list_numbers

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only says 'list of numbers' and does not state whether the operation is read-only, whether authentication is required, what the response format looks like, or whether pagination exists. For a tool with zero annotations and no output schema, this is insufficient. The description does not contradict any annotation, but it adds minimal insight beyond the action itself.

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 a single concise phrase, which is appropriately sized for a no-parameter tool. It is front-loaded with the core purpose. However, it could benefit from a brief mention of the output or usage context, but for its simplicity, it is well-structured and free of 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 lack of an output schema and annotations, the description should at least indicate what the tool returns (e.g., an array of phone number strings) and whether it has any side effects. The current description only states the subject matter. For an agent to correctly invoke and interpret the tool, more detail is needed, such as whether the list includes all numbers or only active ones. The minimal description makes the tool usable but not fully contextual.

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 tool has zero parameters, so the schema fully covers parameter semantics (vacuously). The baseline for 0 parameters is 4, and the description does not need to explain parameters. No additional semantic information is required because there is nothing to configure.

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 'Список номеров телефонов на аккаунте' (List of phone numbers on the account) clearly indicates a read-only listing operation targeting phone numbers. It uses a specific resource (phone numbers) and implies a list action. It is distinct from sibling tools like buy_number and send_sms, which have different purposes. It lacks an explicit verb like 'returns', but the intent is unambiguous.

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. The description does not mention prerequisites, such as requiring an existing account, nor does it contrast with siblings like buy_number or get_call_recording. No exclusions or conditions are provided, leaving the agent to infer that this is the default way to fetch numbers. This is a notable gap given the presence of sibling tools.

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