Google Workspace MCP Server

Instructions

Implementation Reference

• src/index.ts:450-502 (handler)

  The handler function that parses arguments, constructs a raw base64url-encoded email message with headers and body, and sends it using the Gmail API.

  private async handleSendEmail(args: any) {
    try {
      const { to, subject, body, cc, bcc } = args;
  
      const headers = [
        'Content-Type: text/plain; charset="UTF-8"',
        "MIME-Version: 1.0",
        `To: ${to}`,
        cc ? `Cc: ${cc}` : null,
        bcc ? `Bcc: ${bcc}` : null,
        `Subject: ${subject}`,
      ]
        .filter(Boolean)
        .join("\r\n");
  
      // Ensure proper separation between headers and body
      const email = `${headers}\r\n\r\n${body}`;
  
      // Encode in base64url
      const encodedMessage = Buffer.from(email)
        .toString("base64")
        .replace(/\+/g, "-")
        .replace(/\//g, "_")
        .replace(/=+$/, "");
  
      // Send the email
      const response = await this.gmail.users.messages.send({
        userId: "me",
        requestBody: {
          raw: encodedMessage,
        },
      });
  
      return {
        content: [
          {
            type: "text",
            text: `Email sent successfully. Message ID: ${response.data.id}`,
          },
        ],
      };
    } catch (error: any) {
      return {
        content: [
          {
            type: "text",
            text: `Error sending email: ${error.message}`,
          },
        ],
        isError: true,
      };
    }
  }

• src/index.ts:106-135 (schema)

  The input schema and metadata for the send_email tool, specifying required parameters to, subject, body and optional cc, bcc.

  {
    name: "send_email",
    description: "Send a new email",
    inputSchema: {
      type: "object",
      properties: {
        to: {
          type: "string",
          description: "Recipient email address",
        },
        subject: {
          type: "string",
          description: "Email subject",
        },
        body: {
          type: "string",
          description: "Email body (can include HTML)",
        },
        cc: {
          type: "string",
          description: "CC recipients (comma-separated)",
        },
        bcc: {
          type: "string",
          description: "BCC recipients (comma-separated)",
        },
      },
      required: ["to", "subject", "body"],
    },
  },

• src/index.ts:278-279 (registration)

  Registration in the CallToolRequestHandler switch statement, dispatching send_email calls to the handleSendEmail method.

  case "send_email":
    return await this.handleSendEmail(request.params.arguments);