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get_message

Retrieve a specific Gmail message by its ID with options to include or exclude HTML content for efficient email access and management.

Instructions

Get a specific message by ID with format options

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
idYesThe ID of the message to retrieve
includeBodyHtmlNoWhether to include the parsed HTML in the return for each body, excluded by default because they can be excessively large

Implementation Reference

  • Handler for 'get_message' tool: retrieves a specific Gmail message by ID using the Gmail API with full format, processes the payload to decode bodies and filter headers, and returns formatted response.
    async (params) => {
      return handleTool(config, async (gmail: gmail_v1.Gmail) => {
        const { data } = await gmail.users.messages.get({ userId: 'me', id: params.id, format: 'full' })
    
        if (data.payload) {
          data.payload = processMessagePart(data.payload, params.includeBodyHtml)
        }
    
        return formatResponse(data)
      })
    }
  • Input schema for 'get_message' tool: requires message ID, optional flag to include HTML bodies.
    {
      id: z.string().describe("The ID of the message to retrieve"),
      includeBodyHtml: z.boolean().optional().describe("Whether to include the parsed HTML in the return for each body, excluded by default because they can be excessively large")
    },
  • src/index.ts:561-578 (registration)
    Registration of the 'get_message' MCP tool on the server, including name, description, schema, and handler.
    server.tool("get_message",
      "Get a specific message by ID with format options",
      {
        id: z.string().describe("The ID of the message to retrieve"),
        includeBodyHtml: z.boolean().optional().describe("Whether to include the parsed HTML in the return for each body, excluded by default because they can be excessively large")
      },
      async (params) => {
        return handleTool(config, async (gmail: gmail_v1.Gmail) => {
          const { data } = await gmail.users.messages.get({ userId: 'me', id: params.id, format: 'full' })
    
          if (data.payload) {
            data.payload = processMessagePart(data.payload, params.includeBodyHtml)
          }
    
          return formatResponse(data)
        })
      }
    )
  • Helper function processMessagePart used in get_message handler to recursively decode message bodies (unless HTML excluded) and filter headers to a predefined list.
    const processMessagePart = (messagePart: MessagePart, includeBodyHtml = false): MessagePart => {
      if ((messagePart.mimeType !== 'text/html' || includeBodyHtml) && messagePart.body) {
        messagePart.body = decodedBody(messagePart.body)
      }
    
      if (messagePart.parts) {
        messagePart.parts = messagePart.parts.map(part => processMessagePart(part, includeBodyHtml))
      }
    
      if (messagePart.headers) {
        messagePart.headers = messagePart.headers.filter(header => RESPONSE_HEADERS_LIST.includes(header.name || ''))
      }
    
      return messagePart
    }
  • Shared helper handleTool wraps API calls with OAuth2 authentication, credential validation, and Gmail client creation for all tools including get_message.
    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}`
      }
    }

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observed

TDQS

A3.6/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the burden of transparency. It correctly indicates a read operation ('Get') but does not disclose other behavioral traits such as required permissions, error cases, or any side effects. Minimal but not misleading.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is very concise at 8 words, with no wasted text. It front-loads the key action. However, it could include slightly more structure or context (e.g., mentioning the optional parameter) without becoming verbose.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers the basic functionality but lacks information about return format, error handling, or result limits. Given the absence of an output schema and the presence of many sibling tools, a bit more detail would be beneficial, though it is minimally sufficient.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% and both parameters are documented in the schema. The description only adds the vague phrase 'format options' without elaborating which parameter that corresponds to (likely includeBodyHtml). The schema itself provides sufficient detail, so the description adds little extra meaning.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the verb 'Get' and the resource 'message', specifying 'by ID' and mentioning 'format options'. It distinguishes itself from list-oriented siblings like 'list_messages' and other get tools for different resources, making the purpose unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies use when you have a specific message ID but provides no explicit guidance on when to use this tool versus alternatives (e.g., list_messages, get_thread). No exclusions or comparative context are given.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.