Send WhatsApp Image

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

Annotations already indicate readOnlyHint=false and idempotentHint=false, signaling a non-read-only, non-idempotent operation. The description adds that it returns a Message ID and delivery status, which is helpful for understanding the operation's outcome. However, it does not disclose other behavioral aspects like authentication requirements or rate limits, but these are not contradicted by annotations.

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 compact and well-structured, using an Args/Returns format. Every line provides necessary information without fluff. It is not as minimal as a single sentence, but it avoids redundancy and fits naturally within a standard docstring.

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's moderate complexity (4 parameters, no output schema), the description adequately explains the core action, parameter constraints, and return value. It lacks explicit error-handling or size-limit details, but for a straightforward send-image operation, it is sufficiently complete. The public URL requirement is a key contextual detail that is included.

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 the baseline is 3. The description's Args section reproduces parameter meanings already present in the schema (e.g., 'to', 'image_url', 'caption'), but does not add new semantics. It notably omits the 'response_format' parameter from its Args, although the schema covers it. No additional value is provided beyond the 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 'Send an image to a WhatsApp user via a public URL.' It uses a specific verb ('Send') and identifies the resource and medium, distinguishing it from sibling tools like whatsapp_send_text and whatsapp_send_document. The title and description align without ambiguity.

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 its use for sending images, but it does not explicitly state when to prefer this tool over alternatives or when not to use it. It does mention a key precondition: the image must be available via a public URL, which is a useful usage constraint, but there is no explicit comparison with sibling tools.

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