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

Goes well beyond the annotations by disclosing that the call itself mutates nothing, returns a preview of pending changes plus a confirmation link, and that only the merchant can commit on that page. This is exactly the context an agent needs, since readOnlyHint=false alone would suggest an immediate write.

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?

Three short sentences, front-loaded with the action and immediately followed by the critical preview caveat. The money/units sentence is the only element that does not earn its place for this parameter set.

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 no output schema and no annotations describing the staged flow, the description correctly carries that burden and explains the confirmation link. It stops short of describing error behavior or how zone conflicts resolve, which are minor residual gaps for a 2-param tool.

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 mode/zones/rule/area are already fully documented in the schema, making 3 the baseline. The one extra note, 'Money is integer minor units (cents)', does not map to any parameter in this schema, so it adds no usable semantic value.

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 ('Set delivery areas'), so the agent knows it configures shipping zones. It does not, however, distinguish itself from close siblings like shipping_set_countries, shipping_set_method, or shipping_set_defaults, so an agent must infer the boundary.

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 context by explaining the preview-and-confirm flow, which tells the agent this is a staged, merchant-approved operation. It never states when to prefer this tool over the sibling shipping_set_countries/set_method tools, so routing guidance is only implicit.

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