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MCP server that sends mail over SMTP, gated behind an allowlist and a human confirmation
SMTP is an MCP server entry in ChatHome Skills, sourced from Official MCP Registry and scored 73/100. As a Model Context Protocol server, it exposes tools that MCP-compatible LLM clients such as Claude, Cursor, and Copilot can call directly, extending an agent's reach beyond its built-in capabilities. ChatHome Skills discovered this entry through its daily ingest of official registries and GitHub discovery queries, and re-verifies repository facts, freshness signals, and install metadata on every run. The quality score weighs official-registry presence, a working install command, license clarity, GitHub star trajectory, and repository freshness — the full formula is on the Sources page. The install command above is ready to copy. Review the last-pushed date and repository status before adding SMTP to a production agent workflow; the snapshot facts below are point-in-time values from the most recent ingest.
npx -y @ni-c/smtp-mcp@0.2.0Review the upstream source before running this command.
{
"_meta": {
"io.modelcontextprotocol.registry/official": {
"status": "active",
"isLatest": true,
"updatedAt": "2026-09-07T18:06:20.626217Z",
"publishedAt": "2026-09-07T18:06:20.626217Z",
"statusChangedAt": "2026-09-07T18:06:20.626217Z"
}
},
"server": {
"name": "io.github.ni-c/smtp-mcp",
"title": "SMTP",
"$schema": "https://static.modelcontextprotocol.io/schemas/2025-12-11/server.schema.json",
"version": "0.2.0",
"packages": [
{
"version": "0.2.0",
"transport": {
"type": "stdio"
},
"identifier": "@ni-c/smtp-mcp",
"registryType": "npm",
"environmentVariables": [
{
"name": "SMTP_HOST",
"format": "string",
"isRequired": true,
"description": "Hostname of the SMTP server, e.g. smtp.example.net."
},
{
"name": "SMTP_PORT",
"format": "number",
"description": "Port. Defaults to 587 for starttls, 465 for implicit, 25 for none."
},
{
"name": "SMTP_TLS",
"format": "string",
"description": "starttls (default), implicit or none. STARTTLS is required, never opportunistic."
},
{
"name": "SMTP_USER",
"format": "string",
"isRequired": true,
"description": "Username for SMTP authentication."
},
{
"name": "SMTP_PASSWORD",
"format": "string",
"isSecret": true,
"isRequired": true,
"description": "Password or app-specific password for SMTP authentication."
},
{
"name": "SMTP_FROM",
"format": "string",
"isRequired": true,
"description": "The only sender this server will use, e.g. \"Name <person@example.net>\". There is no from parameter."
},
{
"name": "SMTP_REPLY_TO",
"format": "string",
"description": "Reply-To header on every message, e.g. \"Team <team@example.net>\". Unset means no Reply-To header and replies go to SMTP_FROM. There is no reply_to parameter."
},
{
"name": "SMTP_ALLOW_SEND",
"format": "boolean",
"description": "Set to \"true\" to register the sending tools. Defaults to false: the server cannot send until it is set."
},
{
"name": "SMTP_ALLOWED_RECIPIENTS",
"format": "string",
"description": "Comma-separated addresses and @domains this server may write to. Required with SMTP_ALLOW_SEND=true; \"*\" allows any."
},
{
"name": "SMTP_MAX_RECIPIENTS",
"format": "number",
"description": "Maximum distinct recipients across To, Cc and Bcc in one message. Default 10."
},
{
"name": "SMTP_MAX_SENDS_PER_HOUR",
"format": "number",
"description": "Sliding hourly cap on messages sent. Default 20."
},
{
"name": "SMTP_MAX_MESSAGE_BYTES",
"format": "number",
"description": "Maximum size of the composed message. Default 10485760."
},
{
"name": "SMTP_MAX_ATTACHMENT_BYTES",
"format": "number",
"description": "Maximum size of a single attachment. Default 5242880."
},
{
"name": "SMTP_ATTACHMENT_DIR",
"format": "string",
"description": "Directory attachments are read from. Unset means attachments are unavailable."
},
{
"name": "SMTP_ATTACHMENT_TYPES",
"format": "string",
"description": "Comma-separated content types that may be attached. Defaults to a document and image allowlist."
},
{
"name": "SMTP_SIGNATURE",
"format": "string",
"description": "Text appended below the standard signature delimiter of every message."
},
{
"name": "SMTP_AUDIT_LOG",
"format": "string",
"description": "File the audit lines are appended to, in addition to stderr."
},
{
"name": "SMTP_ALLOW_TOOLS",
"format": "string",
"description": "Comma-separated tool names, a prefix with one trailing *, or \"essential\" for the curated preset."
},
{
"name": "SMTP_DENY_TOOLS",
"format": "string",
"description": "Comma-separated tool names or prefixes to remove, applied after SMTP_ALLOW_TOOLS."
},
{
"name": "SMTP_INSECURE_TLS",
"format": "boolean",
"description": "Set to \"true\" to accept self-signed certificates. Prefer a proper internal CA."
}
]
},
{
"transport": {
"type": "stdio"
},
"identifier": "ghcr.io/ni-c/smtp-mcp:0.2.0",
"registryType": "oci",
"environmentVariables": [
{
"name": "SMTP_HOST",
"format": "string",
"isRequired": true,
"description": "Hostname of the SMTP server, e.g. smtp.example.net."
},
{
"name": "SMTP_PORT",
"format": "number",
"description": "Port. Defaults to 587 for starttls, 465 for implicit, 25 for none."
},
{
"name": "SMTP_TLS",
"format": "string",
"description": "starttls (default), implicit or none. STARTTLS is required, never opportunistic."
},
{
"name": "SMTP_USER",
"format": "string",
"isRequired": true,
"description": "Username for SMTP authentication."
},
{
"name": "SMTP_PASSWORD",
"format": "string",
"isSecret": true,
"isRequired": true,
"description": "Password or app-specific password for SMTP authentication."
},
{
"name": "SMTP_FROM",
"format": "string",
"isRequired": true,
"description": "The only sender this server will use, e.g. \"Name <person@example.net>\". There is no from parameter."
},
{
"name": "SMTP_REPLY_TO",
"format": "string",
"description": "Reply-To header on every message, e.g. \"Team <team@example.net>\". Unset means no Reply-To header and replies go to SMTP_FROM. There is no reply_to parameter."
},
{
"name": "SMTP_ALLOW_SEND",
"format": "boolean",
"description": "Set to \"true\" to register the sending tools. Defaults to false: the server cannot send until it is set."
},
{
"name": "SMTP_ALLOWED_RECIPIENTS",
"format": "string",
"description": "Comma-separated addresses and @domains this server may write to. Required with SMTP_ALLOW_SEND=true; \"*\" allows any."
},
{
"name": "SMTP_MAX_RECIPIENTS",
"format": "number",
"description": "Maximum distinct recipients across To, Cc and Bcc in one message. Default 10."
},
{
"name": "SMTP_MAX_SENDS_PER_HOUR",
"format": "number",
"description": "Sliding hourly cap on messages sent. Default 20."
},
{
"name": "SMTP_MAX_MESSAGE_BYTES",
"format": "number",
"description": "Maximum size of the composed message. Default 10485760."
},
{
"name": "SMTP_MAX_ATTACHMENT_BYTES",
"format": "number",
"description": "Maximum size of a single attachment. Default 5242880."
},
{
"name": "SMTP_ATTACHMENT_DIR",
"format": "string",
"description": "Directory attachments are read from. Unset means attachments are unavailable."
},
{
"name": "SMTP_ATTACHMENT_TYPES",
"format": "string",
"description": "Comma-separated content types that may be attached. Defaults to a document and image allowlist."
},
{
"name": "SMTP_SIGNATURE",
"format": "string",
"description": "Text appended below the standard signature delimiter of every message."
},
{
"name": "SMTP_AUDIT_LOG",
"format": "string",
"description": "File the audit lines are appended to, in addition to stderr."
},
{
"name": "SMTP_ALLOW_TOOLS",
"format": "string",
"description": "Comma-separated tool names, a prefix with one trailing *, or \"essential\" for the curated preset."
},
{
"name": "SMTP_DENY_TOOLS",
"format": "string",
"description": "Comma-separated tool names or prefixes to remove, applied after SMTP_ALLOW_TOOLS."
},
{
"name": "SMTP_INSECURE_TLS",
"format": "boolean",
"description": "Set to \"true\" to accept self-signed certificates. Prefer a proper internal CA."
}
]
}
],
"repository": {
"url": "https://github.com/ni-c/smtp-mcp",
"source": "github"
},
"websiteUrl": "https://smtp-mcp.ni-c.de",
"description": "MCP server that sends mail over SMTP, gated behind an allowlist and a human confirmation"
}
}