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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and a closed world, so safety is covered; the description goes further by disclosing the aggregate semantics of the response (lowest total price incl. shipping, cheapest shop, shop count, next-day availability). It stops short of auth requirements, rate limits, or empty-result behavior, so it is strong but not exhaustive.

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 tight sentences, front-loaded with what it searches, then what it returns, then the hand-off to the sibling. Every clause carries information; nothing is padding.

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 usefully describes the return shape, and annotations cover the safety profile, so the agent has what it needs for an 8-parameter tool. Minor gaps remain: pagination/limit interaction with the 24 cap and no-result handling are unaddressed.

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 each parameter carries its own explanation (shop, sort options, price bounds, delivery days, limit range), so the schema already does the heavy lifting. The description adds no parameter-level syntax or default information beyond it, which is the baseline-3 case.

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 (Search) plus the resource and domain (products and travel eSIM data plans at Dutch partner shops), and further pins the result granularity (one entry per product, not per shop). An agent can distinguish it from compare_prices/compare_products without opening a 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?

Explicitly routes the complementary case: 'Use compare_prices with product_key to see every shop for one product,' giving both the alternative tool and the key that selects it. Discovery-vs-drill-down division of labor is unambiguous.

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