Gmail MCP Server

gmail_send_message

Sends an email via Gmail using recipient, subject, body, and optional CC/BCC fields.

Instructions

Send a Gmail message.

Args: to: Recipient email address subject: Email subject body: Email body content cc: CC recipients (comma-separated) bcc: BCC recipients (comma-separated)

Returns: Dictionary with send result

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "to": "<to>",
      "subject": "<subject>",
      "body": "<body>"
    },
    "name": "gmail_send_message"
  }
}

Input Schema

Name	Required	Description	Default
`cc`	No
`to`	Yes
`bcc`	No
`body`	Yes
`subject`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jul 30, 2026

TDQS

B3/5.0

Behavior2/5

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

No annotations provided; the description does not disclose behavioral traits such as rate limits, size limits, asynchronous behavior, or error handling. For a mutation tool, this is a significant gap.

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 concise with a clear structure: one-liner verb, then args list, then return value. The first sentence is informative. No wasted words, though the 'Returns' line is vague.

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?

Given 5 parameters, no output schema, and no annotations, the description should provide more context about the return dictionary, error handling, and usage scenarios. The sibling tool with attachment is mentioned but not differentiated. The description feels like a basic doc rather than comprehensive guidance.

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

Parameters4/5

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

The description adds meaning beyond the schema by describing each parameter (to, subject, body, cc, bcc) and noting that cc/bcc are comma-separated. With 0% schema description coverage, this is valuable, though it doesn't specify format for 'to' (single email vs multiple) or body content type.

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

Purpose4/5

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

The description clearly states 'Send a Gmail message' with a clear verb+resource. It distinguishes from sibling tools like gmail_send_message_with_attachment by omission, implying it sends without attachments. However, it could be more specific about supported body formats (plain text vs HTML).

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 on when to use this tool vs alternatives (e.g., gmail_send_message_with_attachment). No prerequisites (e.g., authentication, sending limits) are mentioned. The description only lists parameters without context.

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

Deploy Server