list_available_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 of behavioral disclosure. It conveys a read-only listing operation through the word 'List', but omits expected return shape, pagination or result limits, pricing/availability details, and authentication requirements.

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 concise sentences state the purpose first and then enumerate the filters. There is no filler or duplication; every word contributes operational value.

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?

For a low-complexity list endpoint with all parameters documented and no required arguments, the description provides enough to invoke it correctly, including default country and available filters. It does not describe the output payload, but the simple 'list' semantics and full schema coverage make the call largely self-contained.

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 the schema already documents all four parameters. The description adds the helpful framing that these are filters and mentions the AU default, but it does not clarify ambiguous values like number_type, keeping it at the schema-covered baseline.

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 a specific action ('List') and resource ('available DIDs for purchase'), and it lists the filters that narrow the search. It does not explicitly distinguish this from siblings like list_dids, though 'available for purchase' strongly implies the scope.

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 purpose phrase implicitly signals use when searching for purchasable numbers, and the filters give operational context. However, there is no explicit guidance about when to choose this tool over alternatives such as list_dids or purchase_did, so usage must be inferred.

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