Gmail MCP

Instructions

Implementation Reference

• src/index.ts:1178-1184 (handler)

  The handler function for the 'update_send_as' tool. It extracts the sendAsEmail from params, calls the shared handleTool helper to authenticate and execute the Gmail API update for the send-as alias.

  async (params) => {
    const { sendAsEmail, ...updateData } = params
    return handleTool(config, async (gmail: gmail_v1.Gmail) => {
      const { data } = await gmail.users.settings.sendAs.update({ userId: 'me', sendAsEmail, requestBody: updateData })
      return formatResponse(data)
    })
  }

• src/index.ts:1170-1177 (schema)

  Input schema using Zod for validating parameters of the update_send_as tool, including sendAsEmail (required) and optional fields like displayName, replyToAddress, etc.

  {
    sendAsEmail: z.string().describe("The send-as alias to be updated"),
    displayName: z.string().optional().describe("A name that appears in the 'From:' header"),
    replyToAddress: z.string().optional().describe("An optional email address that is included in a 'Reply-To:' header"),
    signature: z.string().optional().describe("An optional HTML signature"),
    isPrimary: z.boolean().optional().describe("Whether this address is the primary address"),
    treatAsAlias: z.boolean().optional().describe("Whether Gmail should treat this address as an alias")
  },

• src/index.ts:1168-1185 (registration)

  Registration of the 'update_send_as' tool on the MCP server using server.tool(), including name, description, input schema, and handler function.

  server.tool("update_send_as",
    "Updates a send-as alias",
    {
      sendAsEmail: z.string().describe("The send-as alias to be updated"),
      displayName: z.string().optional().describe("A name that appears in the 'From:' header"),
      replyToAddress: z.string().optional().describe("An optional email address that is included in a 'Reply-To:' header"),
      signature: z.string().optional().describe("An optional HTML signature"),
      isPrimary: z.boolean().optional().describe("Whether this address is the primary address"),
      treatAsAlias: z.boolean().optional().describe("Whether Gmail should treat this address as an alias")
    },
    async (params) => {
      const { sendAsEmail, ...updateData } = params
      return handleTool(config, async (gmail: gmail_v1.Gmail) => {
        const { data } = await gmail.users.settings.sendAs.update({ userId: 'me', sendAsEmail, requestBody: updateData })
        return formatResponse(data)
      })
    }
  )

• src/index.ts:49-65 (helper)

  Shared helper function used by update_send_as (and other tools) to handle OAuth2 authentication, credential validation, Gmail client creation, API execution, and error handling.

  const handleTool = async (queryConfig: Record<string, any> | undefined, apiCall: (gmail: gmail_v1.Gmail) => Promise<any>) => {
    try {
      const oauth2Client = queryConfig ? createOAuth2Client(queryConfig) : defaultOAuth2Client
      if (!oauth2Client) throw new Error('OAuth2 client could not be created, please check your credentials')
  
      const credentialsAreValid = await validateCredentials(oauth2Client)
      if (!credentialsAreValid) throw new Error('OAuth2 credentials are invalid, please re-authenticate')
  
      const gmailClient = queryConfig ? google.gmail({ version: 'v1', auth: oauth2Client }) : defaultGmailClient
      if (!gmailClient) throw new Error('Gmail client could not be created, please check your credentials')
  
      const result = await apiCall(gmailClient)
      return result
    } catch (error: any) {
      return `Tool execution failed: ${error.message}`
    }
  }