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

The annotation already declares readOnlyHint and openWorldHint, so the read-only nature is covered. The description adds meaningful behavioral context by stating that the tool 'flag[s] exposed personal identity fields' and lists the specific fields (registrant name, email, phone, address), which goes beyond a simple lookup and is not captured in annotations. However, it does not describe the output format, which is a minor gap.

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 two sentences, immediately states the main action, and contains no filler. It is front-loaded with the core purpose and the 'Read-only RDAP lookup' note reinforces safety without being verbose.

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?

With no output schema, the description should clarify what the tool returns; it only says it 'flags' fields without specifying the response structure (e.g., list, boolean, details). The tool is relatively simple, and annotations cover safety, but the missing return-value information prevents a higher score.

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 100% with a single parameter 'domain' that includes an example. The description does not add additional semantics beyond the schema, so the baseline of 3 is appropriate; it does not need to compensate for any coverage gap.

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 uses specific verbs ('look up', 'flag') and clearly identifies the resource (domain's public WHOIS/RDAP registration record). It distinguishes itself from sibling tools like dp_check_domain_breaches or dp_check_email_security by focusing on personal identity field exposure, making its purpose unambiguous.

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 clearly implies the use case: checking a domain's registration privacy and exposed identity fields. However, it does not explicitly mention alternatives or when not to use this tool. The context is clear enough for an agent to decide when to invoke it, though a direct contrast with sibling tools would strengthen it.

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