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

With no annotations, the description carries the full burden of behavioral disclosure, but it only says no browser is launched. It does not state whether a network request is made, what the result represents, whether there are side effects, or what the return value is. The 'discarded' parameter behaviors in the schema 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?

The description is two short sentences with no filler. It front-loads the core action and then states the key limitation. Every sentence 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?

There are no annotations, no output schema, and nine optional parameters, yet the description leaves open which parameters to provide, what 'can be opened' means, and what the tool returns. The description is too sparse to fully support correct invocation, especially given the presence of many seemingly unrelated parameters in 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. The tool description adds no parameter-specific meaning and fails to identify which of the nine optional parameters is relevant to checking a URL. However, the schema itself provides descriptions for all parameters, so the description is not solely responsible.

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 verb and resource: checking whether a URL can be opened. The additional 'No browser is launched' helps distinguish it from a likely sibling like playwright-url-ok. However, it does not clarify exactly what 'can be opened' means operationally or differentiate it from other URL-related siblings such as fetch-status or web-fetch.

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 provides no guidance about when to use this tool versus alternatives like fetch-status, web-fetch, or playwright-url-ok. 'No browser is launched' is a behavioral fact, not a usage condition or an explicit alternative. An agent has no basis to decide between this tool and similar siblings.

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