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

Annotations already mark the tool as mutating, non-destructive, and idempotent. The description adds a genuine behavioral fact not visible in the schema: missing parent folders are created automatically. It stops short of explaining failure modes or existing-folder behavior, but the idempotent annotation covers that concern.

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?

One sentence, no filler, and the key behavioral nuance (parent folders) is included immediately. Every word earns its place.

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 two-parameter creation tool with rich annotations and an output schema, the description is nearly sufficient. The only mild gap is not spelling out what happens when the target directory already exists, though the idempotentHint implies a benign repeated call.

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 100%, so the schema itself documents path and site meanings with examples. The description adds no parameter-level detail, which is acceptable because the schema carries the full burden.

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 names a concrete action ('Creates a folder') and a specific resource, and adds recursive-parent behavior. This clearly separates it from siblings like write_file and move_path, which describe different path operations.

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 purpose strongly implies use when a directory is needed, but the description gives no explicit when-to-use guidance, exclusions, or comparisons with sibling tools. An agent must infer the appropriate context from the verb and resource.

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