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

Annotations already declare it as a read-only, open-world lookup, and the description adds valuable behavioral details: pricing, payment mechanism, non-charging of failed calls, and behavior when no mapping exists. It does not cover rate limits or other operational constraints.

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 front-loaded with what the tool returns and efficiently covers source, failure behavior, and pricing. Every sentence carries useful information for an agent deciding whether and how to call it.

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 a one-parameter tool with an output schema and annotations, the description is largely complete: it explains inputs, source, no-result behavior, and payment model. A small gap remains around differentiation from similar ASN/BGP lookup siblings.

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 coverage is 100%, so the single IPv4 parameter is already well documented by the schema. The description reinforces that it accepts an IPv4 address but adds no new syntax or format constraints beyond what the schema provides.

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-resource pair: it maps an IPv4 address to ASN, BGP prefix, country, registry, and allocation date. It also names the underlying Team Cymru service. However, it does not explicitly distinguish itself from sibling tools such as security_bgp_prefix_origin or security_ip_geolocation_asn.

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?

The description states what the tool does but gives no explicit guidance on when to use it versus sibling ASN/BGP tools. The note about returning no origin when Cymru has no mapping is failure behavior, not usage selection guidance.

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