Send Email

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

With no annotations, the description does carry real weight: it discloses the required API key environment variable and the Brevo-side constraint that the sender must be pre-verified. It omits the key behavioral fact for a mutation tool — that sending is an irreversible external side effect with no undo — and says nothing about rate limits or failure modes.

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?

A single front-loaded sentence with zero filler; the provider and the two prerequisites are packed into one clause.

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?

An output schema exists, so return values need no explanation. But for an 8-parameter outbound mutation with no annotations, the definition is thin — the 'one email' scope limit, irreversible delivery, and message-format expectations all go unstated.

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 only 13% (just dry_run), and the description elaborates on only one concept: that sender_email must correspond to a Brevo-verified sender. It says nothing about message format (plain text vs HTML), subject constraints, or reply_to/recipient_name handling across the remaining seven parameters.

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 ('Send one email') plus the delivery provider (Brevo), which implicitly separates it from send_whatsapp and preview_message. It stops short of naming any sibling explicitly, so disambiguation relies on the agent noticing the channel word.

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?

'Send one email' implies single-message, not bulk, and the parenthetical states the prerequisites (BREVO_API_KEY, verified sender). However, it never says when to prefer preview_message or the schema's dry_run flag before actually dispatching, and gives no exclusions.

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