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

Although annotations already declare destructiveHint=true and readOnlyHint=false, the description adds substantial context beyond them: irreversibility, loss of aliases/forwarding, no recovery, server-side validation that nothing is deleted when the mailbox doesn't exist or the list couldn't be retrieved, and how to interpret ambiguous responses. It stops short of being perfect only because the response-interpretation rules, while detailed, are lengthy and partly operational rather than purely descriptive.

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 destructive warning is correctly front-loaded and the sentence order follows the decision flow (what it does → consequences → check first → confirm → interpret response). It is long, but for an irreversible operation most sentences earn their place; a few (e.g. the repeated no-deletion scenarios) are slightly redundant.

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?

With no output schema and two parameters fully documented, the description carries the remaining burden excellently — it explains the possible response states (verified deletion, 'accepted but unverified', still present, confirmation_required) and warns never to report success unless the server re-checked. Nothing needed to call and interpret this tool correctly is missing.

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 100% — the schema already explains that domain is the domain and local_part is the part before the @, with format constraints. The description adds the customer-facing example 'info@example.de' but no syntax beyond the schema, so the baseline 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 opening sentence states a specific verb and resource — permanently deleting an email mailbox including all its mails, aliases and forwarding. It explicitly contrasts with the sibling create_email_account ('a newly created mailbox with the same name is EMPTY'), so the 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?

It gives explicit pre-conditions and routing: first look up mailboxes with get_email_accounts, name the exact address to the customer, ask for an explicit confirmation with a sample phrasing, advise on backups, and only call after a clear 'yes'. This is a complete when-to-use and how-to-proceed protocol.

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