create_mailbox

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

With no annotations, the description carries the full burden of behavioral disclosure. It only states the action with no mention of side effects, permission requirements, what happens on duplicate names, or whether the operation is reversible. The description is so minimal that an agent cannot predict consequences beyond the immediate creation.

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, succinct sentence with no wasted words. It is front-loaded with the core action and resource. It could be slightly more structured (e.g., adding a brief note about nesting), but it is appropriately concise for a simple create operation.

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?

The tool is a basic create operation, and the output schema exists, so return values need not be described. However, given the lack of annotations, the description is incomplete in conveying behavioral nuances (e.g., whether parent_mailbox nesting has any special requirements). It is adequate for a simple tool but leaves room for more context.

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 parameters are fully documented in the schema itself. The description adds no additional parameter semantics beyond what the schema already provides. Per the rubric, this warrants a baseline of 3.

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') and the resource ('a new mailbox/folder'), making the tool's purpose immediately understandable. It is specific enough to distinguish from update/delete/list siblings, though it does not explicitly differentiate from other creation tools like create_rule, which is acceptable given the distinct resource.

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?

There is no guidance on when to use this tool versus alternatives. While it is the only create-mailbox tool, the description does not mention prerequisites (e.g., an existing account), when nesting is appropriate, or any conditions that would favor this over updating or deleting a mailbox. The schema covers structure but not usage context.

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