Similar and complementary products

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

Annotations already declare this a safe, idempotent, non-destructive read, so the bar is lower; the description still adds real behavioral value by disclosing the ~20-item result size and the important caveat that complementary lists are empty for most products. It does not mention pagination or ordering, which keeps it from a 5.

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 short sentences, front-loaded with the core action and modes followed by usage triggers. No redundant or filler text; every sentence maps to a distinct decision the agent needs to make.

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?

An output schema exists, so return-value explanation is not needed, and the description still summarizes the payload (prices and stock). Usage conditions, both modes, and the empty-complementary edge case are all covered for a 3-parameter, 1-required tool.

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%, including a documented enum for kind and the slug/id pattern for product, so the schema already carries parameter meaning. The description restates the kind semantics, adding no syntax or format detail beyond it; 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?

Specific verb and resource ('List alternatives to a product... or the products the shop pairs with it') with scope (~20 items) and payload (prices and stock) stated up front. The two modes are clearly distinguished, which separates it from generic siblings like kh_search and kh_find_cheapest.

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?

Explicit when-to-use triggers are given: out-of-stock, too expensive, or building a routine/bundle. It stops short of naming an alternative sibling (e.g. kh_find_cheapest) for the price-shopping case, so routing is strong but not fully closed.

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