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

With no annotations, the description must carry the full burden of behavioral disclosure. It only reveals that no browser is launched; it does not say whether a network request is made, whether it returns a boolean, or whether non-URL parameters are discarded. The schema's 'discarded after the shape check' hints are not reflected in the 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 short, front-loaded sentences with no redundancy. However, brevity comes at the cost of critical information, so it is not a perfect 5.

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 9 parameters, no annotations, and no output schema, an agent cannot tell what to pass, what result to expect, or whether the check is offline vs network-based. The definition is too sparse for correct 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 coverage is 100%, so each parameter has a description; baseline 3 applies. The tool description adds nothing about how to fill parameters, and the 'url' parameter's schema text ('normalize or cite') conflicts in spirit with the tool's 'check whether a URL can be opened', so the description fails to reinforce which parameter is the target.

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 action ('Check whether a URL can be opened') and a target resource (URL), and the second sentence distinguishes it from browser-launching tools like playwright-url-ok. However, it leaves unstated whether this is a syntax check, DNS check, or HTTP reachability check, and it does not clarify the relationship to the many other parameters.

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 on when to choose browser-url-ok over siblings like fetch-status, normalize-url, or playwright-url-ok. The only implicit hint is 'No browser is launched', which excludes browser automation but does not state the appropriate use case or alternatives.

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