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

Annotations already declare readOnlyHint, openWorldHint, and destructiveHint=false, so the safety profile is covered. The description adds a useful disclosure that registrant contact fields are omitted, but it does not mention behavior for unregistered domains, TLD/registry coverage gaps, or rate limiting from upstream RDAP servers.

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?

Two short sentences, front-loaded with the operation and followed by the key output caveat. No wasted text; the only weakness is that it ends without any usage/routing sentence.

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?

There is no output schema, so the description bears some burden of explaining what is returned. It discloses one important exclusion (registrant contacts) but does not describe what the summary actually contains (status, events, nameservers, registrar), leaving the agent to guess at the result shape.

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 description coverage is 0%, so the single 'domain' parameter is documented nowhere beyond its type and length bounds. The description does not clarify accepted format (bare domain vs URL, IDN/punycode handling, subdomain behavior), which it should compensate for given the low coverage.

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 and resource ('Return the public RDAP registration summary for a domain'), which clearly identifies the operation. It implicitly separates itself from sibling checks like check_domain_delegation or check_dnssec by naming RDAP registration data, but it does not explicitly distinguish itself from those siblings.

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?

There is no when-to-use guidance and no named alternative. The agent must infer from the RDAP phrasing whether this differs from check_domain_delegation or lookup_ip_info, and nothing states when this tool is the wrong choice.

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