WHOIS Lookup

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

Annotations already declare readOnlyHint=true, destructiveHint=false, etc. Description adds return structure details and rate limits, providing context beyond annotations. No contradiction. Moderate added value.

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?

Three concise sentences, each serving a purpose: purpose/data, usage/alternative, return/limits. Front-loaded and no wasted words.

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 tool with annotations covering safety and output schema hinted in description, all necessary context is provided: purpose, usage, rate limits, return fields. Complete.

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?

Only one parameter 'domain' with schema description covering 100%. Description does not add additional semantic details beyond what's in the input schema. 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?

The description starts with 'Retrieve WHOIS registration data: registrar, creation/expiry dates, nameservers, status.' This clearly states the action (retrieve) and resource (WHOIS data) with specific fields. It distinguishes from sibling 'domain_report' by noting 'for full audit use domain_report'.

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?

Explicitly states when to use: 'Use to verify domain ownership, age, expiration' and when not: 'for full audit use domain_report'. Also includes rate limits: 'Free: 30/hr, Pro: 500/hr', aiding in resource management.

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