WHOIS lookup

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

Annotations already cover read-only, idempotent, non-destructive behavior. The description adds value by disclosing that it uses RDAP or WHOIS depending on registry support, and that data may be limited to public information ('where public'). This contextualizes the tool's behavior beyond 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 is two sentences, front-loaded with the data scope and fields, followed by the protocol note. Every word earns its place; there is no redundancy 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 tool with no output schema, the description covers what the tool does, what data it returns, and the protocol nuance. It sufficiently equips an agent to decide when to invoke it and what to expect.

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 already fully documents the query parameter with format examples (domain, IP, CIDR, AS number). The description repeats these same resource types without adding new semantic detail, so it provides borderline marginal value over the schema. Baseline 3 is appropriate given 100% schema 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?

The description clearly identifies the tool as returning registration data for domains, IPs, networks, or AS numbers, with specific data fields (registrar, dates, name servers, holder, contacts). This is distinct from sibling tools like DNS lookup or subdomain search, so an agent can easily differentiate it.

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 implies when to use the tool (when registration data is needed for the listed resource types) but does not explicitly mention alternatives or exclusions. It provides clear context for the tool's purpose, though it stops short of naming sibling tools to avoid.

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