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

No annotations are provided, so the description carries the full burden. It does declare 'Read-only' and lists the fields returned (handle, name, statuses, lifecycle events, raw record), which is useful. However it omits rate-limit behavior, auth requirements, and what happens when a domain has no RDAP server or is not found.

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?

One dense sentence, front-loaded with the action and resource, with the parenthetical gloss and the return-field list earning their place. No filler or redundancy.

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 single-parameter, read-only lookup with no output schema, the description covers purpose, mechanism and returned content adequately. It stops short of failure modes and TLD/RDAP-server coverage, which an agent would benefit from knowing.

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?

There is a single required parameter with 100% schema description coverage including a concrete example (example.com, 192.0.2.1). The description's 'domain or IP' phrasing aligns with but adds nothing beyond the schema, so the 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 a specific verb (look up) and resource (registration data) and clarifies the mechanism (RDAP, JSON successor to WHOIS), which cleanly separates it from siblings like dns_lookup, passive_dns or tls_certificate. It also enumerates what is returned (handle, name, statuses, lifecycle events, raw record), so an agent can identify it without opening the schema.

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?

Usage is implied rather than stated: it targets registration/ownership data, distinct from DNS resolution or reputation checks, but there is no explicit when-to-use guidance, no mention of alternatives such as passive_dns for historical ownership, and no note on lookup failures for unsupported TLDs.

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