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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, which covers safety. The description adds no additional behavioral context such as external API dependencies, rate limits, or output format, providing no value beyond the annotations.

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 brief, but this is under-specification rather than conciseness. It is not a full sentence and lacks any informative structure, offering no useful content beyond the tool name.

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?

Even for a simple tool, the description should at least clarify what target refers to and what the output will be. The lack of an output schema increases this need, but the description provides neither, making it incomplete for an agent to use 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?

The only parameter 'target' is a required string, but the description does not explain what it means (e.g., a domain, URL, or IP). With schema description coverage at 0%, the description fails to compensate, leaving the parameter's semantics completely unexplained.

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 http_headers lookup' essentially restates the tool name with the verb 'lookup' and the provider, but does not explain what http_headers does (e.g., retrieving HTTP headers for a given target). It does not distinguish from sibling tools beyond the name, making it a near-tautology.

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 about when to use this tool versus alternatives like dns_lookup or whois. The description provides no context, prerequisites, or examples of appropriate use.

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