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

Annotations already declare destructiveHint=true and non-idempotent, so the safety profile is known; the description goes further by specifying that all emails and attachments are destroyed, that the address can never be re-obtained by others, that restoration yields an empty mailbox, and that no confirmation prompt occurs. That is materially more than the annotations convey.

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?

Three short sentences, front-loaded with the destructive action, then recoverability, then the no-confirmation warning. Every sentence carries decision-relevant information with no filler.

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 single-parameter destructive tool with no output schema, the description covers what is destroyed, whether it is recoverable, and the lack of a confirmation gate — the exact facts an agent needs before invoking it. Annotations handle the safety hints.

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 description coverage is 100% and the single "mailbox" parameter is fully documented in the schema (id or full email address). The description adds no syntax or format detail beyond it, so the baseline 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?

States a specific verb and resource ("Permanently delete a mailbox") plus the blast radius ("all of its emails and attachments"), which immediately separates it from siblings like restore_mailbox and search_deleted_mailboxes. An agent can identify the operation 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?

It names the recovery counterpart ("restore_mailbox can bring it back (empty) later") and flags that there is "No confirmation step," which tells the agent this executes immediately. It does not give an explicit when-to-prefer-this-over-alternatives rule, but the context is clear enough for routing.

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