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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavior: a 10-result cap, the exact result fields returned, a 'lowest price per day where prices are published' caveat, and an explicit ranking-fairness guarantee that resolves a real trust question about paid placement.

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 dense sentences, front-loaded with the action and resource, then the return contract and ranking policy. No filler, duplication or hedging; every clause carries information an agent can act on.

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 compensates by enumerating returned fields and the result cap, and the 100%-covered schema handles parameters. It stops short of explaining empty-result behavior or how the four query modes differ in matching, which would make it fully complete.

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 query, limit and country are already fully documented, establishing a baseline of 3. The description restates the searchable keys and the result cap but adds no syntax, format or edge-case detail (e.g. partial vs exact barcode matching) beyond the schema.

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 and resource ('Searches the Verateca register of dietary supplements') plus the search keys (name, brand, ingredient, barcode), so the agent knows exactly what this tool does. It never names or contrasts with siblings such as get_product or compare_products, so differentiation must be inferred.

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?

Usage is only implied by the word 'search' and the list of accepted keys; there is no explicit statement of when to reach for this over get_product (id lookup) or get_ingredient. The 'ordered by match, never by payment' note hints at ranking intent but is not routing guidance.

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