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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description's '[read]' tag merely restates readOnlyHint and adds no new behavioral context, but it does not contradict anything.

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 compact sentence with the key semantics front-loaded. The phrasing 'Numbers no assistant calls' is slightly awkward but wastes no space.

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?

For a simple filtered-list tool with rich annotations and no output schema, the semantic definition of the list is adequate. However, pagination behavior and the relation to sibling opt-out tools are left unaddressed.

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?

Both parameters (page, per_page) have 0% schema description coverage, and the description says nothing about pagination or defaults. It does not compensate for the schema gap.

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 identifies the resource concretely: a list of numbers the assistant must not call, i.e. a do-not-call list. That is meaningfully more specific than the name alone, though it never distinguishes this from list_sms_optouts or add_voip_optouts.

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 indication of when to consult this list versus list_voip_numbers or list_sms_optouts, and no prerequisites such as whether it must be checked before place_voip_call. Usage is only implied by the tool name.

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