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

Annotations cover safety (readOnlyHint, openWorldHint), and the description adds genuinely non-obvious behavior the annotations do not: billing at 1 credit per 10 sellers with a minimum of 1. It still says nothing about pagination or result caps, so not a 5.

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?

Two compact sentences: what it returns first, cost second. No filler, no restatement of the title, and the return fields are enumerated usefully.

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?

No output schema exists, but the description enumerates the returned fields (merchant, price, shipping, total, availability, delivery) and discloses cost, which is what an agent needs to decide to call it. Only country/language semantics and any result-limit behavior are 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?

Schema description coverage is 0%, so the description must carry the load. It clarifies product_id as a Google Shopping product id, but leaves country and language completely unaddressed beyond their schema defaults and type constraints.

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/scope (returns every seller's offer) and names the exact resource (a Google Shopping product_id), plus the fields returned. It is distinguishable from google_shopping_product/search, though it never names the sibling it complements.

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?

No when-to-use guidance, no alternatives, no prerequisite stated. The reference to 'a Google Shopping product_id' faintly implies you first obtain an id from google_shopping_search, but the agent must infer that entirely.

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