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 one behavior ('Page content is not stored') but omits critical aspects such as whether network requests are made, if it is read-only, error handling, or any side effects. This is insufficient for a tool that likely performs HTTP requests.

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 no fluff. The purpose is front-loaded in the first sentence, and the behavioral note in the second adds value without redundancy.

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 is incomplete for a tool with 9 parameters and no output schema. It does not explain how the many seemingly unrelated parameters (city, zone, json) relate to the core URL function, nor does it describe the exact output structure or error behavior. An agent would lack critical information to call this correctly.

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 each parameter is already documented. The tool description adds no additional meaning beyond the schema, but does not contradict it. The baseline of 3 applies since the schema handles parameter explanation.

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 specific verb ('Return') and the exact data points (host, scheme, HTTP status) for a URL, which clearly distinguishes it from siblings like normalize-url or web-fetch. The additional note that page content is not stored further differentiates it from tools that fetch and retain content.

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 explicit guidance on when to use this tool versus alternatives like fetch-status or browser-url-ok. The description does not mention conditions for selection, exclusions, or context where a sibling would be more appropriate.

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