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

Annotations already establish this as a safe read-only tool. The description adds valuable behavioral detail beyond annotations: the address format, mailbox code placement, and the c/o name convention with an explicit warning never to invent a name.

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 two tightly written sentences with no wasted text. It front-loads the primary purpose and then adds the important style-specific formatting rule.

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 read-only getter with fully described parameters and safety annotations, the description supplies the remaining needed context: what the returned address looks like and how registration-oriented name formatting works. No output schema exists, but the description adequately explains the returned content.

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 100%, so parameter definitions are already documented. The description adds meaningful semantics for the "person" style, explaining the resulting name format and fallback behavior, which goes beyond the enum 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 clearly identifies the resource as the user's postal address for letters and parcels, including the mailbox code line. It is specific but does not explicitly differentiate from siblings such as get_account, though no close alternative is apparent.

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 states when the address is useful—for letters/parcels and registrations needing a first and last name—and explains when to choose the "person" style. It does not list exclusions or named alternatives, but the usage context is clear.

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