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

With no annotations, the description carries the full burden of behavioral disclosure. It does add the useful trait that 'Page content is not stored,' which implies a privacy-safe operation. However, it does not disclose whether the tool makes network requests, has rate limits, or how it handles errors, leaving critical behavior unspecified.

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 sentences with zero redundancy. The core functionality is front-loaded in the first sentence, and the second sentence adds a meaningful behavioral note without extra fluff. Every word 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?

The description only mentions URL handling, but the schema includes nine optional parameters such as city, feed, json, path, zone, and query. The description fails to explain the purpose of these parameters or how they relate to the stated function, making the tool's actual scope unclear. The absence of an output schema also leaves the return format unspecified.

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 has 100% description coverage, so every parameter is already documented with a clear description. The tool description does not add any additional meaning beyond what the schema provides, so it meets the baseline of 3 for high schema coverage.

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 action: 'Return host, scheme, and HTTP status for a URL.' This is a concrete verb+resource, and it distinguishes the tool from simple URL fetchers by specifying the exact output fields. However, it does not differentiate from sibling tools like fetch-status or normalize-url, which likely have overlapping purposes.

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 on when to use this tool versus alternatives. The description does not mention conditions, exclusions, or alternatives, leaving the agent to infer the appropriate context from the name alone. This is a significant gap given the large sibling list.

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