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

No annotations are provided, so the description carries the full burden. It does disclose a notable behavior—no browser is launched—but it does not mention whether a network request is made, that many parameters are discarded, or what 'opened' actually means. The schema reveals discards, but the description itself is thin.

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 with no filler. The most important behavioral qualifier ('No browser is launched') appears up front, making the definition easy to scan and digest.

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?

Despite having 9 optional parameters, no annotations, and no output schema, the description is only one sentence. It does not explain return values, side effects, or how the many unrelated-looking parameters (city, ref, json, query) relate to checking a URL. An agent would need to inspect the schema and sibling tools to use it correctly.

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 all 9 parameters are already documented with their own descriptions. The tool description adds no parameter-level meaning beyond the schema, so the baseline of 3 applies.

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?

Description states a specific verb and resource ('Check whether a URL can be opened') and adds a key distinguishing note that no browser is launched, which helps separate it from playwright-url-ok. However, 'opened' is ambiguous—it could mean an HTTP fetch, a shape check, or a routing check—so it stops short of a 5.

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 explicit guidance on when to use this tool instead of siblings like playwright-url-ok, fetch-status, or normalize-url. The only hint is 'No browser is launched,' which implies a lighter-weight check, but there are no stated conditions, exclusions, or alternative tool names.

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