create_directory

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

The description discloses that it 'only works within allowed directories' and explains path normalization and potential issues with relative paths. The annotations indicate a non-read-only, non-destructive operation, and the description adds useful behavioral context without contradiction.

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 somewhat verbose with multiple paragraphs and code formatting. While it front-loads the purpose, it could be more concise. Some details (e.g., referencing instructions) add length without critical 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 tool with one parameter and no output schema, the description adequately covers what the tool does and how to use it. It provides enough context for the agent to succeed, though it could briefly mention expected return values.

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 one parameter 'path' with no description (0% coverage). The description fully compensates by explaining the meaning of the path, when to use absolute vs relative, and normalization behavior.

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 action: 'Create a new directory or ensure a directory exists.' It also mentions the capability to create multiple nested directories, which distinguishes it from other file operations like 'write_file' or 'edit_block'.

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 on using absolute paths, warns about relative and tilde paths, and mentions path normalization. It also suggests how to reference the command in instructions. However, it does not explicitly contrast with when to use alternative tools.

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