create_directory

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It transparently reveals idempotent behavior ('If the directory already exists, this operation will succeed silently'), supports nested directory creation, and states the allowed-directory restriction. It does not cover edge cases like invalid paths or permission failures, but for a mkdir-style tool, this is substantial transparency.

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 concise, using three sentences that front-load the main action and follow with important behavioral details. No redundant information is present; every sentence adds value, from the basic function to the idempotency and the allowed-directory constraint.

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?

Given the tool's simplicity (one parameter, no output schema, no annotations), the description is quite complete. It covers the core action, the nested-directory capability, the silent success for existing directories, and the access restriction. An agent can confidently invoke the tool based on this description alone.

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 input schema provides only a 'path' property with no description, and schema description coverage is 0%. The description partially compensates by implying that 'path' can include multiple nested levels ('Can create multiple nested directories in one operation') and must be within allowed directories. However, it does not explicitly explain path format (absolute vs relative) or the exact nature of the path parameter, leaving some ambiguity for a single-parameter tool.

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 tool's function with the verb 'create' and resource 'directory', and adds the crucial nuance of 'ensure a directory exists' (idempotency). It distinguishes itself from sibling tools like write_file or delete_file by focusing on directory creation, including the ability to create nested directories.

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 description provides explicit use cases: 'Perfect for setting up directory structures for projects or ensuring required paths exist.' It also includes a constraint ('Only works within allowed directories') that implicitly guides the agent to check list_allowed_directories. However, it does not explicitly mention when not to use the tool or compare it with alternatives.

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