Send WhatsApp Text Message

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

Annotations already indicate this is a write operation (readOnlyHint=false). The description adds meaningful context by stating the return value ('Message ID and delivery status') and documenting parameters like preview_url. It does not cover error conditions or delivery semantics, but the annotation coverage reduces the burden.

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 clear sections (Args, Returns, Examples) and begins with a one-sentence purpose. It is slightly repetitive with the schema but remains concise and readable without excessive verbosity.

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 simple send-text tool with four scalar parameters and no output schema, the description provides the essential details: parameters, max length, return info, and an example. It lacks guidance on delivery status values or alternative tools, but the overall context is adequate for an agent to invoke it correctly.

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 100%, so all parameters are already documented. The description repeats these details and adds an example but does not clarify response_format, which is only in the schema. It adds marginal value beyond the structured schema.

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 tool's purpose: 'Send a text message to a WhatsApp user.' This is a specific verb+resource combination that distinguishes it from sibling tools like whatsapp_send_image or whatsapp_send_template. The example further reinforces the core use case.

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 implies usage through the title and summary but does not explicitly contrast with alternatives such as whatsapp_send_template or when to use image/document sends. The example gives a basic invocation pattern but no guidance on when this tool is preferred or deprecated.

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