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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds clarity by stating the tool is 'read-only' and describes the output (best price, 30-day price stats, offer link). No contradictions; the description complements annotations well.

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 bilingual (German and English), which adds some redundancy. However, each sentence serves a purpose: purpose, return info, constraint. It is well-structured and front-loaded. Slightly longer than necessary due to dual language, but still efficient.

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 annotations and output schema, the description provides sufficient context: input constraints, return values, and relationship to sibling tool. It lacks information about error handling or not-found cases, but for a read-only lookup tool, it is largely complete.

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 baseline is 3. The description adds the important constraint that exactly one of 'id' or 'url' must be specified, which is not captured in the schema. This additional semantic guidance improves parameter usage.

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 clearly states the tool looks up a specific product by ID or URL, returning best price, 30-day price stats, and offer link. It distinguishes from sibling 'search_offers' by focusing on concrete product lookup vs general search. Purpose is specific and unambiguous.

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 description explains that exactly one of 'id' or 'url' must be provided, and mentions that 'id' can be an ASIN or externalId from search_offers, linking to the sibling tool. However, it does not explicitly state when to use this tool versus alternatives or when not to use it.

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