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

No annotations are provided, so the description bears the full burden of behavioral disclosure. It only reveals that no browser is launched; it does not disclose whether a network request is made, what the tool returns, whether the operation has side effects, or what 'opened' actually means. One useful fact is present, but key behavioral traits are missing.

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, front-loaded with the primary action and followed by a key caveat. There is no filler, redundancy, or wasted wording.

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 nine parameters, no annotations, and no output schema, the description is too thin. It does not explain the result format, the relevance of the non-URL parameters, or how this tool differs from siblings beyond the no-browser note. The schema covers parameter names, but the overall calling context is incomplete.

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%: every parameter has a descriptive entry, so the schema carries the parameter semantics. The prose description adds no parameter-level meaning, which is acceptable given the high schema coverage baseline.

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 specific action and resource ('Check whether a URL can be opened') and adds the no-browser caveat, which hints at differentiation from sibling tools like browser-url-ok. However, 'can be opened' is left vague: it could mean syntax validation, reachability, or Playwright compatibility, so the core purpose is not fully precise.

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 phrase 'No browser is launched' implies this is a lightweight or non-invasive check and suggests a contrast with browser-url-ok, but it never explicitly states when to use this tool versus alternatives or when not to use it. Usage context is inferable rather than direct.

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