GMail Manager MCP

Instructions

Implementation Reference

• src/tools.ts:114-118 (handler)

  MCP tool handler for 'apply_label': validates input using Zod schema, calls GmailService.applyLabel, and returns formatted success response.

  case "apply_label": {
      const v = validated as z.infer<typeof schemas.apply_label>;
      await gmailService.applyLabel(v.messageId, v.labelId);
      return { content: [{ type: "text", text: `Label ${v.labelId} applied to email ${v.messageId}.` }] };
  }

• src/tools.ts:16-19 (schema)

  Zod input schema for the 'apply_label' tool defining messageId and labelId parameters with descriptions.

  apply_label: z.object({
      messageId: z.string().describe("Email message ID"),
      labelId: z.string().describe("Label ID to apply")
  }),

• src/tools.ts:50-55 (registration)

  Function exporting JSON schemas and descriptions for all MCP tools, including 'apply_label', for server registration.

  export const getToolDefinitions = () => 
      Object.entries(schemas).map(([name, schema]) => ({
          name,
          description: toolDescriptions[name],
          inputSchema: zodToJsonSchema(schema)
      }));

• src/gmail-service.ts:97-99 (helper)

  GmailService helper method implementing label application by calling Gmail API's messages.modify with addLabelIds.

  async applyLabel(messageId: string, labelId: string): Promise<void> {
      await this.modifyMessage(messageId, { addLabelIds: [labelId] });
  }

• src/gmail-service.ts:109-111 (helper)

  Private helper in GmailService that performs the actual Gmail API call to modify message labels.

  private async modifyMessage(id: string, requestBody: any): Promise<void> {
      await this.gmail.users.messages.modify({ userId: 'me', id, requestBody });
  }