Compare products

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower, yet the description still adds substantive behavior: the shape of `differences`, the null-means-nothing-listed convention, the meaning of `cheapest`, and the 'One request per product' operational constraint. This is useful disclosure beyond the annotations.

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 purpose sentence, then usage, then field semantics, with no filler. The trailing 'One request per product' is slightly cryptic in isolation but still earns its place as an operational hint.

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 carries the return-value burden and does so adequately, explaining `differences`, `cheapest`, and the price window. A little more detail on the price-window fields would make it fully complete, but nothing essential for calling the 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 coverage is 100% and there is a single parameter, so the schema already fully documents `products`. The description's only added semantics are the ordering guarantee tying `differences` values to the order of `products`; otherwise 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 verb and resource ('Side-by-side comparison of 2-5 products') and enumerates exactly what is returned: differing specs, price window, cheapest flag. It is clearly distinct from a single-product tool like tb_product, though it does not distinguish itself from the semantically adjacent tb_cheapest / tb_best_value siblings.

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?

'Use after tb_search / tb_similar to choose between models' gives an explicit workflow position and names the tools that precede it. It does not state when NOT to use it versus tb_cheapest or tb_best_value, so it stops short of full alternative routing.

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