imap_list_folders

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

With no annotations, the description carries the behavioral disclosure burden. It reveals what the response contains and explains how to interpret the specialUse field, including the localized-name example ('Gesendet' is Sent when specialUse is '\Sent'). It does not explicitly claim read-only safety, but the read-only nature is strongly implied by 'List'.

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 sentences, each earning its place: the first states the purpose and payload, the second gives the temporal use-case, and the third adds the specialUse mapping that prevents misinterpretation of localized folder names. The most critical information is front-loaded.

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 zero-required-parameter list tool with no output schema, the description covers the important return fields, the discovery use case, and the provider-variation rationale. It leaves minor ambiguity about whether all hierarchy levels are returned in a flat list or nested, but the hierarchy-delimiter mention partly addresses this.

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?

The input schema already provides 100% coverage of both optional parameters (accountId, accountName) with clear descriptions. The tool description adds no additional parameter-level meaning beyond the schema, so it stays at the baseline.

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 action ('List all folders/mailboxes') and the exact resource scope ('for an account'), then enumerates the returned data (names, hierarchy delimiter, attributes, special-use role). The emphasis on using it before search/move/create operations distinguishes it from sibling tools that operate on specific folders.

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 frames the tool as a discovery step: 'Use this first to discover exact folder names before searching, moving, or creating subfolders.' It also explains why (folder naming varies by provider) but does not state when not to use it or name alternative tools like imap_folder_status.

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