mkdir

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

With no annotations provided, the description carries full burden. It discloses default parent directory creation, permission mode support on Unix/Linux, and dry-run capability. However, it does not mention behavior when directory exists, potential side effects, or error handling, leaving gaps.

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 consists of three concise sentences, each providing essential information. It avoids redundancy and is well-structured for quick comprehension.

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 tool with five parameters and no output schema, the description covers the main functional aspects: purpose, default behavior, mode, and dry-run. It omits details on return value and error conditions, but remains fairly complete given the tool's simplicity.

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 has 100% coverage with parameter descriptions. The description adds value by explaining the default recursive behavior ('Creates parent directories by default'), the scope of mode ('applied on Unix/Linux'), and the purpose of dry_run ('preview'). This goes beyond the schema descriptions.

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 'Create a directory' and specifies the resource (directory). It also distinguishes itself by noting it creates parent directories by default, which is a key behavioral feature. No sibling tool duplicates this purpose.

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 does not explicitly state when to use this tool versus alternatives, such as 'bash' for shell-based directory creation. It implies usage for directory creation but lacks guidance on when not to use it or related tools.

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