Compare products

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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds real behavioral context beyond that: null means a missing spec, identical rows are folded into `same_specs`, and unknown ids are dropped and reported in `missing_ids`.

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?

Front-loaded with the core action in the first clause, then dense but useful detail about the return semantics. Two short paragraphs, no filler, though the second paragraph is tightly packed.

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 values need not be explained, yet the description still clarifies the key semantic conventions (ordering, nulls, folding, missing ids). The only gap is absence of explicit alternative-tool routing.

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 coverage is 100% for the single parameter, so baseline is 3. The description adds meaning by stating that `values` follow the order of `products`, which tells the agent that input ordering is preserved and significant.

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 with scope: 'Compare 2-4 products side by side: price and rating, then the spec rows where they differ.' An agent can tell this is a multi-product comparison rather than a single-product lookup, though no sibling (e.g. dk_similar, dk_product) is named to sharpen the boundary.

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?

'Works best for products of the same category' implies when the tool is appropriate, and the 2-4 bound is stated. However, there is no explicit when-to-use/when-not guidance and no routing to alternatives such as dk_product for a single item.

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