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

No annotations are provided, so the description carries the full burden. It discloses 'Page content is not stored,' which is useful, but it does not explain the behavior for the other parameters (e.g., city, feed, json) or whether they are processed or ignored. It also doesn't mention any side effects, rate limits, or auth requirements. For a tool with 9 parameters, this is a significant gap.

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, which is concise, but it omits essential context about the tool's multi-parameter nature. It front-loads the URL-specific output but does not acknowledge the other parameters, making it misleading in its brevity. It is not structured to help an agent understand the tool's full scope.

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?

For a tool with 9 optional parameters, no output schema, and no annotations, the description is severely incomplete. It explains only the URL-related behavior and leaves the purpose and effect of the other 8 parameters unexplained. An agent cannot confidently call this tool correctly without opening the schema, and even then the relationship between parameters is unclear.

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%, with each parameter having a description (e.g., 'discarded after the shape check'). The tool description adds no parameter information beyond what the schema already provides. Since the schema does the heavy lifting, a baseline score of 3 is appropriate; the description does not compensate for any gaps.

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 resource ('host, scheme, and HTTP status for a URL'), which clearly distinguishes the core action. However, it ignores the other 8 parameters in the schema, so the overall purpose is only partially clarified. Siblings like normalize-url and fetch-status are not explicitly differentiated, but the stated output is specific enough.

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 is given on when to use this tool versus alternatives. With 27 sibling tools including normalize-url, fetch-status, and browser-url-ok, an agent cannot infer the selection criteria. The description does not mention any conditions, exclusions, or alternative tools.

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