create_mailbox

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

No annotations are provided, so the description must carry the behavioral disclosure burden. It mentions 'Scope: mailbox:write', which gives some permission context, but nothing about failure modes, uniqueness constraints, or whether creation is reversible. The description relies entirely on the verb 'create' to imply 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?

The description consists of two short sentences with no filler. The core operation is front-loaded and the scope note is concise. Every word contributes meaning.

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 creation tool, the description is minimally adequate. But with no annotations and no output schema, there are missing details such as duplicate-handling behavior, whether the created mailbox is returned, and any prerequisites beyond the scope hint. These gaps make it adequate rather than complete.

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%, so the schema already documents both domain_id and local_part. The description adds no additional parameter meaning beyond what the schema provides. The baseline of 3 applies because the schema does the heavy lifting.

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 a clear verb and resource: 'Create a new mailbox.' This distinguishes it from siblings like update_mailbox, delete_mailbox, and list_mailboxes. It doesn't explicitly call out those alternatives, but the operation is unambiguous.

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?

No guidance is given about when to use this tool versus alternatives. An agent must infer that creating a new box is distinct from updating or deleting an existing one. There is no mention of prerequisites, such as checking address availability first.

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