is_dir

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 states the core behavior but does not specify behavior for nonexistent paths, error handling, or whether symbolic links are followed. The description is clear but lacks edge-case context.

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 a single, concise sentence with no unnecessary words or repetition. It is front-loaded and directly states the tool's function.

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 simple predicate tool with an output schema, the description is adequate but not fully complete. It lacks edge-case behavior (e.g., nonexistent paths) and does not clarify when to use this tool over 'exists' or 'get_file_info'. The description would benefit from stating the exact return behavior and error conditions.

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 0%, so the description must compensate. It only mentions 'path' without adding details about format (absolute/relative, URL-encoding), required conventions, or how invalid paths are handled. The description provides minimal extra meaning beyond the parameter name.

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 '判断坚果云路径是否为目录' clearly states the tool's purpose: to determine whether a given Jianguoyun path is a directory. It uses a specific verb and resource, and it distinguishes itself from sibling tools like 'exists' (which checks only existence) and 'get_file_info' (which retrieves details).

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?

The description implies usage when you need to know if a path is a directory, but it provides no explicit when-to-use guidance or alternatives. There are no exclusions or comparisons to sibling tools such as 'exists' or 'get_file_info', so the user must infer the appropriate context.

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