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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds useful content-level context beyond the annotations, namely that each entry carries currency, size unit, and a ships-here flag, which tells the agent what this reference data can be used for.

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 front-loaded sentence that identifies the resource first and enumerates the payload fields after. No filler, no repetition of structured data.

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 an output schema present and annotations covering safety, the description only needs to establish purpose and content, which it does fully. Nothing required to invoke a zero-parameter lookup correctly is missing.

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?

There are zero input parameters, so the baseline is 4. The description still adds meaning by positioning the tool as the authoritative source of goat_product's country_code values, which is the semantic link an agent needs.

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 names a specific resource (GOAT countries) and states exactly what it returns: the accepted values for goat_product's country_code plus currency, size unit, and shipping availability. It is unambiguous, though it does not explicitly differentiate itself from the other goat_* siblings such as goat_search_facets.

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?

By tying itself to goat_product's country_code, it implies the correct usage context: resolve a valid country value before calling goat_product. There are no explicit exclusions or named alternatives, but for a zero-parameter reference endpoint the implied usage is clear enough.

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