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

With annotations already indicating readOnlyHint=maybe and sideEffectsHint=likely, the description adds the key negative behavior 'No browser is launched' but leaves unclear whether a network request is made or what 'opened' implies (status code, DNS, 2xx check).

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, purpose stated first and a key behavioral constraint second. No filler or repetition of schema details.

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?

With seven parameters and no output schema, an agent cannot determine what the tool returns or how 'can be opened' is decided. The odd mix of params (city, json, path) is not explained, so the description feels incomplete for real use.

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 only 55%, so the description should compensate, but it adds no parameter-level guidance. It mentions 'URL' while the schema includes unrelated params like city, json, and path, leaving mapping ambiguous.

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?

States a specific verb ('Check') and a clear resource ('whether a URL can be opened'), and the second sentence ('No browser is launched') distinguishes it from sibling tools like playwright-url-ok that actually launch a browser.

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?

Implies a lightweight check without browser side effects, but never explicitly names alternatives or conditions for when to use it instead of normalize-url, fetch-status, or playwright-url-ok.

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