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

With no annotations, the description carries the full burden of disclosing behavior. It does provide useful behavioral detail: the return fields and the non-storage guarantee. However, it omits network behavior, redirects, errors, rate limits, authentication requirements, and the fact that many schema parameters are explicitly discarded during shape checks.

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 short sentences with no filler. The core return behavior is front-loaded, and the non-storage caveat is a meaningful secondary statement that earns its place.

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 lack of annotations, the absence of an output schema, the nine optional parameters, and the many overlapping sibling tools, this description is too thin. It does not state the output shape, explain which parameter to use, or differentiate the tool from fetch-status, normalize-url, or web-fetch, leaving an agent with insufficient context for confident selection.

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 coverage for parameters is high, so the baseline is 3. The description adds no parameter-level meaning beyond 'URL' and does not clarify whether the extra parameters (ref, city, feed, json, path, etc.) are alternate modes or irrelevant to this tool. The schema's own parameter descriptions do most of the work.

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 operation: 'Return host, scheme, and HTTP status for a URL.' This is a concrete verb and resource. However, it does not distinguish itself from siblings like fetch-status or normalize-url, and the broad input schema (city, json, path, feed, etc.) makes the tool's actual scope less clear than the URL-only wording implies.

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 about when to use this tool versus alternatives such as fetch-status, browser-url-ok, normalize-url, or web-fetch. The phrase 'Page content is not stored' hints at a privacy-conscious, lightweight option, but it never explicitly states when to choose this tool or when to avoid it.

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