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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds meaningful context beyond that: a paid model ($0.002 USDC per successful call via x402, failed calls not charged), the result cap of 12 with a total-matching count, and per-country currency behavior. These are real behavioral traits an agent needs before invoking it.

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?

A single dense paragraph, but it is front-loaded with the core purpose and coverage before the return fields and pricing. The pricing sentence is verbose but earns its place for a cost-sensitive agent. Minor redundancy with the output schema is the only inefficiency.

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?

Output schema exists, so return-field explanation is optional but the description still usefully adds the top-12 cap and total-match count. With annotations covering read-only openness and params fully documented, the only missing piece is explicit routing against sibling tools. Otherwise complete for a simple two-param search.

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%, with both q (2-80 chars, shop language) and country (default de, enum of five values) fully documented in the schema. The description only reiterates the currency set implied by country choice, so it adds little beyond the schema. Baseline 3 applies.

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+resource (product search) with explicit scope: MediaMarkt/MediaWorld across DE, AT, CH, IT, PL. It also names the data source (schema.org product list on the public search page), which tells an agent exactly what it is retrieving and clearly distinguishes it from the many other ecommerce 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?

The country coverage implicitly defines when to reach for this tool, and the note that a category/brand match returns that page's top products clarifies expected behavior. But it never names an alternative tool or states when NOT to use it, so guidance is inferred rather than explicit.

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