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

With no annotations provided, the description carries the full burden. It discloses that the body is discarded, which is a useful behavioral note, and indicates it works on public URLs only. However, it does not mention timeouts, redirects, error handling, or what happens with non-HTTP URLs, leaving some behavioral uncertainty.

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 concise sentences with no filler, front-loading the primary purpose. It is efficient and easy to parse.

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 tool has 9 optional parameters and no output schema, and the description is very minimal. It only mentions URL fetching, but the schema includes parameters for city, zone, json, path, etc., which are not explained in the description. This leaves the agent confused about how to use the tool for non-URL inputs and what the tool actually does with them. Given the complexity of the parameter set, the description is insufficient for complete understanding.

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 input schema already describes all 9 parameters with 100% coverage, so the description adds no extra parameter semantics. The baseline of 3 applies; the description does not clarify which parameter is primary or how the many parameters relate to the stated purpose of fetching a URL, which is a slight gap given the large parameter count.

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 states a clear purpose: fetching a public URL and reporting HTTP status and content type, with the body discarded. It is specific about the verb and resource, though it does not explicitly distinguish it from sibling tools like fetch-status, which might do the same. The body-discard note adds a distinguishing detail.

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 provides no guidance on when to use this tool instead of alternatives such as fetch-status, browser-url-ok, or normalize-url. It does not mention any conditions or exclusions, leaving the agent without direction on tool selection.

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