list_mailboxes

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

With no annotations, the description carries full burden. It discloses key behaviors: optional filtering by account, togglable message counts, and return format (indented/path for nested). It does not specify if it is read-only, but the verb 'list' implies idempotence.

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 concise (9 lines) and well-structured: purpose first, then parameter details, then return format. Every sentence adds value with no redundancy or tangents.

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 listing tool with two optional parameters and an existing output schema, the description covers the essentials. It explains return format details that supplement the output schema, making it fully complete for an agent.

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 the description compensates well. It explains the 'account' parameter as optional with example values ('Gmail', 'Work'), and 'include_counts' with default True. It adds meaning beyond the bare 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 the tool lists mailboxes (folders) for accounts, with optional filtering. It uses specific verbs and resources, and differentiates from siblings like list_accounts or list_inbox_emails by focusing on folder-level listing.

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 for listing folders but does not explicitly state when to use this tool versus alternatives, nor does it provide when-not-to-use or exclusion criteria. It lacks guidance on selection among sibling tools.

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