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

With no annotations, the description usefully discloses that existing messages remain in the box and retain the alias they arrived on. However, it omits permissions, reversibility, what happens to future mail sent to the alias, and error behavior for a destructive mutation.

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, front-loaded with the effect and then the relevant caveat about existing messages. There is no wasted text.

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?

For a simple two-parameter mutation with fully documented schema fields and no output schema, the description gives the key behavioral outcome and message-retention caveat. It could be more complete about prerequisites or reversibility, but the core invocation context is present.

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?

The schema has 100% description coverage, and the descriptions explain both address and alias clearly, including pointing to list_mailboxes. The free-text description adds no parameter-specific semantics beyond that schema content, so the baseline score of 3 applies.

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 states the concrete effect of removing a mailbox alias: an address no longer delivers into the box. It is clear but does not explicitly name 'alias' or distinguish this from nearby tools such as remove_mailbox_holder or remove_suppression without relying on the title.

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?

It does not say when to use this tool versus add_mailbox_alias, remove_mailbox_holder, or other removal tools. Usage is only implied by the tool name/title and the address/alias parameters.

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