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

The annotation readOnlyHint: true already signals that this is a read-only operation, and the description's use of 'Query' is consistent. The description adds minimal extra behavioral context (e.g., what input types are accepted), but those are more purpose than behavior. No contradictions; it doesn't disclose rate limits, response format, or side effects beyond the annotation.

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 a single, front-loaded sentence that conveys the tool's purpose and input types with zero waste. No redundant information or fluff.

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 annotations declaring readOnlyHint=true measured, the description tells the agent what can be queried and implies a returned WHOIS/RDAP record. While it does not detail the response structure (no output schema exists), the simplicity of the tool and the known domain make this adequate. Slight deduction because it could mention that results vary by query type.

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?

The input schema provides 100% description coverage for the single 'query' parameter, fully defining its type and examples. The description adds the list of accepted query types (domain, IP, CIDR, ASN) which enhances understanding, but since the schema already covers the parameter, this is baseline credit.

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 clearly states a specific verb (Query) and resource (WHOIS/RDAP information) with explicit supported input types (domain, IP, CIDR, ASN). This distinguishes it from generic 'lookup' tools, but it does not explicitly differentiate from the sibling whois_batch_lookup, which would merit a 5.

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 guidance is given on when to use this tool versus the sibling whois_batch_lookup. The description only states what it does, leaving the agent to infer that this handles single queries while the batch tool handles multiple. No prerequisites, exclusions, or context are provided.

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