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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It does reveal one meaningful trait: the tool does not launch a browser, which prevents a likely misinterpretation of 'browser-url-ok.' Still, it says nothing about whether a network request is made, whether the operation is read-only, what the return value looks like, or how the non-URL parameters are handled.

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 two short sentences with no filler. It states the core action first and then immediately adds the most important caveat. Every word earns its place.

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 seven heterogeneous parameters and no output schema, the description is far too thin for an agent to invoke the tool reliably. It does not explain what 'ok' means as a result, which parameters are required or mutually exclusive, whether the extra parameters are discarded or meaningful, or how this tool relates to the many sibling tools with similar names. The agent is left with too much ambiguity.

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 schema description, so the baseline for parameter coverage is moderate. However, the main description only discusses URLs, while the schema includes ref, city, feed, json, and path, and even the url parameter is described as 'normalize or cite' rather than 'open.' The description adds no useful parameter-level meaning and actually creates confusion about why those other fields exist.

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 names a concrete verb and resource: 'check whether a URL can be opened' and adds a useful exclusion with 'No browser is launched.' This helps differentiate it from a browser-launching sibling tool. However, 'can be opened' is left undefined, and the schema contains multiple unrelated parameters that make the tool's true scope less clear than the description implies.

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 browser is launched' implies this is a non-browser validation check, which gives the agent some usage context. But the description never names alternatives like playwright-url-ok, web-fetch, or fetch-status, nor does it explain when to choose this tool over them. 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.