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' but does not explain what the check actually does (network request? format validation?), what the return value is, or side effects. The schema hints at 'shape checks' and 'discarded after' notes, but these are not surfaced 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 extremely short (one sentence), but conciseness should mean appropriately sized for the tool's complexity. With 9 parameters and no annotations, this is under-specification, not efficient brevity. It omits essential information about the tool's actual scope and behavior.

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 description is completely inadequate for a tool with 9 parameters, no output schema, and no annotations. An agent has no idea what the tool does beyond a vague URL check, cannot map the parameters to behavior, and lacks any return format. It is far from complete.

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 description mentions no parameters. While the schema covers all 9 parameters with descriptions (100% coverage), the description adds no value in linking them to the tool's purpose. The mismatch between the URL-focused description and the diverse parameter list actually confuses rather than clarifies parameter usage.

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 verb and resource ('Check whether a URL can be opened'), but the schema reveals nine parameters covering city, JSON, timezone, file paths, etc., which contradicts the narrow URL-only focus. The purpose is ambiguous and potentially misleading; it does not clearly differentiate from siblings like browser-url-ok or fetch-status.

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 given on when to use this tool versus alternatives. The only behavioral hint, 'No browser is launched,' is buried in the description and does not explain selection criteria. Sibling tools such as browser-url-ok or fetch-status are not mentioned.

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