbox is the safest choice for an agent.

Claude Code

claude mcp add send0 --env SEND0_API_KEY=s0_live_… -- npx -y @send0/mcp

Claude Desktop / Cursor

{
  "mcpServers": {
    "send0": {
      "command": "npx",
      "args": ["-y", "@send0/mcp"],
      "env": { "SEND0_API_KEY": "s0_live_…" }
    }
  }
}

Options

Variable
SEND0_API_KEY	Required
SEND0_INBOX_ID	Default inbox, so tools don't need inbox_id
SEND0_BASE_URL	For self-hosted send0

Use it from code

import { createSend0Server } from "@send0/mcp";
import { Send0 } from "@send0/sdk";

const server = createSend0Server({ client: new Send0(process.env.SEND0_API_KEY) });
// connect any MCP transport

License

MIT