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

The description only discloses that 'No browser is launched,' which is minimal. It fails to mention that most parameters are discarded after validation, how results are returned, or any error/edge-case behavior. With no annotations provided, the description carries the full burden but does not satisfy it.

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 very short (two sentences) but this is under-specification, not conciseness. It omits essential information about the tool's scope, parameters, and behavior, so it fails to serve its purpose despite being brief.

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 severely incomplete. It does not explain why the extra parameters exist, what the tool returns, or how an agent should construct a call. The lack of any behavioral or parameter context makes the tool nearly unusable for correct selection and invocation.

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 description coverage is 100%, so each parameter is documented in the schema. However, the tool description does not connect these parameters to the stated purpose; the parameter descriptions themselves (e.g., 'discarded after the shape check') suggest a broader shape-checking function that the main description contradicts. The description adds no value beyond the schema and actually creates confusion.

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 accepts nine unrelated parameters (ref, city, json, path, zone, query, etc.) that have nothing to do with URL checking. This mismatch makes the tool's actual purpose ambiguous and could mislead an agent into thinking it only handles URLs when it likely performs a broader shape-checking role.

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 vs. alternatives like normalize-url, fetch-status, or web-fetch. There is no mention of prerequisites, exclusions, or scenarios where a sibling tool would be more appropriate.

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