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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does disclose one useful trait, 'No browser is launched,' but it does not explain how the check actually happens, whether any network request is made, what 'ok' means, or what side effects or outputs can be expected.

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 very short and front-loaded, with the core action stated first. The second sentence about not launching a browser is informative and earns its place. It is slightly under-specified for the number of parameters, but as a concise statement it is 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?

For a tool with 9 optional parameters, no output schema, no annotations, and many overlapping siblings, this description is incomplete. It does not clarify which parameters are relevant, what the tool returns, or how it differs from browser-url-ok and fetch-status, so an agent risks invoking it incorrectly.

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?

All 9 parameters have descriptions in the input schema, so schema coverage is 100% and the baseline is 3. The tool description adds no parameter-level detail beyond mentioning 'URL,' but it does not need to compensate because the schema already documents the parameters clearly.

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 action ('Check whether a URL can be opened') and a clear resource, which is enough to understand the core purpose. It also gives a distinguishing behavioral note ('No browser is launched') that helps separate it from browser-url-ok, though it does not explicitly name the sibling.

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 when to use the tool: whenever a caller needs to know whether a URL can be opened. However, it offers no explicit guidance about when not to use it or which sibling tool (browser-url-ok, fetch-status, web-fetch) should be preferred in other situations.

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