Send an email via the Gmail API to reply in-thread to support conversations, keeping message headers intact.
Send an email via the Gmail API.
| Name | Required | Description | Default |
|---|---|---|---|
| body | Yes | The email message data. | |
| userId | No | The user's email address. The special value 'me' can be used to indicate the authenticated user. | me |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false and openWorldHint=true, so the safety profile is partially covered. The description adds no behavioral traits beyond that, such as immediate sending, authentication requirements, irreversibility, or threading behavior; it essentially restates 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.
Is the description appropriately sized, front-loaded, and free of redundancy?
It is a single, front-loaded sentence with no wasted words. While it is sparse, the structure is efficient and the core action is stated first.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a mutation tool with open-world annotations and no output schema, the description is incomplete. It does not clarify that the message is sent immediately rather than saved as a draft, nor does it describe return behavior or error handling, leaving important context gaps.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, and the nested EmailContent fields are fully documented. The description adds no parameter-level meaning beyond the schema, so the baseline of 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a specific verb (Send) and resource (email via Gmail API), which is clearer than a generic action. However, it does not differentiate from sibling tools like gmail_drafts_create or slack_chat_post_message, so it misses the top mark.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description offers no guidance on when to use this tool versus alternatives, no prerequisites, and no exclusions. It simply states the action without any contextual routing.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.