List Allowed Directories

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

The description adds that subdirectories within allowed directories are also accessible, which is not covered by annotations (readOnlyHint, openWorldHint). This provides useful context beyond the structured fields. No contradictions.

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 sentences, each earning its place: first states the purpose, second provides usage guidance. No redundant or unnecessary words. Front-loaded with the key action.

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 zero-parameter tool with an output schema, the description is complete. It explains what is returned, that subdirectories are included, and when to use it. No gaps given the tool's simplicity and the presence of an output schema.

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 tool has zero parameters, so schema coverage is complete. Baseline for 0 params is 4. The description indirectly explains the output (list of directories), but since there are no parameters, no additional semantics are needed.

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 ('Returns the list') and resource ('directories'), clearly distinguishing it from siblings like list_directory which list contents of a directory. It unambiguously states what the tool does.

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 explicit guidance: 'Use this to understand which directories and their nested paths are available before trying to access files.' It tells the agent when to use the tool, though it doesn't explicitly mention when not to use it or alternatives. For a simple zero-parameter tool, this is sufficient.

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