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

With no annotations, the description carries the full burden, but it only discloses that no browser is launched. It doesn't say whether a network request is made, what happens if the URL is unreachable, or what the return value is. The parameter descriptions hint at 'shape check' and discarding inputs, but this is vague and not tied to the stated URL-checking 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 brief (two sentences) and front-loads the core action, but it is under-specified for a tool with nine parameters and no output schema. Conciseness is not a problem, but the lack of structure or detail makes it minimally acceptable.

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 tool has nine optional parameters, no output schema, and no annotations. The description does almost nothing to explain what the tool actually does with these parameters, what it returns, or how to interpret results. This is severely incomplete for an agent to correctly invoke the tool, especially given the mismatch between the description and the schema.

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 baseline is 3, but the parameter descriptions are confusing and unhelpful. They say things like 'discarded after the shape check' or 'titles discarded,' but don't explain how these relate to checking if a URL can be opened. The agent cannot determine which parameter to supply for the stated purpose, especially since the tool name suggests only a URL is relevant.

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 clear verb and resource: 'Check whether a URL can be opened.' However, the input schema exposes nine unrelated parameters (city, feed, json, path, zone, query) with descriptions implying a broader shape-checking role, so the stated purpose does not match the schema. It also doesn't differentiate from the sibling 'browser-url-ok' beyond a hint that no browser is launched.

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 this is for lightweight checks without a browser, but it doesn't explicitly say when to prefer this over browser-url-ok, normalize-url, or web-fetch. No exclusions or alternative names are provided, leaving the agent to guess the appropriate context.

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