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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), and the description goes well beyond them: it defines the shape of delivery_terms, explains each place_kind value, documents null semantics, and tells the agent that an empty list means 'Incoterms on request'. It also warns that specs_display is already localized and that raw `specs` tokens must never be copied, which is exactly the kind of trap an agent would otherwise fall into.

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 payload is front-loaded: the field list comes first and the usage trigger last. The delivery_terms/specs_display clauses are dense but each carries non-obvious semantics, though the capitalized emphasis and em-dash parentheticals make the middle sentence harder to skim than necessary.

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, the description carries the burden of explaining returns, and it does so for the two trickiest fields (delivery_terms, specs_display). The remaining fields (price range, photos, HS code) are named but their formats are not described; for a simple two-param read, that gap is tolerable.

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 the baseline is 3, but the description adds meaning the schema does not: it explains the language fallback (requested language, English fallback) and how locale propagates into place_city and specs_display. Only the `slug` per-locale vs base distinction is left entirely to the schema.

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 (fetch one product's trade terms) and enumerates the concrete fields returned: MOQ, lead time, Incoterms, HS code, packaging, price range, photos, supplier. It also implicitly separates itself from search_products, which is the only sibling that could be confused with it.

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 final sentence gives an explicit trigger: use it once the person has picked a product from search_products and wants the terms. That establishes both the prerequisite and the sibling that precedes it. It doesn't state a when-not case, but the ordering guidance is unambiguous.

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