copy-mail-message

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

Annotations already indicate destructiveHint=true and readOnlyHint=false, so the mutable nature is clear. The description adds that it returns the newly created message, but it does not elaborate on permissions, side effects, or other behavioral nuances that are not captured by 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?

The description is very concise: two sentences and a tip. It front-loads the main action and uses formatting (icon, bold) to highlight key information. Every sentence adds value without redundancy.

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?

Despite no output schema, the description explains the return value (newly created message with new id). It covers the core behavior, provides parameter examples, and distinguishes from a key sibling. For a copy operation, this is sufficient and complete.

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?

With 80% schema coverage, the baseline is 3. The description adds significant semantic value for the critical 'body' parameter by providing an example format and valid folder identifiers (inbox, archive, junkemail). This goes beyond the minimal schema description, earning a 4.

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 verb 'Copy' and the resource 'message' with a specific target 'folder within the user's mailbox'. It also explicitly distinguishes from the sibling tool 'move-mail-message', making the purpose and differentiation 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 provides a tip with an example body format and contrasts copying with moving (mentioning the alternative tool). However, it does not explicitly state when not to use it (e.g., prerequisites or conditions) beyond the move alternative, so it gets a 4 rather than a 5.

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