Send Mail

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

With no annotations, the description carries the full burden of behavioral disclosure. It does state 'sends as the signed-in user' and 'requires delegated Mail.Send', but it does not warn that this sends a real, irreversible email or disclose side effects like saving to Sent Items (which is only in the schema). The action is a mutation with significant impact, yet the description omits 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 two concise sentences, front-loaded with the action and permission, and includes a helpful Chinese intent phrase for multilingual support. Every sentence earns its place with no redundancy.

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?

Despite a rich schema, the description lacks essential context for a mutation tool: no usage guidelines, no warning about irreversibility, and no mention of what the tool returns (since there is no output schema). It only covers the permission requirement, leaving the agent under-informed for selecting and invoking this tool.

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 schema already explains all parameters (subject, body, to, cc, bcc, bodyIsHtml, saveToSentItems). The description adds no parameter-level semantics beyond the schema, so the baseline score 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 clearly states 'Send an email as the signed-in user', which is a specific verb+resource. However, it does not explicitly distinguish itself from sibling tools like mail_send_draft or mail_reply, though the action of sending a fresh email is implied.

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?

No guidance is provided on when to use this tool versus alternatives such as mail_send_draft or mail_reply. It only mentions the permission requirement, which is a prerequisite rather than usage context. There is no when/when-not guidance.

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