fs_list_directory

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

No annotations are provided, so the description carries full burden for behavioral disclosure. It merely says 'Scan directory' without stating whether this is read-only, how recursion works, what 'only_files' does, or what error conditions might occur. The behavioral traits are mostly left to the parameter names, which is insufficient.

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 short sentence, making it concise in word count. However, it lacks any structure that would help an agent parse options or prerequisites. It is under-specified, which reduces the value of its brevity.

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?

With four parameters, a matching filter, and a recursive option, the description is far too thin. It doesn't explain how matching works, what values are acceptable for source_dir, or how recursive and only_files interact. Although an output schema exists, the description still fails to provide sufficient context for correct 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 0%, and the description does not explain any of the four parameters. 'Scan directory' implies source_dir, but recursive, only_files, and file_extension are not described. The parameter names provide some hints, but the description adds no additional semantic value beyond simple inference.

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 ('Scan') and resource ('directory') and states the result ('matched absolute path list'). It clearly distinguishes from sibling file-operation tools, as this is the only directory listing tool. However, 'matched' is ambiguous—it doesn't specify what matching criteria apply (e.g., file extension), so it's not a perfect 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?

The description provides no guidance on when to use this tool versus alternatives. It doesn't mention when to choose it over the search tools (e.g., fs_search_files_by_content) or how to combine it with other directory operations. No exclusions or alternative suggestions are given.

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