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

With no annotations, the description carries the full burden of behavioral disclosure. It only states 'No browser is launched,' which is a negative claim. It does not clarify whether the tool makes network requests, performs local checks, or what side effects occur. The parameter descriptions hint at various checks (e.g., 'discarded after the shape check') but the main description fails to explain the actual behavior.

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 concise (one sentence), but it is under-specified. It does not front-load key information about parameters or behavior. The brevity is not effective because it omits essential details that would help an agent use the tool correctly.

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 9 optional parameters, no output schema, and no annotations, the description is severely incomplete. It does not explain what the tool returns, what 'can be opened' means, or how to use the parameters. The lack of context makes it nearly impossible for an agent to know what inputs to provide 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 coverage is 100%, so each parameter has a description, but the tool description does not explain how these parameters relate to the URL check. The parameter descriptions themselves are somewhat informative (e.g., 'Git ref name; discarded after the shape check') but they seem to describe a different tool. The description adds no value beyond the schema and creates confusion due to the mismatch.

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 and resource: 'Check whether a URL can be opened.' It also adds a distinguishing note ('No browser is launched') that separates it from playwright-url-ok. However, the input schema includes many unrelated parameters (city, json, path, zone) that are not mentioned, creating ambiguity about the tool's actual scope.

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?

No guidance is provided on when to use this tool versus siblings like fetch-status or normalize-url. There are no exclusions, alternatives, or conditions. The description simply states what it does without contextualizing its place among the other URL-related tools.

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