List Directory

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

Beyond the readOnlyHint, the description discloses that listings are prefixed with [FILE]/[DIR] and that the operation only works within allowed directories, which are useful behavioral constraints. No contradiction with annotations.

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 first two sentences are tight and informative, and the allowed-directories warning matters. The sentence 'This tool is essential...' is promotional redundancy that adds no operational information.

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 single-parameter, read-only tool with an output schema and readOnly annotation, the description covers listing behavior, output presentation, and access scope. The main residual gaps are detailed path format and sibling routing, which are not critical for basic 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?

The path property's schema has no description, but the description clarifies that path is a directory location and restricts it to allowed directories. It still omits concrete format requirements such as absolute vs relative paths or existence requirements, so compensation for 0% schema coverage is partial.

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 concrete operation: get a detailed listing for a specified path, and even describes output prefixes. However, it does not explicitly distinguish itself from siblings like list_directory_with_sizes or directory_tree, so the agent must infer scope from the tool name.

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?

Provides only a generic use case ('understanding directory structure and finding specific files') and a restriction to allowed directories. It never says when to prefer this over list_directory_with_sizes or directory_tree, nor when not to use it.

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