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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description adds that results carry pricing and onboarding terms, which is useful context, but says nothing about pagination, result volume, or how the limit behaves.

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 efficient sentence with the resource stated first and the return contents front-loaded. Nothing is wasted, though the brevity comes at the cost of the missing usage and parameter detail.

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?

With 6 undocumented parameters, no output schema, and only a one-line description, an agent cannot confidently construct a filtered query or know what a result looks like. The definition is adequate as a purpose statement but insufficient for correct invocation.

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 description coverage is 0% across 6 parameters, so the description carries the full burden. It gestures at capabilities and onboarding terms but never explains the filtering semantics of countries, number_types, available_only, or limit, leaving most parameters opaque.

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 gives a specific verb (list) and resource (available number offerings) and enumerates the returned data (setup/monthly prices, capabilities, onboarding terms), which distinguishes it from a plain inventory list like list_numbers. However, it never explicitly contrasts itself with siblings such as list_numbers or get_number_rules, leaving the boundary to inference.

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 indication of when to use this catalog versus list_numbers, get_number_rules, check_number_requirements, or request_number. No prerequisites, no exclusions, and no alternative named.

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