list_mailboxes

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

No annotations are provided, so the description carries full burden. It discloses the return format (formatted list with optional counts and nested path format), which is sufficient for a read-only listing tool. No behavioral contradictions.

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 mostly clear but includes an unrelated 'User Preferences' line that wastes space and adds no value for tool selection. The Args and Returns sections are well-structured, but the extra line reduces conciseness.

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 only 2 optional parameters and an output schema, the description covers purpose, parameters, and return format adequately. No missing information for effective tool invocation.

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 0%, so description must compensate. It explains both parameters with examples (e.g., 'Gmail', 'Work') and default values, adding meaning beyond the raw schema.

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 it lists all mailboxes/folders for a specific account or all accounts, with a specific verb 'list' and resource 'mailboxes'. It distinguishes from sibling tools like list_inbox_emails (which lists emails) and others.

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 provides clear context on when to use: to list mailboxes, optionally filtered by account. It does not explicitly state when not to use or name alternatives, but the purpose is unambiguous given sibling tool names.

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