list_mailboxes

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

With no annotations, the description carries the full burden. The verb 'List' implies read-only, but the description does not explicitly state safety, no side effects, or any behavioral expectations beyond the result set. However, the output schema covers return structure, and the operation is inherently safe, so a 3 is reasonable.

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?

A single, front-loaded sentence that states the action, target, and scope with zero wasted words. Every word earns its place.

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 simplicity of the tool, the description, along with a well-documented schema and an output schema, is nearly complete. The only slight gap is not mentioning that 'account' typically comes from list_accounts, but that is already embedded in the parameter description.

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% for the single parameter 'account', and the schema already provides a detailed explanation (display name vs UUID, stability). The tool description adds no extra parameter information, which is acceptable given high schema coverage.

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 ('List') and resource ('mailboxes') with a scope restriction ('for an account'). It clearly distinguishes from sibling tools like create_mailbox, update_mailbox, and delete_mailbox, and the 'all' modifier sets expectations about completeness.

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 implies usage (to get mailboxes for a given account) but does not explicitly mention alternatives or when to prefer this over list_accounts. It's clear enough for a simple list operation, but there is no explicit when/why guidance.

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