copy-mail-message

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

Describes return value (newly created message with new id) and body format. Annotations already indicate write operation, so description adds useful context beyond 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?

Concise, front-loaded with action, uses bullet/tip format effectively. No unnecessary words.

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?

Covers key aspects: action, parameters, return value, comparison to sibling. Could include more details on return type but sufficient given no output schema.

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?

Adds significant value over schema: explains DestinationId format with examples (inbox, archive, junkemail), clarifies messageId parameter naming and origin, and mentions optional parameters.

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?

Clearly states it copies a message to a folder, specifies destination via DestinationId, and distinguishes from move-mail-message.

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 contrasts with move-mail-message: 'For moving instead of copying, use move-mail-message.' Provides tip on usage.

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