Send Gmail Message

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

Annotations indicate the tool is mutable (readOnlyHint=false) and not destructive (destructiveHint=false). The description adds the behavioral detail of 'elicitation support for untrusted recipients,' suggesting user prompting, but it does not explain the mechanism, auth requirements, or any rate limits. Beyond the annotation-provided info, the description adds limited behavioral context.

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?

The description is extremely concise—12 words in a single sentence. It is front-loaded with the primary action ('Send an email') and contains no superfluous information. Every word serves a purpose, though the brevity comes at the cost of completeness.

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?

Given the complexity of the tool (9 parameters, multiple content types, MJML support, and interaction with untrusted recipients), the description is far too brief. It lacks essential context about when to use email_spec, how content_type interacts with body/html_body, and what 'elicitation support' entails. The presence of an output schema partially mitigates return value concerns, but the tool's usage context is insufficiently covered.

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?

With 100% schema description coverage, the schema already documents all parameters thoroughly. The description does not add new meaning beyond stating the tool has 'elicitation support for untrusted recipients,' which is about the tool behavior, not parameter specifics. Baseline score of 3 is appropriate as the description does not degrade or enhance parameter understanding.

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 clearly states the tool sends an email using Gmail, and the mention of 'elicitation support for untrusted recipients' helps distinguish it from sibling tools like draft_gmail_message. The verb 'send' and resource 'email' are specific and unambiguous.

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 does not explicitly state when to use this tool versus alternatives such as draft_gmail_message or reply_to_gmail_message. There is no guidance on prerequisites (e.g., must have a draft) or when to avoid using it. The mention of 'untrusted recipients' implies a context but no clear when-to-use or when-not-to-use.

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