create_inbox

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

Since no annotations are provided, the description carries the full burden. It discloses key behaviors: the address is permanent until deletion, messages expire based on retention window, label requires a paid plan (reported in ignored_fields on free), and retention_hours are capped. This is meaningful, though it omits side effects like authentication or whether repeated calls create new inboxes each time.

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 concise and front-loaded: it opens with purpose and usage, then adds persistence and parameter notes. Every sentence adds value with no redundancy. It is well organized and easy to scan.

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?

While the description covers purpose, usage, and some parameter behavior, it leaves `prefix` unexplained and does not clarify whether each call creates a new inbox or returns an existing one. Given the tool has no output schema and no annotations, these omissions leave the agent with uncertain behavior on repeated calls and on an entire parameter.

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 0%, so the description must explain parameters. It explains label (paid plan dependency) and retention_hours (optional, capped), but completely omits the `prefix` parameter. Without a description, an agent cannot know what prefix does. This is a significant gap for one of three parameters.

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 clearly states the function ('Open an email inbox and return its address') and gives a specific use case ('when you need an address to sign up for a service or to receive a one-time code'). This sets it apart from sibling tools like list_inboxes or read_messages, which are about listing or reading, not creation.

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 provides explicit usage context ('Use this when you need an address to sign up for a service or to receive a one-time code'), but it does not mention when not to use it or name alternatives directly. The context is clear, but there are no exclusions or comparative routing.

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