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

With no annotations provided, the description carries the full burden and does well: it discloses visibility to every mailbox holder in webmail and mail clients, plus naming constraints such as forbidden characters, neighbor uniqueness, and exclusion of default top-level names. It omits error behavior, permission requirements, and return details, but covers the key side effects and restrictions for a create mutation.

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 front-loaded with the core action and then adds visibility and naming rules in compact sentences. Every sentence contributes useful information, though the final clause about the six default mailbox folders is slightly dense and requires interpretation.

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 three-parameter create tool with full schema coverage, no output schema, and no annotations, the description supplies the important behavioral context: visibility, naming constraints, and placement. It does not cover return values or failure modes, but the essential information needed to call the tool correctly is present.

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 the baseline is 3, but the description adds meaningful validation for the name parameter beyond the schema's 200-character limit: no "/", "*", or "%", uniqueness among neighbors, and top-level default-name restrictions. It also reinforces that parent_id controls whether the folder is top-level or nested.

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 states a specific verb and resource: "Makes a folder in a mailbox," and clarifies placement at the top or under another folder. It does not explicitly distinguish this create operation from siblings like update_folder, delete_folder, or list_folders, so it stops short of a 5.

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 phrase "to file threads in" implies the intended use, and the placement options are clear. However, there is no explicit guidance on when to choose this tool versus update_folder, delete_folder, or list_folders, and no prerequisites such as required permissions are stated in the description.

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