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

With no annotations, the description must carry the full behavioral burden. It does disclose that query and fragment are dropped, which is useful. However, it fails to clarify which of the nine parameters is the URL input, what happens to the other eight parameters, whether the host is lowercased, or how invalid URLs are handled. This is only 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 a single sentence, very concise and front-loaded with the core purpose. However, it is so brief that it omits critical details about input selection and behavior. While not verbose, it under-specifies, so it is not an ideal structure. A score of 3 reflects that it is concise but incomplete.

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 complexity of 9 parameters, no annotations, and no output schema, this description is severely inadequate. The agent cannot determine which parameter to use, what the output format is, or what the other parameters are for. The description provides almost no context to support correct invocation, making it nearly useless.

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 documents each parameter. However, the tool description does not add meaning beyond that—it says 'for a URL' but does not specify which parameter is the URL. The schema itself lists many discarded parameters, but the description does not direct the agent to the correct one, creating ambiguity. Baseline is 3 for high coverage, but the description fails to clarify the primary input, so a 2 is appropriate.

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 action: return origin, host, and path for a URL, and explicitly drops query and fragment. This is clear and distinct, though it does not name sibling tools to differentiate. The verb and resource are precise, so it earns a 4 rather than 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?

No guidance is given about when to use this tool versus the many URL-related siblings (e.g., browser-url-ok, fetch-status, domain-shape). There is no mention of alternatives, exclusions, or context where this tool is preferred. The description implies a simple normalization use case but does not explicitly state it.

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