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 does disclose that page content is not stored, which is a positive behavioral note. However, it does not explain the primary action (e.g., that it likely makes an HTTP request), any side effects, error handling, or limitations. The note about not storing content is the only behavioral disclosure, which is insufficient for a tool that interacts with external URLs.

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 filler. The primary purpose is front-loaded, and the behavioral note is concise. It is exactly as short as needed and no longer.

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?

Given the tool has 4 parameters (none required), no output schema, and no annotations, the description is far too sparse. It does not explain the role of each parameter, the expected output format, or how the tool differs from the 10 siblings. An agent would not have enough information to correctly invoke the tool with the right parameters or interpret the result. The description should at least clarify the relationship of json and zone to the core function.

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?

Although schema description coverage is 100%, the description adds no meaning beyond the schema and fails to reconcile the parameters with the stated purpose. The schema lists url, host, json, and zone, but the description only mentions returning host, scheme, and status for a URL. It does not explain how json (JSON validation) or zone (timezone) relate to the tool's core function, leaving an agent confused about when to pass these parameters. This is a significant semantic gap.

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 and resource: 'Return host, scheme, and HTTP status for a URL.' It also adds a distinguishing behavior note ('Page content is not stored') that separates it from tools that might fetch or store content. It does not explicitly name sibling tools, so it doesn't fully differentiate from alternatives like normalize-url or http-403, but the core purpose is clear and specific.

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 any conditions, prerequisites, or exclusions. An agent would have no idea whether to pick this over normalize-url, http-403, or status-catalog 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.