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

Annotations already declare destructiveHint=true, idempotentHint=false, and openWorldHint=true, so the risk profile is covered. The description adds the US-only constraint and the optional return-address behavior, but says nothing about whether the new address becomes the default or what happens on duplicate titles.

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?

A single tight sentence with no filler; the core action and the optional variant are front-loaded.

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 non-idempotent mutation with nested address objects and no output schema, the description should clarify return behavior (ID? created object?) and address validation rules. The safety profile is covered by annotations, so this is adequate but not 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 coverage is 67% and the schema already documents the return_address default ('Default: the origin') as well as most field descriptions. The description's mention of an optional separate return address mirrors what the schema states, adding marginal new meaning.

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?

States a specific verb and resource ('Adds a US Ship From Address') with a scope qualifier (US) and the return-address option. It's clearly distinct from list/update/delete siblings by name, though the description never names them explicitly.

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 on when to use this versus update_ship_from_address, list_ship_from_addresses, or set_default_ship_from_address, and no prerequisites (e.g., whether an address must be validated first) are given. The agent must infer usage from the name alone.

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