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 side effects and behavior. It only says no browser is launched, but does not clarify whether network requests are made, whether data is stored, or what side effects might occur. The schema descriptions hint at 'discarded after shape check' but the tool description itself is insufficient.

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 concise and front-loaded, stating the core purpose in the first sentence. It avoids unnecessary verbosity, though it omits important usage and behavioral 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?

The tool has 9 optional parameters, no required parameters, and no output schema, yet the description gives almost no context about how to invoke it, which parameter to provide, what result to expect, or how it relates to sibling tools. This is inadequate for a tool with this level of input complexity.

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?

The schema has 9 optional properties with descriptions, but they are confusing and largely unrelated to the stated purpose of checking whether a URL can be opened. For example, 'url' says 'HTTPS URL to normalize or cite' rather than 'open', and parameters like 'ref', 'city', and 'zone' seem irrelevant. The description adds no clarification about which parameter is the actual URL to 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 clearly states a specific action ('Check whether a URL can be opened') and adds a meaningful qualifier ('No browser is launched'). It is reasonably clear, though 'can be opened' is slightly ambiguous about whether this means syntactic validity, reachability, or something else.

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 gives no explicit guidance about when to use this tool versus its many siblings (e.g., playwright-url-ok, fetch-status, normalize-url). The 'No browser is launched' note implies a distinction but does not state it clearly or mention alternatives.

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