list_available_phone_numbers

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

No annotations are provided, so the description must carry the full burden of behavioral disclosure. It only lists parameters and a usage hint, but does not mention that the operation is read-only, any rate limits, or what happens when no numbers are available. The description is minimal for a listing tool.

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 very concise, with the main purpose stated in the first sentence, followed by a workflow hint and a compact parameter list. Every sentence is necessary and there is no fluff.

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 low schema coverage and no annotations, the description is fairly complete for a simple listing tool. It explains parameters and usage context, and the existence of an output schema likely covers return structure. However, it could mention that the tool returns a list of available numbers with details.

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 0%, so the description must add meaning. It explains each parameter with defaults and options (e.g., type: TollFree or Local), which adds value beyond the schema's titles and defaults. However, it does not provide a complete list of allowable country codes or explain the implications of type selection.

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 that the tool lists available phone numbers for purchase, using the verb 'list' and resource 'available phone numbers'. It also hints at the workflow with provision_phone_number, but does not explicitly differentiate from the sibling tool 'list_phone_numbers' (which lists owned numbers).

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 provides clear guidance: 'Browse numbers before buying with provision_phone_number.' This implies a sequential workflow. However, it does not explicitly state when not to use this tool or mention alternative tools like list_phone_numbers.

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