list_available_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 of behavioral disclosure. It states 'List' which implies a read-only operation, but does not explicitly mention permissions, side effects, rate limits, or pagination behavior. This is a significant gap for a tool with no annotation support.

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 well-structured with a concise one-line purpose, a clear parameter list, and a return type. The parameter descriptions are necessary given the schema's lack of detail. The return type is vague ('Dict[str, Any]: Response data') but does not add clutter. Overall, the structure is appropriate.

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?

The tool lacks annotations and an output schema, so the description must provide complete context. It fails to explain what 'available' means, whether filters can be combined, the structure of the response, or any prerequisites. It also does not differentiate from siblings, leaving the agent under-informed for a filterable list operation.

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 input schema is a single 'request' object with additionalProperties true, providing 0% parameter coverage. The description fully compensates by listing all parameters (page, page_size, filters) with types, defaults, and intended meanings. However, it does not explicitly clarify that these parameters should be nested inside the required 'request' object, creating slight ambiguity.

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 'List available phone numbers' with a specific verb and resource. However, it does not distinguish itself from the sibling tool 'list_phone_numbers', which could be interpreted as listing owned numbers. The phrase 'available' implies a different scope but no explicit contrast is made.

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?

There is no guidance on when to use this tool versus alternatives like 'list_phone_numbers' or other filtering tools. The description simply lists parameters without providing context about appropriate use cases or exclusions.

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