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

Annotations already cover readOnly, idempotent and openWorld. The description adds useful context beyond those: the return payload (best/average price, offers, specs, test scores), the privacy constraint that shop owner names and contact data are never returned, and that it reads only public data.

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?

Three sentences and front-loaded with the core action and the id format. The return-value list is a bit dense but each item is relevant since there's no output schema.

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 does the work of summarizing return fields (prices, offers, specs, test scores, link). Its market/language/offers defaults live in the schema, so nothing critical is missing; only the sibling relationship remains implied.

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% and both enums are documented in the schema. Description mentions the product_id format (including a link example such as "...-a2795961.html") but adds little beyond what the schema already says.

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 says exactly what it retrieves: 'Get one Geizhals product by its product_id', making it clear this is a single-item detail lookup rather than a listing or search. It also tells the agent where the id comes from (geizhals_search_products or a product URL), so it's distinguishable from search.

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 a clear entry point (use search or a Geizhals link to get the product_id) but doesn't explicitly say when to use it instead of geizhals_get_price_history, which is in the same family. No explicit exclusions are given.

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