Create Mailbox Folder

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

Annotations already indicate idempotent and non-destructive write. Description adds context about avoiding duplicate sibling names, which is a useful behavioral hint. It does not contradict annotations and enhances transparency.

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?

Two sentences: first states purpose, second provides usage hint. No redundancy, front-loaded, and every sentence adds value.

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 the simple tool (4 params, 3 required, output schema exists), the description covers what the tool does, how to use it correctly (list folders first), and basic behavior. Combined with annotations, it is complete enough for the agent to invoke correctly.

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 parameters are well-documented there. The description adds minimal parameter-specific info beyond schema, but the mention of 'subfolder' and 'root folder' contextualizes parent_id usage. Baseline 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?

Description clearly states 'Create a custom folder or subfolder for a mailbox.' It specifies the action (create) and resource (custom folder/subfolder), and distinguishes from sibling tools like update and delete by suggesting use of shipmail_list_mailbox_folders.

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?

Explicitly tells when to use this tool (to create folder/subfolder) and provides direct guidance: 'Use shipmail_list_mailbox_folders first to choose a parent and avoid duplicate sibling names.' This helps the agent select the right tool and prepare.

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