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

With no annotations, the description carries the behavioral disclosure burden. It adds one useful behavioral fact: 'Page content is not stored.' However, it does not mention whether the tool fetches the URL, what side effects occur, failure behavior, or authentication needs, so transparency is only partial.

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 only two sentences, front-loads the core purpose, and every sentence adds value. There is no redundant wording or filler.

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 covers the primary output and a key privacy trait, and the schema covers parameters. However, with no output schema, no annotations, and a large sibling set, the lack of usage context and return-format details leaves the tool only minimally complete.

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 each parameter, including discard behavior for ref, city, feed, and json. The description adds no parameter-level detail beyond identifying URL as the relevant input. With high schema coverage, the baseline of 3 is appropriate.

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 a specific verb and resource: 'Return host, scheme, and HTTP status for a URL.' It is easy to understand what the tool produces. However, it does not explicitly differentiate itself from sibling tools like fetch-status or normalize-url, so it falls just 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?

There is no guidance about when to use this tool versus the many siblings, nor any mention of exclusions or alternatives. The phrase 'Page content is not stored' hints at a privacy characteristic but does not help an agent choose between citation, fetch-status, normalize-url, or web-fetch.

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