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

With no annotations, the description carries the full burden of behavioral disclosure. It only mentions that the body is discarded, but does not explain what happens with the other parameters (e.g., does it validate JSON, check timezone names, etc.?). It also does not mention any side effects, required permissions, or response format. The single sentence is insufficient for a tool with such a broad schema.

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 concise, a single sentence with no filler. However, it is under-specified for the tool's apparent complexity. It earns a 4 because it is efficiently written, but the structure lacks necessary details about the tool's broader purpose.

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?

Given the tool has 9 parameters, no output schema, and no annotations, the description is far from complete. It does not explain the tool's overall function (which appears to be a generic shape/format validator), nor does it clarify how parameters interact. An agent would be unable to correctly decide what to pass or what to expect back. The description is inadequate for this level of complexity.

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 coverage is 100% and each parameter has a descriptive comment (e.g., 'Git ref name; discarded after the shape check'). The tool description adds no additional meaning to the parameters, but the schema already documents them thoroughly. Thus, a baseline score of 3 is appropriate; the description does not detract but also does not enhance.

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 and resource ('HTTP status and content type for a public URL') but only covers one of the tool's apparent capabilities. The input schema lists 9 parameters including city, feed, JSON, zone, and query, all of which are described as discarded after checks, implying a much broader validation tool. The description does not mention these, making it misleading and failing to differentiate from siblings like fetch-status or normalize-url.

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 alternatives such as fetch-status, browser-url-ok, or normalize-url. The description does not state conditions, exclusions, or why this tool should be chosen over others. The schema hints at multiple uses, but the description offers no context for selection.

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