whatsapp_send_template

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

With no annotations provided, the description carries the full burden. It discloses that sending a template message is a write operation and adds the behavioral constraint about timing. However, it does not mention error cases (e.g., template not approved), rate limits, or authentication details beyond the required parameters.

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 a single sentence of 16 words, front-loading the purpose and the critical condition. Every word is essential, and there is no redundant information.

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 the tool has 6 parameters and no output schema or annotations, the description adequately explains the core use case and when to invoke it. However, it lacks details on return values, error handling, and where to find template names, which would be needed for full autonomous invocation.

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 input schema has 6 parameters with only 33% description coverage. The description adds no parameter-specific information beyond what is in the schema. For example, it does not explain 'bearer_token', 'phone_number_id', 'to', 'template_name', or 'components'. This low coverage combined with no added parameter meaning results in a score of 2.

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), the resource (WhatsApp template message), and crucially adds the condition 'required for first contact or >24h since last message', which distinguishes it from other WhatsApp sending tools like whatsapp_send_text.

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 explicitly specifies when this tool is required (first contact or >24h since last message), providing clear context for the agent to decide when to use it over alternatives. It does not list exclusions or alternatives explicitly, but the condition implicitly covers when not to use other tools.

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