whatsapp_send_contact

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

No annotations are provided, so the description must carry the full behavioral burden, but it fails to disclose any behavioral traits such as what happens if both displayName and vcard are provided, validation of vcard format, or the nature of the message delivery.

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 very short and front-loaded, conveying the core purpose in one sentence. While it could benefit from more structure, it is efficient and avoids unnecessary words.

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 8 parameters, no output schema, and no annotations, the description leaves major gaps. It does not explain the 'to' parameter format (JID), the behavior of optional parameters, or the return value, making it incomplete for safe usage.

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?

With only 38% schema coverage, the description adds minimal value by mentioning displayName and vcard as alternatives. It does not explain the format required for vcard, the meaning of other parameters like mentions or replyTo, or confirm if displayName or vcard is needed beyond the mutual exclusivity hint.

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 it sends a contact (vCard) message, which distinguishes it from other send_* tools like send_text or send_image. However, it does not explicitly differentiate from the similar-sounding 'whatsapp_create_contact' tool.

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?

It provides a usage hint to 'provide either displayName or vcard', implying mutual exclusivity, but lacks explicit guidance on when to use this tool versus alternatives like send_text or when not to use it.

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