send_mail

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

With no annotations, the description must carry the behavioral burden, but it only adds the scope hint 'mail:send'. It does not disclose side effects, auth needs beyond the scope string, draft behavior, failure modes, or whether the email is actually delivered or just queued.

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 brief and front-loaded, with no wasted words. It is shorter than ideal for a 9-parameter mutation tool, but as a concise statement of the operation it is effective.

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 9 parameters, no annotations, no output schema, and no description of return behavior, this description is insufficient. An agent cannot determine whether to provide body_text or body_html, how attachments are referenced, what draft_id implies, or what happens on success/failure.

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?

The description adds no parameter meaning beyond what the schema already provides. The schema covers 6 of 9 parameters, so some semantics exist, but cc, bcc, and subject remain undescribed in both places. The description only reinforces the mailbox concept already present in mailbox_id.

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 action ('Send an email') and the resource ('from a mailbox'), making the core purpose unambiguous. It does not differentiate from sibling tools, but no sibling directly overlaps with sending, so the lack of differentiation is minor.

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 intended use is implied by the verb and resource, and this is the only sending-related tool in the sibling list. However, the description does not explain when to choose draft_id vs composing a new message, nor does it mention exclusions or prerequisites such as a valid mailbox or recipient format.

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