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

With no annotations, the description must disclose behavioral traits itself. It only mentions 'HEAD a public URL and return status only,' which is minimal. It does not explain the side effects (though likely none), the handling of the other schema parameters (many are 'discarded' per schema descriptions), or any potential limitations. The rich schema suggests broader behavior that is left entirely undisclosed.

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 sentence, which is concise, but it does not add value beyond a simple purpose statement. It is not front-loaded with critical scope or behavioral hints, and the brevity borders on under-specification rather than efficient wording. It earns a middle score for not being verbose while still lacking substance.

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 nine optional parameters, no output schema, and no annotations, the description is severely inadequate. It does not explain how the different parameter types relate to the stated purpose, when to use them, or what the full range of behavior is. The description only covers the URL case and ignores the other schema fields, leaving the agent without sufficient context to use the tool correctly for non-URL inputs.

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 100%, meaning every parameter already has a textual description in the schema. The tool description adds no additional parameter semantics, so it neither improves nor degrades the schema's coverage. A baseline of 3 is appropriate since the schema does the heavy lifting.

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 states a specific verb ('HEAD') and resource ('public URL') and indicates the output ('status only'), which gives a basic sense of purpose. However, it does not differentiate from sibling tools like 'web-fetch' or 'browser-url-ok' that also interact with URLs, and it fails to account for the nine diverse input parameters in the schema, making the stated purpose incomplete and potentially misleading.

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 on when to use this tool versus the many siblings (e.g., 'normalize-url', 'playwright-url-ok', 'validate-json'). The description does not mention any conditions, exclusions, or alternatives, leaving the agent to infer usage context from the schema alone.

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