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

With no annotations, the description carries the full behavioral burden well: it names the two data sources, describes the data retrieved, states key limitations, says it is designed for one-at-a-time lookups, and discloses the $0.005 x402/USDC payment requirement. It does not describe error behavior or response freshness, which keeps it from a 5.

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 the usage condition, then follows with sources, exclusions, batching behavior, and cost. Every sentence contributes specific information, and the length is appropriate for a paid lookup tool.

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?

Although there is no output schema or annotations, the description names the key returned data elements: holder, country, date, abuse contact, and origin ASN. It also covers the payment model and limitations, leaving an agent with enough context to call and interpret the tool correctly.

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%, and the single parameter is already documented as an IPv4 or IPv6 address. The description adds only the framing of one address per call, which is useful but not substantially beyond the schema.

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 target: looking up one IPv4/IPv6 address for ownership intelligence via RDAP and ASN data. It clearly scopes the tool against adjacent capabilities by excluding city-level geolocation and VPN/proxy detection, so an agent can distinguish it from related red_* and evm_* tools.

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 an explicit use case: deciding whether to block or trust an IP. It also states what the tool deliberately does not cover, but it does not name sibling alternatives such as red_asn or red_whois for cases where those would be more appropriate.

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