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

No annotations are provided, so the description carries the full disclosure burden. It mentions 'PRO' and a batching limit, but does not clarify authentication requirements, rate limits, whether the operation is read-only, or what happens with invalid or unlicensed NPNs.

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 very concise and front-loads the batching limit and examples. The unexplained 'PRO.' fragment is slightly cryptic, but the core operational sentence is efficient.

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?

Without annotations or an output schema, the definition should provide more context about return format and auth behavior. It does cover the core batch-check purpose and result fields, but leaves important operational details implicit.

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 schema documents access_token, while the description adds useful meaning for npns by stating these are NPNs and that up to 50 can be supplied. However, it still leaves the access_token requirement to the schema and does not add format or validation detail for the NPN array.

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 and resource: check NPNs, with batch scope up to 50 at once. It also indicates the returned information (licensed or not, product and company names), which helps distinguish it from a simple single-NPN lookup, though it does not explicitly name npn_check as the single-item alternative.

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?

It gives a clear usage context with the example of a marketplace or store catalogue and the 50-NPN limit. It does not explicitly state when to use npn_check or npn_detail instead, so it stops short of full alternative-routing guidance.

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