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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuine context by enumerating the data the caller gets back (per-store prices, price history, verdict, specs, reviews, second-hand listings, updates, Q&A), which matters because there is no output schema. It does not mention what happens for an unknown product name or EAN, a minor gap.

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?

Two sentences, front-loaded with the resource and its contents, followed by the sibling routing hint. The enumeration is long but each item is informative; no filler sentences. Slightly dense, but nothing that could be cut without losing coverage of what is returned.

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?

For a one-parameter read-only lookup with no output schema, the description carries the necessary burden by describing the returned data categories and by routing to the multi-product sibling. Nothing an agent needs in order to select and call this tool is missing.

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% and the single parameter already documents that it accepts a product name such as "Galaxy A16 128GB" or an EAN. The description adds no further meaning about the identifier format or matching behavior, so the 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 resource (one product from the comparator) and enumerates exactly what it returns: price per store, price history, price verdict, specs, reviews, second-hand, updates and Q&A. It also names the sibling it is not, product_prijs, so an agent can distinguish the two tools without inspecting either schema.

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 final sentence gives an explicit routing rule: use product_prijs when comparing multiple products side by side, which by contrast means this tool is for a single product. When-to-use and the alternative are both stated rather than inferred.

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