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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is fully covered by structured fields. The description contributes only the raw endpoint path and no additional behavioral context (pagination flow, empty-store behavior, ordering).

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, front-loaded with the verb and resource, with a useful gloss for 'zones'. Nothing extraneous.

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, annotation-covered, fully documented two-parameter list tool with no output schema, the definition is nearly sufficient. The only shortfall is the absence of any note on pagination behavior or relation to shipping methods.

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%, with both page and limit documented including defaults and the next_page chaining hint. The description adds nothing beyond the schema, so 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?

States a specific verb+resource (list shipping zones) and clarifies the domain concept in a parenthetical, mapping cleanly to GET /v1/zones. It doesn't differentiate itself from siblings explicitly, but the resource name is unambiguous among the list_* family.

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 implied by the resource name — an agent would call this when it needs shipping regions — but there is no explicit when-to-use, prerequisite, or alternative (e.g., list_shipping_methods is a nearby sibling that an agent could confuse with zones).

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