文件元数据

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

The readOnlyHint annotation already establishes that this operation does not mutate state. The description adds that the tool returns type/size/mtime/permissions, which is useful context but does not disclose behavior for missing paths, symlinks, or error cases. With annotations covering the safety profile, a 3 is appropriate.

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?

One concise sentence that front-loads the verb and lists the returned metadata fields without redundant words. Every part contributes directly to the tool's purpose.

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 one-parameter, read-only metadata tool with no output schema, the description covers the essential return fields and accepts both files and directories. Missing edge-case behavior (nonexistent path, permission errors) is minor given the low complexity and readOnlyHint annotation.

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 provides only a required string 'path' with zero description coverage. The description partially compensates by indicating the path may refer to a file or directory, but it does not specify path format, relative/absolute requirements, or examples. Baseline 3 is justified because the single parameter is self-explanatory and the description adds some meaning.

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 uses a specific verb ('返回') and names the resource (文件或目录) plus the exact fields returned (类型、大小、修改时间和权限), making the purpose clear. It does not explicitly differentiate itself from sibling tools like read_file or list_directory, so it falls short of a 5.

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 guidance about when to choose file_metadata over siblings such as find_files, list_directory, or read_file. The description implies a metadata use case but provides no exclusions or alternative routing, leaving the decision to inference.

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