forward-mail-message

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

Annotations declare destructiveHint: true and readOnlyHint: false. The description adds that the method saves the message in the Sent Items folder, which implies sending. It also mentions HTTP 400 errors for invalid combinations. This adds useful behavioral 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?

The description is well-structured with bullet points and a tip, making it easy to scan. It is informative but slightly verbose; a few sentences could be trimmed without losing clarity.

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?

Given the complexity (two formats, nested objects) and no output schema, the description covers the main use cases and constraints. However, it does not explain the return value or confirm that the forwarded email is sent immediately. The tip implies server-side handling but is vague. It could be more complete about outcome.

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 coverage is 80%, so the baseline is 3. The description adds significant value by explaining parameter constraints: specifying both comment and body returns 400, toRecipients is required, and toRecipients can be in the parameter or in the message object. It clarifies usage of key parameters beyond the schema.

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 forwards a message using JSON or MIME format, with specific verb and resource. It distinguishes from creating a draft by mentioning 'Alternatively, create a draft to forward a message, and send it later.' The tip 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 provides explicit when-to-use guidance for JSON vs MIME formats, including constraints on parameters like comment/body and toRecipients. It also mentions the alternative of creating a draft. However, it does not explicitly compare to other sibling tools like send-mail or reply-mail-message.

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