wa_list_phone_numbers

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 signals a read-only operation via the verb 'List' but does not disclose return format, pagination, rate limits, or any side effects. For a tool with no output schema, this is a significant gap.

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, front-loaded sentence with no redundant words. It efficiently communicates the core action and resource, making it easy to parse.

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 simplicity of the tool (one parameter, no output schema), the description is too minimal. It omits what the response contains, whether listing is paginated, or any constraints. Without an output schema, the agent has no expectations for the return value.

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 has a single required parameter waba_id with no description (0% coverage). The tool description mentions 'WhatsApp Business Account', providing context that waba_id is the account identifier, but it does not explicitly define the parameter or explain how to obtain the ID. Partial compensation.

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 action (List), the resource (phone numbers), and the scope (attached to a WhatsApp Business Account). This distinguishes it from siblings like wa_get_phone_number (retrieves a single number) and wa_list_business_accounts (lists accounts).

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 when to use the tool: when you need to list phone numbers for a given WhatsApp Business Account. However, it does not explicitly mention alternatives or prerequisites, such as first using wa_list_business_accounts to obtain the waba_id, so it lacks full exclusion guidance.

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