get_mailbox

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

Annotations already establish readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuinely new behavioral context: the PMB number is gated on USPS Form 1583 verification, implying the address may be incomplete until that completes, and it discloses that inbound documents arrive through a separate private intake alias rather than through this call. That gating condition is exactly the kind of state-dependent detail annotations cannot express.

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 core answer is front-loaded and compact, but the second sentence about inbound context via a private intake alias is tangential to a tool that returns a mailing address and risks confusing the agent about what this call actually returns. Two sentences, one of which does not clearly earn its place.

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?

With an output schema present, return values need no explanation, and for a zero-parameter read tool the description covers the resource, its location, and the verification precondition. The only residual gap is the absence of any guidance on what to do when the PMB has not yet been assigned or how this relates to the inbox-oriented siblings.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline applies. The description does not waste words inventing parameter guidance, which is correct here.

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 first sentence gives a specific verb and resource — retrieve the agent's real mailing address (street address + PMB) at the Manhattan Beach, CA facility — which is concrete enough to separate it from the inbox/scan siblings. It stops short of explicitly contrasting itself with similarly named tools such as get_mailbox_md or the get_agent_inbox_* family, and the trailing sentence about inbound context muddies the single-purpose framing.

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?

Usage is only implied: an agent infers it should call this when it needs its own postal address, and the Form 1583 note hints that a PMB may not yet exist. There is no explicit when-to-use, when-not-to-use, or routing to an alternative tool, even though several siblings (get_mailbox_md, get_inbound_mail, list_inbound_forwarding_addresses) plausibly overlap.

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