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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so safety is covered. However, the description adds no behavioral context—no rate limits, input format expectations, or return structure. It only names a third-party service, which is not behavior.

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 it is under-specification rather than conciseness. It says nothing beyond repeating the tool name, so the brevity does not serve the agent's needs.

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 one-parameter tool with no output schema, the description should at least state the tool's purpose and expected input. This description provides virtually no context, making it inadequate for the agent to correctly select or invoke the tool, especially amid many DNS-related siblings.

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 only parameter 'target' has no schema description, and the tool description provides zero information about what format or values it expects. With schema description coverage at 0%, the description completely fails to compensate, leaving the agent unable to know if 'target' should be a domain, IP, or something else.

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_lookup lookup' is essentially a tautology, repeating the tool name without specifying what kind of DNS lookup is performed (e.g., forward, reverse, record types). It does not distinguish from sibling tools like reverse_dns or dns_host_search.

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. No mention of target types (domain, IP), expected use cases, or exclusions. The agent is left without any context to choose between this and similar DNS tools.

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