fs_list_dir

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

With no annotations, the description must carry the behavioral burden, and it does state the key behavior: listing only direct children and treating an empty glob as 'list everything.' It does not disclose details such as hidden-file inclusion, ordering, or error handling, but these are relatively minor for a read-only listing tool.

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 front-loaded summary sentence plus two terse, informative argument bullets. No filler, no repeated schema title, and every sentence adds value.

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 two-parameter listing tool with an output schema present, the description provides enough invocation information: path, optional filter, and non-recursive scope. It omits minor details like whether directories themselves are included or how hidden files are treated, but these do not block 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%, so the description is the only source of parameter meaning. It explains both parameters clearly: path is 'the directory to list' and glob is an optional shell-style pattern with an explicit empty-default behavior and a concrete example ('*.pdf').

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 opens with a specific imperative: 'List entries directly under a directory,' identifying both the operation and the resource. The phrase 'directly under' clarifies that this is a non-recursive, immediate-child listing, which helps separate it from search and read tools, though it never explicitly names or contrasts a sibling.

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?

Usage is implied by the summary and arguments: call it when you need the immediate children of a path, optionally filtered by a glob. There is no explicit guidance about when to choose fs_search, fs_read, or fs_stat instead, and no 'do not use when' exclusions.

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