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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds behavioral context beyond annotations: output format (TOON, compact YAML-like), the found=false flag for unresolved IDs, error conditions (>50 identifiers or none), and the request limit (min 1 / max 50). This is substantive behavioral disclosure that helps an agent predict outcomes.

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 well-structured with labeled sections (USE WHEN, INPUT, OUTPUT, NOT FOR, ERRORS). It is front-loaded with the purpose and delivers a lot of actionable information in a compact, scannable format. No redundant sentences or fluff; each section earns its place.

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?

There is no output schema, so the description must explain the return format — it does, via the TOON format and enumerated fields, plus the found=false failure mode. It also covers input constraints (DAN/GTIN lengths, count limits) and error handling. Combined with the annotations, everything an agent needs to invoke this tool correctly is present.

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% — both parameters (dans, gtins) have descriptive text including digit length and preference. The description adds the rule that multiple products can be combined (min 1 / max 50), which is not present in the schema, and clarifies the 'and/or' relationship between the two parameter groups. This goes beyond repeating schema info, though it could have included examples of valid input formats.

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 states a specific verb and resource ('Retrieve detailed product information for dm-drogeriemarkt products') and enumerates the exact kind of data it returns (ingredients, nutrition, allergens, etc.). It also explicitly lists what it is NOT for (prices, availability, stock, reviews, recommendations), distinguishing it from sibling tools like searchProducts and findNearbyStores.

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 gives an explicit 'USE WHEN' list of use cases and a 'NOT FOR' list of exclusions. It further instructs to 'Use search tool first if only product name is known', directly routing the agent to the appropriate sibling. This is explicit when-to-use and when-not-to-use guidance with an alternative.

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