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

The description discloses only that the body is discarded and that the URL should be public. It does not mention redirects, error behavior, rate limits, robots, authentication, or the fact that a network request will be made, and no annotations are present to fill that gap.

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 main description is concise and front-loaded, but the overall definition is inflated by nine optional parameters whose descriptions do not align with the tool's purpose. This makes the schema feel padded and unstructured rather than focused.

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 incomplete. It does not explain the expected output structure, error behavior, or the role of each parameter, so an agent cannot confidently determine how to call the tool 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 parameter descriptions are misleading and largely irrelevant to the stated purpose; for example, 'url' is described as 'HTTPS URL to normalize or cite' rather than to fetch, and parameters like city, zone, query, json, ref, and path have no clear relationship to retrieving HTTP status and content type. With no required parameters, the description does not indicate which input actually selects the URL to fetch.

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 that the tool returns HTTP status and content type for a public URL and explicitly says the body is discarded, which distinguishes it from a full-content fetch. However, the schema descriptions for 'url' and other parameters are disconnected from this purpose, creating some confusion in the overall definition.

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 description gives no guidance about when to use this tool versus sibling tools such as fetch-status, browser-url-ok, or normalize-url. It does not mention prerequisites, limitations, or when not to use it, so an agent has little basis for selecting it.

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