Send WhatsApp Template Message

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

Beyond the annotations (which indicate readOnly=false), the description discloses that template messages must be pre-approved and that they bypass the 24-hour window rule. This adds useful behavioral context. There is no contradiction with the annotations, and while it does not mention side effects like delivery guarantees or idempotency, it provides meaningful additional info.

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 well-structured with a clear first sentence, followed by Args, Returns, and an Example. It is front-loaded with the core purpose. However, the Args section duplicates schema-provided parameter details, which adds redundancy. Overall it is reasonably concise and easy to scan.

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?

Since there is no output schema, the description appropriately defines return values as 'Message ID and delivery status'. It also includes a concrete example and the key business rule about the 24-hour window. The only notable gap is not mentioning the response_format parameter in the description, but the schema covers it, and the tool's complexity is moderate.

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 schema has 100% coverage with detailed descriptions for all five parameters. The description's Args section largely restates the schema (e.g., to, template_name) and adds no significant new meaning. It omits response_format entirely, but since the schema already fully documents it, the description does not need to compensate. The example provides a minor mapping hint, keeping this at the baseline.

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 opens with 'Send an approved template message', a specific verb and resource that clearly distinguishes this tool from the other whatsapp_send_* siblings (text, image, document, etc.). The added detail about the 24-hour window further clarifies its unique purpose, and the example demonstrates the expected mapping for template_name and language_code.

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 description states 'Templates are the only way to initiate conversations outside the 24-hour window', which gives a clear when-to-use context. It indirectly implies that for in-window conversations other send tools are appropriate, but it does not explicitly name alternatives or state when-not-to-use. This is clear context without explicit exclusions.

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