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

With no annotations, the description carries the behavioral burden. It does add a meaningful privacy/retention note: 'Page content is not stored,' and 'Return ... HTTP status' implies an outgoing read-only request. However, it does not mention potential side effects, authentication needs, rate limits, or failure behavior, so transparency is only partially addressed.

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 no filler. The primary behavior is front-loaded, and the second sentence adds a concise, valuable privacy note. Every part 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?

Despite the concise core, the tool has nine optional parameters with no required ones, and the description does not clarify which parameter is the actual operational input or that the other parameters are effectively ignored. Without an output schema or annotations, an agent may be uncertain how to invoke this tool correctly, especially given the many sibling tools with overlapping URL-checking capabilities.

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 schema already documents all nine parameters, including their meanings and discard behavior. The description mentions 'URL' only at a general level and adds no parameter-specific detail, so it neither improves nor harms semantics beyond the schema baseline.

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 concrete action and output: 'Return host, scheme, and HTTP status for a URL.' This is specific enough to distinguish it from vague 'process' tools, and the phrase 'for a URL' clarifies the resource. However, it does not explicitly differentiate from siblings like fetch-status or normalize-url, so it falls short of a 5.

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 gives no guidance about when to use this tool versus the many sibling tools, such as fetch-status, browser-url-ok, or normalize-url. There are no exclusions, prerequisites, or alternative conditions mentioned, leaving the agent to infer the use case from the tool name and description alone.

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