Gmail MCP Server

by nk900600

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Hybrid

get_smime_info

Retrieve S/MIME encryption configuration details for a specific email alias to verify secure message settings.

Instructions

Gets the specified S/MIME config for the specified send-as alias

Input Schema

TableJSON Schema

Name	Required	Description	Default
`sendAsEmail`	Yes	The email address that appears in the 'From:' header
`id`	Yes	The immutable ID for the S/MIME config

Implementation Reference

src/index.ts:1239-1245 (handler)
Handler function for the 'get_smime_info' tool. It uses the shared handleTool wrapper to authenticate and call the Gmail API method gmail.users.settings.sendAs.smimeInfo.get to retrieve the S/MIME configuration for the specified sendAsEmail and id.
```
  async (params) => {
    return handleTool(config, async (gmail: gmail_v1.Gmail) => {
      const { data } = await gmail.users.settings.sendAs.smimeInfo.get({ userId: 'me', sendAsEmail: params.sendAsEmail, id: params.id })
      return formatResponse(data)
    })
  }
)
```

src/index.ts:1235-1238 (schema)

Zod input schema validation for the 'get_smime_info' tool, requiring 'sendAsEmail' (string) and 'id' (string).

{
  sendAsEmail: z.string().describe("The email address that appears in the 'From:' header"),
  id: z.string().describe("The immutable ID for the S/MIME config")
},

src/index.ts:1233-1245 (registration)

MCP server tool registration for 'get_smime_info', including name, description, input schema, and handler function.

server.tool("get_smime_info",
  "Gets the specified S/MIME config for the specified send-as alias",
  {
    sendAsEmail: z.string().describe("The email address that appears in the 'From:' header"),
    id: z.string().describe("The immutable ID for the S/MIME config")
  },
  async (params) => {
    return handleTool(config, async (gmail: gmail_v1.Gmail) => {
      const { data } = await gmail.users.settings.sendAs.smimeInfo.get({ userId: 'me', sendAsEmail: params.sendAsEmail, id: params.id })
      return formatResponse(data)
    })
  }
)

src/index.ts:50-66 (helper)

Shared helper function 'handleTool' used by get_smime_info and other tools for OAuth2 authentication, credential validation, Gmail client creation, and API call execution.

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}`
  }
}

src/index.ts:48-48 (helper)
Shared helper 'formatResponse' used to format API responses into MCP content format (JSON stringified).
```
const formatResponse = (response: any) => ({ content: [{ type: "text", text: JSON.stringify(response) }] })
```

Schema Changelog

Changes observed during successful MCP inspections.

First observedDec 8, 2025

TDQS

B3.1/5.0

Behavior2/5

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

Absent annotations (readOnlyHint, destructiveHint), the description merely says 'Gets', implying a read operation, but does not disclose behavioral traits like what happens if the config does not exist, authorization requirements, or side effects. The agent is left to infer behavior from the tool name.

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 a single concise sentence, but it is slightly vague ('the specified S/MIME config') and could be more front-loaded with the key action and resource. Still, it is efficient and avoids unnecessary words.

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

Completeness2/5

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

With no output schema and no annotations, the description is insufficiently complete. It fails to mention the return format, error handling, or how the S/MIME config is scoped to the send-as alias. Given the tool's simplicity, more detail would aid reliable invocation.

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% with both parameters described. The description adds no meaning beyond the schema; it does not clarify the relationship between sendAsEmail and id or specify format constraints. Baseline 3 is appropriate since schema covers the parameters.

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 it 'Gets the specified S/MIME config for the specified send-as alias', identifying the specific verb (gets), resource (S/MIME config), and scope (by send-as alias). It effectively distinguishes from siblings like insert_smime_info, delete_smime_info, and list_smime_info.

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

Usage Guidelines2/5

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

No guidance is provided on when to use this tool versus alternatives, such as list_smime_info for retrieving all configs or insert_smime_info for creating new ones. There are no prerequisites, exclusions, or context for conditional use.

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

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