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

Annotation coverage is real (readOnlyHint=false, idempotentHint=false), yet the description adds the genuinely non-obvious behavior that the call mutates nothing and instead yields a preview plus a confirmation link the merchant must act on. This is valuable context an agent could not derive from the schema or annotations.

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 important content (scope and the preview/confirmation behavior) is front-loaded, but the sentence 'Money is integer minor units (cents)' is irrelevant boilerplate — no parameter in this schema deals with money — and risks confusing the agent. Removing it would tighten the definition considerably.

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?

There is no output schema, and the description compensates by stating what the call returns (a diff preview and a confirmation link) and how the change actually takes effect. With all three parameters documented in the schema, an agent has what it needs to invoke this correctly.

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 100%, so mode semantics, ISO code format, the empty-list-means-anywhere rule and the 300-item cap are already fully documented in the schema. The description adds no parameter information beyond that, so the baseline 3 applies.

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 (set the shop's shipping destinations), and the rest explains the workflow. It does not explicitly distinguish itself from close siblings like shipping_set_zones or shipping_set_method, but the scope is unambiguous enough to select correctly.

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 clarifies the unusual apply-model (preview + confirmation link, merchant-only execution), which is real usage context. However, it never says when to use this versus shipping_set_zones/shipping_set_defaults/shipping_set_method, so the agent must infer routing 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.