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

Annotations already declare readOnlyHint=true and destructiveHint=false; the description reinforces this with "nothing is ordered or charged" and identifies the underlying POST /price endpoint. It also discloses the shape of the result (per-item and shipping breakdown), which the absent output schema would otherwise leave unknown.

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?

One dense sentence plus a short parenthetical; the purpose and the cost breakdown are front-loaded and the non-mutating clarification is appended. No sentence is filler.

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 8 parameters, no output schema, and required-address requirements, the description supplies the missing return-value picture (per-item partner/customer price, tax, shipping total) and the quote semantics. Nothing an agent needs to call it correctly is absent.

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 all 8 parameters are documented in structured data, making 3 the baseline. The description adds the framing that items are SKUs shipped to an address but does not explain currency_code, ship_type, or quantity limits beyond what the schema already provides.

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 ("Estimate the cost of an order") and enumerates the outputs (partner price, customer price and tax, shipping total), which separates it from a shipping-only quote. It does not name the close sibling gooten_get_shipping_estimate explicitly, so the differentiation is inferred from scope rather than stated.

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?

"before placing it" gives a clear usage context, and "a quote: nothing is ordered or charged" tells the agent this is non-committal. No exclusions or named alternatives are given, so the agent must infer that shipping-only questions belong to gooten_get_shipping_estimate.

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