list_mail_folders

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

Annotations already cover readOnly, idempotent, openWorld and non-destructive, so the safety profile is free. The description adds genuinely new behavior: results are paginated, canonical folder names are preserved, and Outlook accounts are out of scope. It stops short of describing ordering or page-size defaults.

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 terse fragments, front-loaded with the core purpose and scope, with zero filler. The telegraphic style ('no Outlook account') is efficient but slightly clipped rather than fully formed.

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 two-parameter read-only list tool with no output schema, the description covers scope, pagination and naming but omits the pagination contract (page size, offset semantics) and says nothing about what a returned folder record looks like. Adequate but with visible gaps.

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% for the two parameters (limit, offset). 'Paginated' gestures at them but supplies no meaning: no default page size, no note on how offset interacts with ordering, and no hint that both are optional. For a low-coverage schema the description should carry more of this burden.

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/discover) and resource (personal iCloud mail folders), and scopes it to 'permitted personal iCloud' rather than all folders. It is distinguishable from siblings like search_messages or fetch_message, though it never names an alternative to route against.

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?

'Discover permitted personal iCloud folders' implies when to reach for it, and 'no Outlook account' provides one explicit exclusion. However, there is no positive guidance on when to prefer this over sibling tools, so usage is only implied.

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