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

With no annotations present, the description carries the full burden. It does disclose one important behavioral trait—dropping query and fragment—which adds real value. However, it remains silent on error handling, output format, and the odd fact that most schema parameters are accepted and then discarded; those details live only in the schema, not in the behavioral description.

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?

Two compact sentences with no filler. The main output contract is front-loaded and the key omission behavior is stated in a single clause, making it easy to parse.

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?

The core extraction behavior is clear, but the description leaves the return format unspecified, says nothing about failure cases, and does not reconcile the presence of many unrelated discard-only parameters. Without annotations or an output schema, these gaps make the description adequate but incomplete for confident invocation.

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 descriptions already cover all eight parameters in detail, including discard semantics for seven of them, so schema coverage is high. The description adds no parameter-specific meaning; it doesn't even point to the 'url' parameter as the primary input. With schema carrying the weight, a baseline 3 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 verb 'Return' with a clear resource ('origin, host, and path for a URL') and explicitly names what is omitted ('Query and fragment are dropped'). This distinguishes it from sibling tools that validate or fetch URLs rather than parse them.

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 siblings like fetch-status, playwright-url-ok, or domain-shape. There is no mention of alternatives, exclusions, or conditions, leaving the agent to infer usage entirely from the stated purpose.

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