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

Annotations (readOnlyHint, openWorldHint, idempotentHint) indicate a safe read-only operation, but the description itself adds no behavioral context. It does not explain how the lookup behaves, what data is returned, or any limitations.

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 one short sentence, but it is under-specified rather than concise. It omits essential meaning and does not communicate the tool's purpose or usage effectively.

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 tool with a single parameter and no output schema, this description is far too minimal. It gives the agent no understanding of what input to provide or what output to expect, making correct invocation nearly impossible.

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 defines a single 'target' string with no description, and the tool description provides zero explanation of what 'target' should be (e.g., a domain name, IP address, or hostname). With 0% schema coverage, the description fails to compensate.

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 dns_host_search lookup' essentially restates the tool name with a generic verb. It fails to specify what is actually searched or what the tool returns, and it does not differentiate it from sibling DNS tools like dns_lookup or reverse_dns.

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?

No guidance is provided about when to use this tool versus alternative lookup tools. There is no mention of use cases, prerequisites, or exclusions.

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