whois_lookup

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

The description discloses that it queries real WHOIS servers directly via TCP port 43 without requiring an API key. This is useful beyond the schema. It does not mention error handling or rate limits, but for a simple tool, this is adequate.

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 extremely concise with two sentences: first defines purpose and output, second adds method and parameter option. 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 simple tool with no output schema, the description covers the main purpose, method, and return fields. It could mention domain format validation or limitations (e.g., no IP), but it is sufficiently complete for effective use.

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 coverage is 100%, but the description adds value by listing the parsed fields returned (registrar, dates, etc.) not present in the schema. The raw parameter is also described, echoing the schema but providing context.

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 the action ('Perform a WHOIS lookup') and the specific resource ('domain name'). It lists the returned data fields, which distinguishes it from sibling tools like search_domains or check_domain.

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 provides clear context (direct TCP query, no API key required) and mentions the raw parameter. However, it does not explicitly say when not to use or compare with alternatives, though the purpose is self-evident.

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