Enviar template de teste (envia de verdade)

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

Annotations only say it is not read-only / not idempotent / open-world. The description adds what the tool actually does in the world: it sends a real paid message, returns the wamid, and real delivery or failure (error codes 131037, 131042) surfaces only asynchronously in the status webhook. That is exactly the kind of consequence an agent cannot infer from the schema.

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 short paragraphs: the first front-loads the action and the cost/phase constraint, the second covers the confirmation gate and the async delivery caveat. No sentence is filler.

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?

There is no output schema, and the description compensates by stating the return value (wamid) and warning that delivery confirmation is not in the response. Combined with the confirmation gate and error-code routing, an agent has everything needed to call it safely.

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 coverage is 100%, so the baseline is 3; the description still adds the operational rule that confirm must be true and only after the user confirms, plus the recipient format and the hello_world / en_US defaults. The mention of phone_number_id falling back to the META_PHONE_NUMBER_ID env var lives in the schema rather than the description, so it stops short of a 5.

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 concrete verb and resource ('ENVIA uma mensagem real de template pelo número') and immediately flags the cost implication, which distinguishes it from every read-only sibling like wa_list_templates or wa_diagnose. No sibling sends messages, and the description makes that uniqueness 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 an explicit precondition chain: only in the 'primeiro-envio' phase, to one of your own contacts, and only after wa_diagnose returns without FAIL – naming the sibling tool that gates it. It also implies when-not by restricting scope to test sending rather than bulk messaging.

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