create_mailbox

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

The annotations already convey that this is a non-read-only, non-destructive, idempotent operation. The description adds no behavioral detail beyond the obvious creation action—such as duplicate handling, naming constraints, or account-specific behavior—so it provides little value beyond the structured annotations.

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 concise sentence with no wasted words, and the core action is front-loaded. While very brief, it earns its place as a clear minimally sufficient summary.

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 creation tool, the combination of schema, annotations, and output schema covers the essential invocation details. The description doesn't need to explain return values or parameter semantics because those are already present in structured fields. It would only be incomplete if behavioral edge cases were not covered, but annotations compensate here.

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%, and the schema already thoroughly documents the 'name', 'account', and 'parent_mailbox' parameters, including UUID stability and nesting semantics. The description itself adds no parameter-level meaning, so the baseline score of 3 is appropriate.

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 a clear resource ('mailbox/folder'), making the tool's purpose immediately understandable. It is naturally distinguished from sibling tools like list_mailboxes, update_mailbox, and delete_mailbox by the action it performs.

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 explicit when-to-use guidance or mention of alternatives, but the action 'Create a new mailbox/folder' implicitly conveys that this tool is for creating mailboxes. It does not discuss when not to use it or contrast it with update_mailbox/delete_mailbox.

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