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

With no annotations provided, the description carries the full burden of behavioral disclosure. It discloses one key non-obvious behavior: parent directories are created automatically. However, it does not mention security/permissions, what happens if the directory already exists, or whether the operation is reversible. This is useful but incomplete.

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 two sentences long, front-loaded with the primary purpose and a key behavioral detail. Every word earns its place, with no fluff or repetition of schema information. It is extremely concise and well-structured.

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 two parameters and no output schema, the description is adequate. It covers the core action and the most important behavioral nuance (auto-creation of parents). Some additional details about error handling or return values could improve completeness, but overall it is sufficient for a tool of this 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 schema already provides descriptions for both parameters (app and path) with 100% coverage, so there is a solid baseline. The description goes beyond the schema by explaining that parent directories are created automatically, which directly impacts how the 'path' parameter should be interpreted (e.g., nested paths are supported).

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 directory') and the scope ('in an app'), using a specific verb and resource. It distinguishes from sibling tools like create_app or write_file by focusing on directory creation. The additional note about parent directories being created automatically adds further specificity about the tool's behavior.

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 clear context for when to use the tool: when you need to create a directory within an app. It implies that the tool handles nested paths automatically. However, it does not explicitly mention any alternatives or when not to use it, so it falls short of a full 5 but is still strongly contextual.

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