Add Mailbox Forwarding

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

Annotations (destructiveHint=true, idempotentHint=true) are present, but the description adds valuable behavioral context: confirmation email, local copy retention, spam exclusion. No contradiction with annotations. However, it does not describe idempotency behavior or potential side effects beyond forwarding creation.

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 a single concise sentence with clear front-loading of the main action. However, it could be structured as a list for better readability. 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?

The description explains the confirmation process and key behaviors, but it omits important context such as prerequisites (e.g., mailbox existence), parameter usage, error conditions, or how idempotency works. Given the tool's complexity and available output schema, it is minimally adequate.

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 67%, but the description provides no explanation of the parameters. It does not clarify what 'id' or 'destination' represent, nor the purpose of the idempotency_key. With moderate coverage, the description should compensate but fails.

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 action ('create mailbox forwarding') with specific behavioral details: sends confirmation email, delivery only after confirmation, keeps local copy, excludes spam. It effectively distinguishes from siblings like list and delete forwarding.

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 implies the tool is used to set up forwarding with confirmation, but it does not explicitly state when to use it vs. alternatives (e.g., if no confirmation needed) or provide prerequisites. There is no guidance on when not to use.

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