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

Annotations clearly indicate a read-only, idempotent, non-destructive operation, but the description adds no behavioral context beyond the name. It does not mention the external HackerTarget service, rate limits, or any unusual behavior. The description provides zero value beyond the annotations, so the score is below the baseline 3.

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 short, but this is under-specification rather than effective conciseness. It contains only three words and does not 'earn its place' – it adds no information beyond what is already known from the tool name and title.

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?

With no output schema, a single undocumented parameter, and no behavioral context, the description is severely incomplete. The agent cannot tell what the tool does, what input to provide, or what to expect in the response. This is as inadequate as a one-word description.

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 schema has 0% description coverage for the required 'target' parameter, and the description gives no hint about what 'target' should be (e.g., domain, IP, or URL). The agent has no information about parameter format or semantics, making this parameter effectively undocumented.

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 'HackerTarget whois lookup' essentially restates the tool name and title. It provides no specific detail about what the lookup entails, what data is returned, or how it differs from sibling tools like dns_lookup or reverse_dns. This is a tautology rather than a clear purpose statement.

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?

There is no guidance on when to use this tool versus alternatives. The description does not mention any exclusions, prerequisites, or scenarios where this tool is preferred. The agent is left without context for selecting this tool among many similar network-lookup tools.

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