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

With no annotations, the description itself must disclose behavioral traits. It usefully states that the tool never touches the disk, making it side-effect-free and safe to invoke. It does not, however, describe what 'safe' means, whether it returns a boolean or result object, or how invalid input is handled.

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 and front-loaded. Both sentences earn their place: the first names the action and resource, the second adds an important side-effect disclosure. No filler or redundant wording.

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 tool has neither annotations nor an output schema, so the description must be self-sufficient. It fails to explain the return value, define 'safe', or account for the six non-path input fields shown in the schema. An agent may not know which parameters are relevant or what result 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?

The input schema already describes all seven fields in detail, so the baseline is 3. The description adds no parameter-level meaning and does not clarify why non-path fields like city, feed, or json exist or whether only 'path' is used. Schema coverage itself carries the semantic load.

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 names the exact operation ('check') and resource ('a path'), and adds 'looks safe' to indicate a heuristic/shape validation. 'No disk access' helps separate it from filesystem-touching operations. However, 'safe' is left undefined, so the precise hazard being checked is still unclear.

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 statement of when to use this tool versus sibling shape-checkers such as browser-url-ok or domain-shape. 'No disk access' implies it is a lightweight pre-check before file operations, but that is an inference rather than clear guidance.

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