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

With no annotations provided, the description carries the full burden of behavioral disclosure. It adds useful behavioral context by mentioning 'offline + IANA fallback', indicating that resolution can work without network and has a fallback for unknown TLDs. It does not, however, describe input normalization, default behavior when q is empty, or error handling, which an agent would need for fully predictable invocation.

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 compact phrase with no wasted words. The core function is front-loaded ('TLD → WHOIS server mapping'), and the operational qualifier ('offline + IANA fallback') is appended efficiently. It earns its length without redundancy.

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?

The tool is simple with one optional parameter, and the output schema exists, so return-value details are not required. The description provides the main domain concept and a key behavioral trait. Still, the lack of explicit parameter semantics and usage alternatives leaves minor but real gaps for an agent deciding how to invoke it correctly.

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 0%, so the description must compensate for the undocumented 'q' parameter. The phrase 'TLD → WHOIS server mapping' suggests 'q' is a TLD, but the description never explicitly defines what format the value should take (e.g., 'com' vs '.com'), whether it is case-sensitive, or what an empty value means. This is a significant gap for a single-parameter tool.

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 specifies the resource and operation: mapping a TLD to its WHOIS server. It is not a tautology, and the phrase 'TLD → WHOIS server mapping' distinguishes this from sibling tools like whois or ripewhois that perform actual WHOIS lookups. However, the operation verb is implied rather than explicit, and no sibling tools are named directly.

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 the tool should be used when you need the authoritative WHOIS server for a TLD rather than querying the WHOIS record itself. It also gives context about offline resolution and IANA fallback. However, it does not explicitly state when to prefer this over related tools such as whois, whois_check, or tldinfo, nor does it provide exclusions.

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