mailbox_register

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It does disclose idempotency, which is valuable. But it does not describe what happens on first call vs subsequent calls, whether claiming a mailbox is exclusive or shared, what the return value is, or any side effects. For a registration tool with no annotations, this is a moderate gap.

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 one concise sentence plus an idempotency hint. It is front-loaded with the action and wastes no words. It loses one point only because it could have used the space to give parameter or usage hints.

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 setup tool with 3 parameters, no annotations, and no output schema, the description is thin. It explains what the tool does but not enough about the parameters, the registration semantics (exclusive ownership? idempotent means same agent re-registers?), or what response to expect. An agent cannot confidently call this correctly on the first try.

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 0%, and the description does not explain what any of the three parameters (owner, agent_id, description) mean beyond what the schema names show. The description mentions 'agent' and 'mailbox' but adds no meaning to owner or description. Since the schema provides only names and defaults, an agent cannot infer the intended values for owner and description.

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 action: register the agent and claim its mailbox. It goes beyond a tautology by naming the resource (mailbox) and the operation (register/claim). However, it does not explicitly distinguish itself from sibling tools like mailbox_check or mailbox_send, relying on the resource name alone for differentiation.

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 implies this is a setup or onboarding call — you register before checking or sending mail. It does not state when to call it again, when not to use it, or name alternatives. The idempotency note ('safe to call again') hints at retry scenarios but no explicit guidance is given.

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