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

With no annotations, the description carries the full behavioral burden. It does disclose a meaningful behavior: the body is discarded, so the tool is not suitable for content extraction. Still, it omits details such as redirect handling, timeout behavior, authentication requirements, or any error/response format, which leaves notable gaps for a network tool.

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: it states the core result, scopes it to public URLs, and discloses the body-discarding behavior. The most decision-relevant constraint is front-loaded, and every word earns its place.

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 no annotations, no output schema, nine optional parameters, and many URL-related siblings, the description is too thin. It does not describe the return shape, error behavior, redirect policy, or how the other parameters relate to the stated fetch purpose, so an agent cannot fully predict the tool's behavior or confidently select it among alternatives.

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 the baseline is 3 even without additional parameter explanation in the tool description. The description does not add semantic value beyond the schema, and it fails to clarify why a web-fetch tool has eight non-URL parameters, leaving agents to rely entirely on the individual parameter descriptions.

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 adds the important constraint that the body is discarded. It is specific about the resource and result, but it does not explicitly differentiate itself from URL-related siblings such as fetch-status or browser-url-ok, so it stops short of a 5.

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 for lightweight reachability/content-type checks and not for retrieving page content. However, there is no explicit guidance about when to prefer this tool over alternatives like fetch-status, browser-url-ok, or playwright-url-ok, and no when-not-to-use exclusions beyond the discarded body.

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