wa_get_phone_numbers

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

With no annotations, the description carries the behavioral disclosure burden. It correctly implies a read-only listing operation ('List') and adds useful context about returned fields (quality_rating, status) and their diagnostic value. It does not mention permissions or pagination, but for a read-only list tool this is adequate.

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 concise and well-structured: a one-sentence summary, a usage paragraph explaining the connection to wa_send_template, and a final note on additional fields. No wasted words; each sentence contributes meaning.

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 no output schema, the description adequately explains the key return fields (display_phone_number, id, quality_rating, status) and their usage. It does not mention verified_name or potential pagination, but the tool is simple enough that this is not a major gap. Overall, it gives an agent enough context to invoke the tool and interpret results.

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% with both parameters (waba_id and fields) already described in the input schema. The description adds minimal parameter-specific detail beyond the schema, primarily clarifying the role of the return value 'id' as phone_number_id. This meets the baseline but does not exceed it.

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 tool lists phone numbers for a WABA, with a specific verb ('List') and resource. It also differentiates from siblings by linking to wa_send_template and explaining how to obtain phone_number_id.

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 explicitly says 'Use this to discover the phone_number_id required by wa_send_template', giving a clear when-to-use. It also mentions using quality_rating/status for diagnosing delivery problems. However, it does not explicitly name alternative tools for when not to use it, though sibling names like wa_get_business_accounts provide implicit context.

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