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

Annotations already declare readOnlyHint, openWorldHint, and destructiveHint, so the safety profile is covered. The description adds behavioral context by disclosing the RDAP data source and the default behavior when 'ip' is omitted (caller's IP, country, city, ASN). It does not cover rate limits or error handling, but that is beyond the bar set by the annotations.

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 front-loads the purpose but includes redundancy: 'IP info.' repeats the opening, and 'Owner, network and country of an IP address' is restated as 'Who owns an IP address.' The sentences are short, but not every sentence earns its place.

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, read-only, one-parameter lookup with no output schema, the description is fairly complete: it names the data source, lists the returned fields, and explains the default when the parameter is omitted. It could mention limitations or rate limits, but it covers the essential context an agent needs to call it 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%, so the schema already defines 'ip' as IPv4/IPv6 with empty meaning the caller's own IP. The description adds only that omitting it returns the caller's IP, country, city, and ASN, which is mostly output information rather than additional parameter semantics. Baseline 3 is appropriate.

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?

States the resource (IP address) and the specific data returned (network name, range, CIDR, organization, country, registration date) via RDAP. This is clear enough to tell it apart from generic DNS or domain tools, though it does not name sibling tools explicitly. A 4 rather than 5 because sibling differentiation is implicit rather than stated.

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 explicit when-to-use guidance or alternatives are given. The description explains what the tool returns and the default when 'ip' is omitted, but it never says when to choose this over dns_lookup, domain_whois, or country_info. This is minimal guidance.

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