list_mail_folders

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

With no annotations, the description carries the full burden of disclosing behavior. It accurately describes the scoping behavior (all vs. child folders) but does not mention potential limitations like pagination, sorting, or the exact return structure. The read-only nature is implied by the word 'list' but not explicitly stated.

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?

The description is a single, well-structured sentence that front-loads the action and resource. It contains no filler or redundant information, making it highly concise.

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?

Given the simple nature of the tool (one optional parameter, no output schema), the description sufficiently covers its core purpose and behavior. The absence of an output schema means return values are not described, but the tool name and typical usage make the return type (a list of folders) fairly obvious. Minor gaps around pagination or details of returned folder objects are acceptable for a listing operation.

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 schema already provides a 100% description for the only parameter (parentFolderId), so the description adds no extra detail about the parameter itself. It only reiterates the child-folder behavior already captured in the schema, keeping the baseline score at 3.

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?

The description clearly states it lists all mail folders or child folders of a specific folder, using a specific verb ('list') and resource ('mail folders'). It distinguishes itself from sibling email/calendar tools by focusing solely on folder management.

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?

The description implies when to use the tool: for exploring folder hierarchies. It clearly defines two modes (top-level or child folders) but does not explicitly mention when not to use it or name alternative tools. The absence of exclusions is acceptable for a straightforward listing tool.

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