list_verified_caller_ids

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 does not mention response format, pagination, ordering, what 'verified' entails, or any limits. For a listing operation with no output schema and no annotations, this is a notable gap in what the agent can expect back.

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?

A single, front-loaded sentence with zero filler words. It is appropriately sized for a parameterless tool, though it is arguably slightly under-specified given the absence of any behavioral or return-value context.

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 tool's low complexity (no params, no annotations), the description is mostly adequate: it names the resource and scope. However, with no output schema, the return format is entirely unspecified, and the meaning of 'verified' is not explained, leaving moderate gaps for a tool an agent would call blind.

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 there is nothing for the description to clarify. Per the baseline rule for 0-param tools, a 4 is appropriate; the empty schema already confirms no arguments are needed.

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 a specific verb ('List'), a specific resource ('verified caller IDs'), clarifies the acronym (CLI), and scopes it to 'the account.' No sibling tool lists caller IDs, so it is cleanly distinguished from the other list/create/update/delete tools in the set. The parenthetical clarification adds precision.

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?

No explicit when-to-use or when-not-to-use guidance, and no alternative tools are named. However, as a parameterless read-only listing operation, its intended usage is strongly implied by the name and description. It falls into the 'implied usage' category rather than providing explicit exclusions or comparisons.

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