Enviar correo

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

Annotations only cover readOnlyHint=false and openWorldHint=true, so the description carries the interesting detail: a configuration-gated failure mode (MAIL_ALLOW_SEND) and the side effect of writing a copy to Sent. The explicit-request constraint is valuable behavioral context. It stops short of full disclosure (no rate limits, attachment handling, or return/failure detail beyond the one flag).

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?

Two tightly written sentences, zero filler, with the operational constraint and the consent gate front-loaded where an agent will see them 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 no output schema, the description covers the critical behavioral facts (failure gate, Sent-copy side effect, consent requirement), which is genuinely useful. But it leaves the nine-parameter surface entirely undocumented beyond the schema's terse field names, so an agent lacks guidance on composing a valid call.

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?

Nine parameters with only 11% schema description coverage, and the description adds nothing about any of them — no mention of to/cc/bcc semantics, html vs text precedence, references/in_reply_to threading, or the 5-attachment cap. With coverage this low, the description was obligated to compensate and does not.

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?

States a specific verb and resource ('Envía un correo por SMTP') plus two concrete behaviors: SMTP transport and saving a copy to Sent. That distinguishes it from siblings like create_draft or reply_message, though those alternatives are never named, so the differentiation is inferred rather than explicit.

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?

Gives a hard precondition gate ('Falla si MAIL_ALLOW_SEND no es true') and an explicit usage restriction ('No lo uses sin un pedido explícito de la persona en este turno'). Strong when-to-use guidance, but it never routes to the sibling that should be used instead (create_draft, reply_message).

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