Copy Mail

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

With no annotations provided, the description carries the full burden. It discloses the required delegated Mail.ReadWrite permission, which is a critical behavioral trait. The verb 'copy' implies the original remains, but it does not explicitly mention side effects or reversibility. The auth disclosure is a valuable addition.

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 concise: one main sentence, one permission note, and Chinese intents. It is front-loaded with the action and contains no fluff or redundant information.

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 simple two-parameter tool with no output schema, the description covers the core action, the permission requirement, and language variations. It does not explain return values or edge cases, but these are not essential given the tool's simplicity.

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 has 100% coverage with descriptions for both messageId and destinationFolderId. The tool description does not add further meaning beyond what the schema already states, so the baseline of 3 is appropriate.

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 the exact action: 'Copy a message into another mailbox folder.' It uses a specific verb and resource, and the word 'copy' distinguishes it from sibling mail_move_message. The inclusion of Chinese intents also reinforces the purpose.

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 clearly implies when to use (when a message needs to be copied to another folder), but it does not explicitly contrast with mail_move_message or state when not to use. The permission requirement adds context, but no alternative tools are named.

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