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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, and the description adds important operational behavior: non-US market values are refused without searching and do not charge credits, unknown/foreign/expired conversation ids are rejected, and any invalid selected_item_ids value rejects the whole call. These details go beyond the annotations and help the agent avoid failed or unintended calls.

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 description is front-loaded with purpose, then immediately gives the key parameter usage rules and exclusions. Every sentence carries actionable information, with no 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?

Given the full input schema, annotations, and no output schema, the description provides enough context to call the tool correctly. It covers scope, usage patterns, continuation semantics, identifier handling, and refusal behavior for unsupported markets and invalid ids.

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 schema already documents parameters in detail. The description still adds meaningful guidance for query, conversation_id, and selected_item_ids, including thread continuation, copying item_id values unchanged, not parsing them, and the all-or-nothing rejection behavior for invalid selected_item_ids.

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 states a specific verb cluster (find, compare, answer questions) and resource (products in the US catalog), with clear scope. It also explicitly excludes carts, orders, coupons, account login, and non-US markets, so an agent can distinguish this tool's role even without siblings.

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?

It gives explicit usage rules: put the shopper request in query, use conversation_id to continue a thread, and copy item_id values into selected_item_ids to refer to shown products. It also states when not to use the tool, covering cart, orders, coupons, account login, and non-US markets.

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