folders

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so 'Changes nothing' mostly reinforces them. The description adds genuine behavioral context the annotations lack: restricted mailboxes return an error that names the allowed mailboxes, and special folders are marked. Missing rate-limit/pagination notes keeps it from a 5.

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?

Four short sentences, front-loaded with what it returns and scoped precisely; the alternative and error behavior come after. Tight, though 'Changes nothing' is mildly redundant with the readOnly annotation.

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?

An output schema exists so return values need no explanation, and the description covers the remaining agent-relevant concerns: folder-name consumption by other tools, the accounts alternative, and the restricted-mailbox error path. Nothing needed to call it correctly is missing.

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%, so both parameters (sizes, account) are fully documented in the schema itself. The description's mention of counts and special folders doesn't add syntax or meaning beyond what the schema already provides, so baseline 3 applies.

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?

States a specific verb (List), resource (folders), scope (one mailbox), and the payload (message and unread counts, special-folder marking). It also distinguishes itself from siblings by noting accounts lists mailboxes and that emails/search/action consume folder names.

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?

Explicitly says to use this tool to obtain the exact folder names that emails, search (scope) and action (moveToFolder) require, and names accounts as the alternative for listing mailboxes. When-to-use and the sibling boundary are both stated.

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