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 does state that 'Page content is not stored,' which is a meaningful privacy guarantee. However, it does not mention any other side effects, permission requirements, rate limits, or the fact that json input is discarded after validation (which is only in the schema). This is a partial disclosure.

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 extremely concise—two sentences with no filler. The primary action is front-loaded, and the privacy note is a useful addition. However, the brevity comes at the cost of missing critical parameter context, so while it is concise, it is not sufficiently informative.

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, no annotations, and no output schema, the description is inadequate. It explains the purpose of url but leaves host, json, and zone ambiguous. It also does not describe the return structure or any error conditions. An agent would not know how to properly call this tool for a task involving JSON or timezone parameters.

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 the baseline is 3. The description adds minimal meaning beyond the schema: it clarifies that the url parameter is used to return host/scheme/status, but it does not explain how host, json, and zone are used together or what the expected output format is. The schema descriptions are self-sufficient, so the description does not need to compensate, but it also does not add significant value.

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 clear verb and resource: 'Return host, scheme, and HTTP status for a URL.' This distinguishes it from siblings like normalize-url and validate-json in that it focuses on URL metadata rather than URL rewriting or JSON validation. However, it does not mention the json or zone parameters, which obscures the full scope of the tool.

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 provided on when to use this tool versus alternatives. It does not reference sibling tools like normalize-url or validate-json, nor does it describe scenarios where this tool would be preferred. An agent is left to infer usage from the name and partial description.

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