create_folder

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

Beyond the annotations (readOnly=false, idempotent=false, destructive=false), the description adds substantial behavioral context: required Mail.ReadWrite permission, OUTLOOK_READONLY restriction, duplicate folder behavior (409 error, no double creation), parent must exist, no automatic intermediate folder creation, and no effect on existing emails. It also confirms these behaviors are verified on a real device. No contradiction with annotations.

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?

Though the description is relatively long, every sentence earns its place. It opens with a one-line summary, then follows with usage focus, behavior bullet points, permission note, and parameter details. The bullet-point structure improves scannability, and there is no fluff or redundancy. The length is justified by the tool's complexity and the edge cases documented.

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?

The description is complete given the tool's complexity and the presence of an output schema. It covers prerequisites (permission, existing parent), failure modes (409 on duplicate, missing parent), usage sequence (call before moves), and parameter constraints. The output schema presumably describes the return value, so no need to duplicate that. It leaves no significant gaps for an agent to misuse the tool.

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 provides only type/title/default for 'name' and 'parent' with no descriptions. The description's Args section adds rich semantics: 'name' cannot contain '/' and must be unique under the same parent; 'parent' can be a folder name or full path, is optional, and must point to an existing folder. This fully compensates for the 0% schema description coverage.

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 the tool's function: 'Create one empty folder. Does not move emails.' It specifies the resource (folder), action (create), and scope (empty, no email movement). It also differentiates from sibling tools by explicitly referencing move_folder/rename_folder and move_messages/move_by_search, making its purpose unambiguous.

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 gives explicit guidance on when to use this tool: call it first when needing a destination for emails, since move_messages and move_by_search cannot move to nonexistent folders. It also states when not to use it: use move_folder or rename_folder instead if only moving or renaming an existing folder. This covers both when and when-not with named alternatives.

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