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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does add one useful fact ('Page content is not stored'), but it omits other important behavior: the fact that the tool appears to make an HTTP request to obtain status, and that the schema's many parameters are mostly 'shape checks' with discarded values. The description does not explain what truly happens with non-URL inputs.

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 concise and front-loaded with the main purpose. It uses no unnecessary words. Some would argue it is too thin given the tool's complexity, but as a pure measurement of conciseness it performs well.

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 the tool has 9 parameters, no output schema, and no annotations, the description is far from complete. It fails to clarify which parameter is required or most relevant, how to handle the other parameters (are they optional or ignored?), and what the return format or results will be outside of field names. This leaves an agent guessing on a multi-input tool.

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 description does not add any parameter-level meaning beyond the schema; it mentions 'URL' but does not map it to the `url` property, and it does not clarify how the other eight parameters relate. The schema itself already documents each parameter's role.

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 is specific: 'Return host, scheme, and HTTP status for a URL' clearly states a verb and resource. However, it does not distinguish this from sibling tools like fetch-status or normalize-url, so there is some ambiguity about when to pick this one over them.

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 does not say when to use this tool vs. alternatives. There are siblings such as fetch-status that likely overlap in behavior, but the description gives no context or exclusions to guide selection.

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