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 does state one important trait: 'No disk access,' which clarifies that the check is non-invasive and does not verify existence or permissions. However, it says nothing about return values, error behavior, or what exactly 'safe' means, so the disclosure is 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?

The description is highly concise and front-loaded: the first sentence states the core purpose, and the second adds meaningful no-side-effect information. There is no filler or redundancy, though it is so terse that it sacrifices helpful detail.

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 nine optional parameters, no annotations, and no output schema, a seven-word description is not enough. It does not identify which parameter to pass, whether multiple parameters may be supplied, what 'safe' means, or what the tool returns. An agent would have difficulty invoking this correctly without extra information.

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 the baseline is 3 even without parameter details in the description. The description itself adds no parameter guidance, and the schema exposes eight additional unrelated-looking optional parameters, which could confuse an agent. But since each parameter already has a clear schema description, the description does not need to compensate.

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 ('Check') and resource ('a path'), and 'No disk access' signals that this is a purely syntactic or lexical safety check. However, 'looks safe' is ambiguous, and it does not explicitly differentiate this from sibling validators like browser-url-ok or normalize-url, so it misses the highest bar.

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?

There is no explicit guidance about when to use this tool or when to prefer an alternative. 'No disk access' weakly implies a pre-flight validation use case, but the description never says 'use before filesystem access' or 'use for paths only, not URLs,' leaving the agent to infer the intended context.

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