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

With no annotations, the description must disclose behavioral traits. It only says 'No browser is launched,' which is a minor behavioral note. It does not explain what 'opened' means (e.g., network request, syntax check), nor does it mention that most parameters are discarded, which is a significant behavioral trait inferred from the schema descriptions. The description is far from sufficient for a tool with this many parameters.

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 extremely short (one sentence), but it is under-specified rather than concise. It omits essential information about behavior and parameters. Conciseness should be balanced with completeness; here the brevity hurts clarity.

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 parameters, no output schema, and no annotations, the description is grossly incomplete. It doesn't explain what the tool returns, how parameters interact, or what 'opened' actually entails. An agent would have almost no idea how to call this tool correctly or what to expect.

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 schema already documents each parameter. The description adds no parameter-level information, but the baseline of 3 applies because the schema does the heavy lifting. The description does not compensate for any ambiguity, but it also doesn't contradict the schema.

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 action: check whether a URL can be opened, and adds that no browser is launched. However, it does not distinguish this from sibling tools like fetch-status, playwright-url-ok, or normalize-url, so an agent cannot tell which tool to pick based on this description alone.

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?

There is no guidance on when to use this tool versus alternatives. No exclusions, no context, no conditions. The description merely states the action without any recommendation or differentiation, leaving the agent to guess.

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