create_mailbox

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

The description explains nesting behavior (e.g., 'creates each segment if needed') and the optional parent_mailbox parameter. It mentions return confirmation. However, it omits potential constraints like account existence, name uniqueness, or required permissions. The user preferences line seems extraneous but not harmful.

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 front-loaded with the purpose and includes concise parameter descriptions. However, the 'User Preferences' line appears irrelevant and adds clutter. It could be trimmed without losing clarity.

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?

Given an output schema exists and the description mentions 'Confirmation with the new mailbox path,' the tool is adequately documented for a simple creation action. Missing details like idempotency or error handling (e.g., if mailbox already exists) would improve completeness but are not critical.

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?

With 0% schema description coverage, the description adds significant value: it explains that name can contain '/' for nested paths, parent_mailbox is optional, and account gives examples. It does not list allowed values or constraints for account, but the examples are helpful.

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 'Create a new mailbox (folder) in the specified account,' which is a specific verb+resource. It distinguishes from sibling tools like list_mailboxes or get_unread_count that serve different purposes.

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 explains two distinct usage patterns (using parent_mailbox for nesting or passing a full slash-separated path). It does not explicitly state when not to use this tool versus alternatives, but given that no sibling tool creates mailboxes, the context is clear enough.

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