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

With no annotations, the description carries the full burden and does disclose a key behavior: the response body is discarded. It does not explain redirect handling, timeout behavior, error responses, or how content type is derived, leaving meaningful behavioral gaps.

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 two short sentences with no filler. The main behavior is front-loaded, and 'Body discarded' is a useful, non-redundant addition.

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?

Despite nine optional parameters and no output schema or annotations, the description provides only a terse overview. It does not tell the agent which parameters to populate, what the result format looks like, or how to distinguish this tool from fetch-status and other URL-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?

Schema description coverage is 100%, so each parameter already has its own description. The tool description adds little parameter-level meaning and does not clarify how the many unrelated-looking parameters (city, json, zone, query) relate to the stated URL-fetching behavior.

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 clearly states the tool's function: return HTTP status and content type for a public URL while discarding the body. It is specific about resource and behavior, though it does not explicitly differentiate from sibling tools like fetch-status or browser-url-ok.

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?

The phrase 'public URL' and 'body discarded' imply the tool is appropriate when only status/content type are needed, and not when page content is required. However, it does not explicitly name alternatives or give when-to-use versus when-not-to-use guidance relative to its many sibling tools.

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