Create Directory

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

The description goes beyond the idempotentHint annotation by stating that existing directories will cause the operation to 'succeed silently' and that multiple nested directories can be created at once. It also discloses the permissions boundary via 'Only works within allowed directories.' 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 description is compact and front-loaded, covering the core action, idempotency, nested behavior, use case, and a security constraint in only four sentences. 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 simple one-parameter tool, the description sufficiently covers the behavior, constraints, and use case. The main remaining gap is precise path-format guidance, but the existence of list_allowed_directories as a sibling and the output schema fill in much of the missing context.

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 must compensate. It does partially: 'Can create multiple nested directories in one operation' clarifies that `path` can contain multiple segments, and 'Only works within allowed directories' constrains its values. However, it does not specify path format (e.g., relative vs absolute, trailing slash) or how allowed directories are determined.

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 clearly states the verb and resource ('Create a new directory or ensure a directory exists') and adds meaningful detail about nested creation. It is easily distinguished from sibling file-read/write tools because it explicitly targets directory creation.

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?

It gives practical usage context ('Perfect for setting up directory structures...') and an important constraint ('Only works within allowed directories'). It does not explicitly name alternatives or conditions to avoid, but the use case is clear enough for an agent to decide when to call it.

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