whatsapp_send

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

No annotations are provided, so the description carries the full burden. It explains address formats but does not disclose side effects, authentication requirements, or failure behavior. The send action is obvious, but no additional behavioral context is given.

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, focused sentence that front-loads the primary action and then clarifies the parameter format. No redundant or filler content.

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 2-parameter send tool, the description covers the most complex aspect (recipient format) and is sufficient for correct usage. It could mention message length limits or error behavior, but these are not critical for a basic text send operation.

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 descriptions are minimal, but the tool description adds significant clarity: it explains that 'to' accepts a raw phone number (digits, country code, no +) or JID, and provides explicit JID examples for individuals and groups. This goes beyond the schema and is essential for correct invocation.

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 'Send a WhatsApp text message' uses a specific verb and resource, clearly distinguishing it from the sibling tool whatsapp_send_image. It unambiguously states the tool's function.

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 text-message usage but does not explicitly state when to use this tool vs alternatives. It provides no exclusions or alternatives, so the agent must infer from the word 'text'.

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