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

Annotations already flag non-read-only, non-idempotent, open-world behavior, and the description adds meaningful context beyond them: the message goes only to the owner's own verified number and never to recipients, so an agent knows this is a safe, non-broadcast send. It still omits whether a log entry is created or what happens if the owner's number is unverified.

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?

Two short sentences, front-loaded with the action and recipient scope, with the safety guarantee placed last. Nothing is redundant or padded.

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 only three parameters, no output schema, and annotations covering the safety profile, the definition gives an agent enough to invoke it confidently. The remaining gap is optionality/defaulting of sample_record and any note about needing the owner's phone verified first.

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 coverage is 100%, so all three parameters are already documented, including sample_record as 'Field values to render the message with.' The description's phrase 'rendered with a sample record' mirrors rather than extends the schema, and it does not clarify that sample_record is optional or what happens when it is omitted.

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?

States a specific verb ('Send'), a specific resource (a saved trigger's message), and the exact scope ('once to the owner's own verified WhatsApp number, from the trigger's sending number'). This clearly separates it from suggest_whatsapp_trigger_message (drafting) and list_whatsapp_trigger_logs (history) among the siblings.

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 word 'test' plus 'send once' implies this is a preview/verification step before enabling a trigger, and the schema points to list_whatsapp_triggers for the trigger_id. However, the description never explicitly says when to use this versus suggest_whatsapp_trigger_message or update_whatsapp_trigger, nor does it state prerequisites such as a verified owner phone.

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