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

Annotations already flag destructiveHint=true and idempotentHint=true, and the description adds substantive context on top: sessions disconnect within five seconds, stored messages and address survive, account scope is required, and credentials are all revoked. It also documents both supported authentication paths and the key-retention hazard, which no annotation conveys.

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 primary effect is front-loaded in the first clause, and every sentence carries operational content. The key-retention warning is restated once from the schema, which is slight redundancy, but it is framed as a chat-sharing caution rather than a verbatim repeat.

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 destructive, open-world mutation with no output schema, the description covers what is destroyed, what persists, auth requirements, timing, and recovery. It omits any indication of what the call returns on success or failure, which is the main remaining gap.

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%, so baseline is 3, but the description adds meaning the schema lacks: 'key' is one of two mutually exclusive auth options (the other being the Authorization: Bearer header), and 'request_id' should be new for a re-enable versus reused verbatim on a retry. That distinction is genuinely useful and not obvious from the field descriptions alone.

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?

Uses a specific verb and resource ('Disable your mailbox and revoke ALL its credentials') and immediately states scope — what stops working, what is retained, and what the reversal path is. An agent can distinguish this from mail_enable, mail_credential_revoke, and mail_credential_create without opening any 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?

Gives clear situational context: this is a full mailbox shutdown plus credential revocation, and re-enabling requires a fresh request_id and new credentials. It does not explicitly say when to prefer the narrower mail_credential_revoke sibling, so a small routing gap remains.

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