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

Annotations already declare this is a safe, read-only, non-destructive, non-open-world operation, so the bar is lower. The description still adds real behavioral value by disclosing the depth-first output ordering and the per-subfolder cap of 100 entries, which an agent cannot infer from annotations or schema.

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?

Two compact sentences with zero filler; the output format is stated first and the depth semantics follow, so the most decision-relevant information is front-loaded.

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 no output schema, the description usefully covers the return format and the 100-entry truncation, which is the main completeness risk. Minor gaps remain on the path default and on what depths 0 and 3-5 actually do.

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 only 50% (path and depth are undocumented in the schema), yet the description fully explains depth: default 2, depth 1 meaning, and recursion semantics. The path parameter's "~" default and depth values 0 or 3-5 remain unexplained, so it stops short of a 5.

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?

States a specific verb ("List") and resource ("a folder") and even pins down the output line format with [DIR]/[FILE] prefixes. It does not explicitly differentiate itself from siblings like search_files or stat_path, which keeps it just 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?

The depth explanation gives implicit guidance on how to scope a listing (shallow vs. recursive), but there is no explicit when-to-use/when-not-to-use statement or pointer to an alternative such as search_files for content-based discovery.

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