gsuite

google-gmail_send_message

Send email messages by providing a base64url encoded RFC 2822 formatted message.

Instructions

Send an email message. Requires message in RFC 2822 format encoded as base64url string

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": {
      "raw": "<raw>"
    },
    "name": "google-gmail_send_message"
  }
}

Input Schema

Name	Required	Description	Default
`raw`	Yes	RFC 2822 formatted and base64url encoded email message
`userId`	No	User's email address or 'me' for authenticated user

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.4.0Jul 13, 2026

TDQS

B3.3/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full burden. It only mentions the required format but does not disclose important behaviors such as whether the sending is immediate, potential failure modes, or rate limits. The description is too sparse for a send action.

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 sentence that efficiently conveys the core purpose and a key requirement. It is front-loaded and contains no extraneous information. However, it could be slightly more informative without losing conciseness.

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 the complexity of sending an email and the lack of an output schema, the description is incomplete. It does not mention success indicators, error conditions, or any constraints like attachment limits or size restrictions. A more comprehensive description is warranted.

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?

With 100% schema coverage, the schema already describes both parameters. The description adds no additional meaning beyond what is in the schema. Baseline score of 3 is appropriate.

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 tool's action: 'Send an email message.' It distinguishes from siblings like create_draft or modify_message, as sending is a distinct operation. The required format (RFC 2822 base64url) is specified, 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 usage for sending emails but does not provide explicit guidance on when to use this tool versus alternatives like google-gmail_create_draft or google-gmail_modify_message. No when-not-to-use or prerequisite information is given.

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