mail_folders

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the description earns credit for going further: it discloses no message bodies are read and, importantly, the 64 KiB overflow behavior where full results go to a private JSON file and a compact summary with completeResultFile is returned. That overflow contract is behavioral detail an agent cannot get from annotations alone.

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?

Three short sentences with zero filler; the scope enumeration comes first and the overflow/return-format detail follows. Every sentence carries distinct information.

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 no output schema and no parameter documentation, the description does well to describe the result shape (folders, roles, status counts, completeResultFile path) and the no-body-read guarantee. The only meaningful omission is any explanation of the accountId input.

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?

There is one required parameter (accountId) and schema description coverage is 0%, so the schema provides no semantic help. The description never mentions accountId at all, so it fails to compensate — the agent gets no hint about what identifies an account or where to obtain that value.

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 ('List') plus resource ('every mailbox folder') with explicit scope: unsubscribed folders, special-use roles, and server status counts. This clearly separates it from siblings like mail_list_messages and mail_manage_folder, which operate on messages or folder mutation.

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?

Usage is implied — an agent enumerates folders before acting on them — but the description never states when to prefer this over mail_manage_folder or mail_accounts, nor any precondition such as needing a resolved accountId. Adequate but with a clear gap.

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