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

No annotations are provided, so the description must carry the full burden of behavioral disclosure. It only discloses that no browser is launched, but does not explain what 'can be opened' entails (e.g., network request, syntax validation), whether the tool has side effects, or what the return format is. The parameter descriptions hint at discarding data and no disk access, but these are not tied to the tool's core behavior in the main 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?

The description is exceptionally concise, comprising two short sentences that front-load the core purpose and a key constraint. It is easy to parse and contains no filler. However, its brevity leaves out crucial context, so it is not maximally effective.

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 9 optional parameters and no output schema, yet the description does not explain how these parameters relate to the tool's function. For example, it accepts 'city', 'json', and 'path', which are unrelated to checking a URL. The description is too thin to guide an agent on what inputs are relevant or what the tool will do with them, making it incomplete for a tool of this complexity.

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%, with each parameter having a descriptive comment (e.g., 'discarded after the shape check', 'no disk access'). The main description does not add any parameter-specific meaning beyond what the schema already provides, so it meets the baseline for high coverage.

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 action: 'Check whether a URL can be opened' with the explicit constraint 'No browser is launched.' This is a specific verb+resource and provides a clear sense of the tool's function. However, it does not distinguish this tool from its sibling 'browser-url-ok', which likely performs a similar check with a browser, so it lacks sibling differentiation.

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 implies a usage context by stating 'No browser is launched,' suggesting this is the tool to use when a browser is not desired. However, it does not explicitly mention alternatives or conditions for using this tool over others, such as 'browser-url-ok' or 'web-fetch'. The guidance is implied rather than explicit.

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