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 only states that page content is not stored, but does not disclose that most parameters are discarded after shape checks, that no disk access occurs, or any other side effects or constraints. This is insufficient for a tool with 9 optional parameters.

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 a single sentence that front-loads the core function and includes a relevant caveat. It is appropriately concise with no waste, though it could be slightly more informative given the tool's complexity. It earns a 4 because it is well-structured and efficient.

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 annotations or output schema. It lacks usage guidance, behavioral details about the discarded parameters, and any mention of what happens on invalid inputs. An agent would need to inspect the schema to understand the tool's full behavior, which is not ideal.

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% because every parameter has an explicit description. The tool description adds no extra meaning beyond the schema; it only implies the 'url' parameter is the primary input. Per the rubric, baseline is 3 when schema coverage is high, and no additional compensation is provided.

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'), resource ('URL'), and output ('host, scheme, and HTTP status'). The additional note 'Page content is not stored' clearly differentiates it from content-fetching siblings like web-fetch or browser-url-ok, making the purpose unambiguous.

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 provides no guidance on when to use this tool versus alternatives. It does not mention conditions, exclusions, or reference sibling tools. An agent has no basis for selecting this over fetch-status or normalize-url based on the description alone.

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