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

Annotations provide only readOnlyHint=false, idempotentHint=false, and destructiveHint=false, which carry limited behavioral weight. The description adds the key nested-folder behavior, but does not mention failure modes such as duplicate folder names, missing parent folders, or permission requirements.

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 a single sentence with no filler: verb, resource, and scope are front-loaded. Every part earns its place for this simple tool.

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 tool with one required parameter and full schema coverage, the description plus schema provide enough to invoke it correctly. It could optionally mention return values or duplicate-name behavior, but those are minor omissions for such a straightforward operation.

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%: both 'name' and 'parent_id' already have clear descriptions. The tool description adds only a plain-language restatement of nesting behavior without new constraints or syntax, so it falls at the baseline for fully covered schemas.

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 uses a specific verb ('Create') and resource ('folder'), and adds useful scope: 'at the top level or inside another one.' This clearly separates mkdir from filesystem siblings like rmdir, ls, and mv, and from unrelated app-level tools.

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 makes the primary use case clear—creating a folder, either at the top level or nested—and implicitly explains when parent_id should be provided versus omitted. It does not explicitly name alternatives or when not to use the tool, but no sibling tool directly competes with this action.

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