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

With no annotations provided, the description carries the full burden of behavioral disclosure. It clearly states that the tool is BILLABLE, requires authentication, stages rather than instantly creates, returns an actionId, and that the password appears exactly once. This is exemplary transparency for a paid creation flow.

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 description is long but every sentence carries operational value. It is front-loaded with the billing warning, then prerequisites, parameters, workflow, and critical password-handling instruction. The structure makes it easy to scan and act on.

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?

Given the complexity, the absence of output schema, and lack of annotations, this description is remarkably complete. It explains prerequisites, billing, the two-step confirmation flow, what the returned actionId means, what the result contains, and what to do with the password and client settings. An agent has enough to call the tool correctly and follow through.

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 only 20% (sessionKey has a description), so the description must compensate. It adds substantive meaning to all other params: domain must be ACTIVE, localPart is the part before the @, packageId comes from listMailPlans with no default, and term has explicit values with a default. It greatly exceeds what the schema provides.

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 says 'Stage creation of a paid mailbox on a mail-enabled domain,' which is a specific verb and resource. It also distinguishes this staging action from the later executeConfirmedAction step and from related mail tools. An agent can immediately tell what this tool is for and what it is not.

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?

The description gives an explicit workflow: get a quote with getMailboxQuote, confirm price with the user, then call executeConfirmedAction with the returned actionId. It also says the user can later change the password with setMailboxPassword, providing clear guidance on when to use related tools.

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