List mailboxes

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful output context (unread counts, special-use flags), but says nothing about ordering, pagination, or what happens for accounts with no mailboxes.

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 short sentences with zero filler; the capability statement leads and the prerequisite follows. Every clause 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?

With an output schema present, return-value detail is handled elsewhere, and annotations cover the read-only nature. The prerequisite to call list_accounts closes the main gap; only edge cases like empty accounts or result ordering are unaddressed.

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 'account' parameter, so the schema already documents it. The description only reinforces provenance ('from list_accounts'), adding little beyond the schema's own wording.

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?

Specific verb+resource (list mailbox folders) scoped to a single account, and it names what the result carries: unread counts and special-use flags. That distinguishes it from sibling listers like list_accounts and list_labels, though it does not explicitly contrast itself with create_mailbox/rename_mailbox beyond the obvious naming.

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?

It gives an explicit prerequisite ordering: 'Use list_accounts first to get the account name,' which tells the agent the required call sequence. It stops short of stating when-not to use it or naming alternative folder-inspection tools such as find_email_folder.

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