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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered; the description earns credit by adding the post-condition consequence that future mail creation will require an explicit sender address. It still does not say whether the clear is immediate or reversible, or what the response contains, but the key behavioral ripple effect is disclosed.

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?

Two short sentences with no filler; the action is front-loaded and the consequence follows immediately. Every sentence carries information the agent needs.

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?

An output schema exists, so return values need no explanation, and annotations cover destructiveness and idempotency. The remaining gap is the undocumented required 'confirm' parameter, which for a destructive operation is a meaningful omission an agent could get wrong.

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?

There is one required parameter, 'confirm' (boolean), with 0% schema description coverage, and the description never mentions it or explains what confirming entails. With zero schema coverage the description is expected to compensate, and it does not.

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?

States a specific verb and resource ('Clear your saved return address'), which is unambiguous against siblings like set_return_address and get_return_address even though they are not named. The scope is exactly one object (the saved address), so an agent can distinguish it without opening the schema.

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?

Usage is implied rather than stated: the agent learns that clearing has a downstream cost ('you will need to provide a sender address when creating new mail'), which implicitly frames when this is appropriate. There is no explicit when-not guidance or named alternative such as set_return_address for overwriting rather than removing.

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