list_phone_numbers

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

With no annotations provided, the description carries full burden for behavioral disclosure. While it mentions pagination defaults and filtering capabilities, it doesn't describe authentication requirements, rate limits, error conditions, or what the response structure looks like beyond 'Dict[str, Any]'. For a listing tool with 1 required parameter and nested objects, this leaves significant behavioral gaps.

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 clear sections for Args and Returns. It's appropriately sized with no redundant information. However, the front-loaded purpose statement is overly brief and could benefit from more context before diving into parameters.

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 complexity (1 required parameter with nested objects, 0% schema coverage, no output schema, and no annotations), the description is incomplete. It documents filtering parameters that don't match the schema structure and provides minimal information about the response format. For a tool with schema/description mismatch, this creates significant uncertainty for an agent.

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 has 0% description coverage and shows only a single 'request' parameter of type object, while the description lists 6 specific filtering parameters. This creates a direct contradiction between schema and description. The description provides parameter semantics that don't align with the documented schema structure.

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 states the tool's purpose as 'List phone numbers', which is a clear verb+resource combination. However, it doesn't distinguish this tool from its sibling 'list_available_phone_numbers' or other listing tools in the server, leaving ambiguity about what specific type of phone numbers are being listed (owned vs available).

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 no guidance on when to use this tool versus alternatives like 'list_available_phone_numbers' or 'get_phone_number'. There's no mention of prerequisites, context for filtering, or comparison with sibling tools, leaving the agent to guess based on tool names alone.

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