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

With no annotations, the description carries the full disclosure burden. 'Body discarded' is a useful and non-obvious behavioral detail, and the output is described as HTTP status and content type. It omits other behavioral traits such as redirect handling, error representation, and which of the nine parameters actually trigger a fetch.

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?

Two short sentences with no filler. The core outcome is front-loaded, and the body-discard caveat is given immediately after, making the tool's scope clear at a glance.

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?

The description is too thin for a tool with nine optional parameters, no annotations, and no output schema. It does not explain which parameters are relevant, what the return format looks like, how errors are surfaced, or how this tool relates to siblings like fetch-status and normalize-url. The core use is understandable, but reliable selection and invocation across the sibling set is not fully supported.

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 input schema already documents all nine parameters. The description adds no parameter-level meaning beyond the phrase 'public URL', which maps loosely to the url parameter. This is a baseline-3 situation where 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 clearly states the tool returns HTTP status and content type for a public URL and that the body is discarded. This is a specific resource-plus-outcome statement, but it does not explicitly distinguish web-fetch from sibling tools like fetch-status or playwright-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 'for a public URL' implies when the tool should be used, and 'Body discarded' signals that it should not be used when body content is needed. However, there is no explicit guidance about when to prefer this tool over the many similar sibling tools.

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