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

With no annotations provided, the description carries the full burden of disclosing behavior. It only reveals that no browser is launched, but does not state whether the tool performs a network request, what 'ok' means (HTTP 200? URL syntax?), or what side effects or side-stepping it might do. It also entirely ignores the nine parameters, several of which are described as 'discarded' in the schema, creating a disconnect between the description and the actual inputs.

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 with no redundant filler. It front-loads the core action and adds a key distinction. It is appropriately concise, though the brevity contributes to the lack of completeness on other dimensions.

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?

Given the tool has nine parameters, no output schema, and no annotations, the description is severely incomplete. It does not explain what the tool returns, how to interpret a positive or negative result, or why it accepts unrelated parameters. The description's focus on URL while the schema includes many other input types creates a significant gap that an agent cannot resolve without external knowledge. More details on the return value and parameter relationships are essential.

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 parameters themselves are documented in the input schema. The description adds no additional meaning to the parameters; it doesn't even mention them, which is odd given that the tool name and description focus solely on URLs while the schema includes unrelated fields like city, zone, and query. The baseline of 3 is appropriate because the schema does the heavy lifting, but the description could have clarified which parameters are relevant to the URL check.

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 clear verb ('Check') and resource ('a URL can be opened'), and the 'No browser is launched' clause distinguishes it from sibling playwright-url-ok, which presumably does launch a browser. However, it doesn't clarify whether 'can be opened' means a network request or just a URL shape check, leaving some ambiguity about its exact function compared to tools like fetch-status or normalize-url.

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 offers a single negative clue ('No browser is launched') that hints at when not to use it (when a full browser render is needed), but it does not explicitly state when to prefer this tool over alternatives like fetch-status or normalize-url, nor does it give any context for its many non-URL parameters. There is no clear 'use this when...' or 'instead of...' guidance.

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