# The Complete Directory of Email MCP Tools and Schemas (2026 Reference Guide)

_By Tayyab Mughal, Founder & AI Chief · 25 August 2026 · 2 min read_

> A comprehensive reference guide and JSON schema directory for email Model Context Protocol tools, including send_email, verify_domain, get_logs, and inspect_allowlist.

Looking for standard MCP schemas for email tools? Here is the complete production directory of tool definitions, input arguments, return types, and error codes.

## Standardized Email Tool Directory

To ensure interoperability across Claude, Cursor, ChatGPT, and custom LangGraph swarms, the email tooling ecosystem has converged on four core tool primitives.

| Tool Name | Purpose | Key Parameters | Return Type |
| --- | --- | --- | --- |
| send_email | Dispatches transactional message with allowlist check | to, subject, text, html, replyTo | { id, status, deliveredAt } |
| verify_domain_dns | Inspects SPF, DKIM, and DMARC status | domain | { spf: boolean, dkim: boolean, dmarc: string } |
| get_message_status | Checks delivery and bounce events | messageId | { id, event: "delivered" | "bounced", latencyMs } |
| inspect_allowlist | Returns authorized recipient domains for current key | none | { allowedDomains: string[], approvalMode: boolean } |

## JSON Schema Definitions for send_email

Standard schema used by @sadasend/mcp-server for outbound delivery.

```json
{
  "name": "send_email",
  "description": "Dispatches a transactional email to an authorized recipient.",
  "inputSchema": {
    "type": "object",
    "properties": {
      "to": {
        "type": "string",
        "format": "email",
        "description": "Destination email address."
      },
      "subject": {
        "type": "string",
        "minLength": 1,
        "description": "Clear subject line."
      },
      "text": {
        "type": "string",
        "description": "Plain-text email body."
      },
      "html": {
        "type": "string",
        "description": "Optional responsive HTML body."
      },
      "tags": {
        "type": "array",
        "items": { "type": "string" },
        "description": "Metadata tags for categorization."
      }
    },
    "required": ["to", "subject", "text"]
  }
}
```

## Standard Error Codes

- -32602 (Invalid Params): Recipient email address format is invalid.
- 403 (Forbidden Allowlist Refusal): The recipient domain is outside the authorized key scope.
- 429 (Rate Limit Exceeded): The agent has exceeded its hourly sending budget.

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_Tags: MCP, Reference, Schemas, DevTools_