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

With no annotations, the description carries the burden and does disclose a key behavior: the response body is discarded. It also limits scope to public URLs, but it omits other relevant behaviors such as redirect handling, timeouts, errors, or output format.

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?

Eleven words in two sentences, with the core output statement first and no filler. Every part 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?

Despite the clear one-line purpose, the definition is incomplete for safe selection and invocation: with 9 optional parameters, no output schema, and many similar siblings, the agent is left to guess which parameter to supply and how this tool differs from fetch-status or browser-url-ok.

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; the tool description adds little beyond 'public URL.' It does not clarify which parameter should receive the URL or how the nine optional fields relate to the stated fetch 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 names a concrete action and outcome: it fetches a public URL and returns HTTP status and content type, with the body discarded. This is not a tautology, but it does not explicitly distinguish it from similar siblings 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 for header/availability checks rather than content retrieval. However, it gives no explicit when-to-use or when-not-to-use guidance and never mentions alternative tools.

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