SMTP MCP Server

SMTP is an MCP integration. MCP server that sends mail over SMTP, gated behind an allowlist and a human confirmation.

Packages and local setup

The published npm package is @ni-c/smtp-mcp, version 0.2.0. Its declared MCP transport is stdio.

The package declares SMTP_HOST (required): Hostname of the SMTP server, e.g. smtp.example.net.; SMTP_PORT: Port. Defaults to 587 for starttls, 465 for implicit, 25 for none.; SMTP_TLS: starttls (default), implicit or none. STARTTLS is required, never opportunistic.; SMTP_USER (required): Username for SMTP authentication.; SMTP_PASSWORD (required): Password or app-specific password for SMTP authentication.; SMTP_FROM (required): The only sender this server will use, e.g. "Name ". There is no from parameter.; SMTP_REPLY_TO: Reply-To header on every message, e.g. "Team ". Unset means no Reply-To header and replies go to SMTP_FROM. There is no reply_to parameter.; SMTP_ALLOW_SEND: Set to "true" to register the sending tools. Defaults to false: the server cannot send until it is set.; SMTP_ALLOWED_RECIPIENTS: Comma-separated addresses and @domains this server may write to. Required with SMTP_ALLOW_SEND=true; "" allows any.; SMTP_MAX_RECIPIENTS: Maximum distinct recipients across To, Cc and Bcc in one message. Default 10.; SMTP_MAX_SENDS_PER_HOUR: Sliding hourly cap on messages sent. Default 20.; SMTP_MAX_MESSAGE_BYTES: Maximum size of the composed message. Default 10485760.; SMTP_MAX_ATTACHMENT_BYTES: Maximum size of a single attachment. Default 5242880.; SMTP_ATTACHMENT_DIR: Directory attachments are read from. Unset means attachments are unavailable.; SMTP_ATTACHMENT_TYPES: Comma-separated content types that may be attached. Defaults to a document and image allowlist.; SMTP_SIGNATURE: Text appended below the standard signature delimiter of every message.; SMTP_AUDIT_LOG: File the audit lines are appended to, in addition to stderr.; SMTP_ALLOW_TOOLS: Comma-separated tool names, a prefix with one trailing , or "essential" for the curated preset.; SMTP_DENY_TOOLS: Comma-separated tool names or prefixes to remove, applied after SMTP_ALLOW_TOOLS.; SMTP_INSECURE_TLS: Set to "true" to accept self-signed certificates. Prefer a proper internal CA..

The published oci package is ghcr.io/ni-c/smtp-mcp:0.2.0. Its declared MCP transport is stdio.

Before connecting

Check the maintainer’s instructions for account access, authentication and the supported client configuration. Once connected, inspect the tools your client receives and try a small task that matches the server’s stated purpose. The registry description does not include a verified, complete tool list.

Project and source

View the publisher’s registry entry · Project repository · Project website. This profile uses version 0.2.0 from the registry. Registration identifies the publisher namespace; it does not establish that this is a first-party integration for every service it connects.

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