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

With no annotations, the description must carry behavioral disclosure. It only states that no browser is launched, but doesn't explain whether a network request occurs, how 'can be opened' is determined, or what happens to the many other parameters. The schema's 'discarded' hints are not reflected in the description.

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 a single terse sentence, which is concise but under-specified for a tool with nine parameters. It lacks structure or prioritization, and the one statement provided doesn't earn its place given the complexity.

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 no annotations, no output schema, and a nine-parameter input. The description provides almost no context: no return value, no side effects, no indication of which parameters matter, and no relationship to siblings. This is wholly inadequate for an agent to call 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 coverage is 100% so the baseline is 3, but the description adds nothing about parameters and the schema descriptions themselves are misleading (e.g., 'url' is described as 'HTTPS URL to normalize or cite' rather than being checked). The description does not clarify that 'url' is the primary parameter, leaving the agent uncertain which field to supply.

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 specific action ('check whether a URL can be opened') but the input schema includes nine parameters with many unrelated to URLs (city, zone, json, path, query). This mismatch makes the tool's true scope ambiguous, and no differentiation from siblings like normalize-url or playwright-url-ok is provided.

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 no guidance on when to use this tool versus alternatives, no exclusions, and no context about which sibling it complements or replaces. An agent is left to infer entirely from the name.

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