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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds the behavior of sorted output and availability inclusion, which is helpful but does not disclose potential rate limits or pagination. It does not contradict annotations, and adds some value beyond them.

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 a single sentence with zero waste. It front-loads the main action (given EAN, return shops) and includes key details (prices, availability, sorting) compactly. Every word adds value.

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 presence of an output schema and annotations that cover safety, the description is fairly complete. It explains the main behavior and sorting. It does not mention edge cases like no shops found or errors, but for a read-only tool with schema coverage, it covers the essential information an agent needs.

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 100%, so both 'ean' and 'country' are already documented with patterns, defaults, and enums. The description does not add additional parameter semantics beyond what the schema provides, so a baseline score of 3 is appropriate.

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's purpose: given a product EAN, return shops with prices and availability sorted cheapest-first. It uses a specific verb and resource, and differentiates from siblings by focusing on alternatives and sorting, though it doesn't explicitly name sibling tools for contrast.

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 implies usage when a user wants to find alternative shops for a product, but does not explicitly state when to use this tool instead of alternatives like get_best_price or search_product. It provides context for the sort order but lacks explicit when-not or alternative routing.

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