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

No annotations provided, so the description carries the burden. It discloses that page content is not stored, but it omits the fact that most input parameters are discarded after shape checks, and it doesn't describe the actual behavior for non-URL inputs. The description's narrow claim conflicts with the schema's broader scope.

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 and concise, but it is misleadingly narrow. It front-loads a specific behavior that is not the whole picture, and it doesn't structure the information to reflect the tool's actual complexity.

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?

With 9 optional parameters, no output schema, and no annotation context, the description is woefully incomplete. An agent cannot know what to expect for other inputs, what the return format is, or how this relates to sibling tools. It only covers a single URL case.

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 baseline is 3, but the description adds no parameter-level meaning. It only mentions URL behavior, leaving the other 8 parameters unexplained. The description fails to clarify which parameters are relevant for the stated purpose and how they interact.

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 function ('Return host, scheme, and HTTP status for a URL') but the input schema reveals a much broader set of validation behaviors (city, feed, JSON, etc.) not mentioned. This misrepresents the tool's scope and fails to distinguish it from siblings like fetch-status or normalize-url.

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?

No guidance on when to use this tool vs alternatives like fetch-status or normalize-url. The description doesn't mention any conditions or exclusions.

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