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

With no annotations, the description carries the behavioral burden. 'No browser is launched' is a meaningful behavioral disclosure and prevents an agent from expecting a browser session. However, it does not state whether a network request is made, whether inputs are retained, or what result is returned.

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 sentences, no filler, and the key behavioral qualifier follows immediately after the purpose. 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?

The tool has nine optional parameters, no annotations, and no output schema, yet the description only covers the URL-checking case. It does not explain the remaining parameters, the return value, or when the tool should be preferred over sibling tools, so an agent would be under-informed for complex invocations.

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 description adds at most a general sense that 'url' is the value being checked, but it provides no additional meaning for the eight other optional parameters and does not clarify their relation to the stated purpose.

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 uses a specific verb and resource: 'Check whether a URL can be opened.' It is clear at a glance, and 'No browser is launched' adds a useful qualifier. However, it does not distinguish this tool from similarly named siblings like browser-url-ok, and the wide input schema suggests the tool may do more than the one-line purpose states.

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?

There is no explicit when-to-use or when-not-to-use guidance and no mention of alternatives such as browser-url-ok, fetch-status, or web-fetch. The only hint is 'No browser is launched,' which implies a lightweight check but does not tell the agent which sibling to choose.

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