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

With no annotations, the description carries full burden. It only adds 'No browser is launched,' but does not disclose what the tool actually does (e.g., makes an HTTP request, checks DNS, returns a boolean), what parameters affect the check, or any side effects. Minimal and incomplete.

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?

Two sentences with zero waste, but it is under-specified for a tool with 9 parameters. The concise style is appropriate in length but lacks critical information, making it insufficient rather than appropriately sized.

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 drastically incomplete. It does not explain the role of the parameters, the meaning of 'can be opened,' or the return value, leaving the agent unable to use the tool 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 parameters are individually described, but the tool description adds no clarification on how the parameters relate to URL checking. The parameter descriptions themselves seem mismatched (city, json, path, zone), and the description does not resolve this confusion, offering no added meaning beyond 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?

States a clear verb and resource ('Check whether a URL can be opened') but does not specify what 'can be opened' means (HTTP status, reachability, validity). The 9 unrelated parameters (city, json, path, zone) confuse the purpose, and the description does not differentiate from siblings like 'playwright-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 on when to use this tool versus alternatives. The description does not mention context, prerequisites, or exclusions, leaving the agent to guess which sibling fits.

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