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

The description discloses that no browser is launched, but the parameter descriptions (e.g., 'discarded after the shape check') suggest a purely syntactic validation, contradicting the stated functional check of opening a URL. The return value or side effects are not described, and the internal inconsistency obscures actual behavior.

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, a single sentence that front-loads the main action. It avoids unnecessary fluff, earning high marks for brevity, even though it sacrifices necessary detail.

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 nine parameters and no output schema, the description is critically incomplete. It does not explain how parameters relate to the check, what the tool returns, or how it differs from sibling tools. The lack of this context makes the tool nearly unusable for an agent.

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?

Each parameter has a description, but they are disjoint from the tool's purpose (e.g., 'Git ref name' and 'City name for a weather hint' have no obvious connection to checking a URL). The descriptions do not specify which parameter is primary or how they are used in the check, providing minimal semantic 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 specific action ('Check whether a URL can be opened') but fails to clarify which of the nine parameters represents the URL, especially since the schema includes unrelated fields like city, zone, and query. The purpose is not fully clear without additional inference.

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 only usage hint is 'No browser is launched,' which implies a lightweight alternative to browser-based tools but does not explicitly state when to choose this over siblings like playwright-url-ok or fetch-status. No prerequisites or limitations are mentioned.

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