Variants

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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds real behavioral value the annotations don't: the result set is variants each priced at their cheapest, and the returned option `id` is designed to be chained into other tools.

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 short sentences, front-loaded with the resource and its payoff, then the usage and chaining instruction. Zero filler.

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 partially cover it (variants, cheapest price, reusable option ids). It still doesn't sketch the response fields beyond variant attributes and price, leaving a small gap for a multi-variant list 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?

The single `product` parameter is fully documented in the schema at 100% coverage, including accepted id/path/URL forms. The description adds nothing about the input parameter—its 'id' mention refers to returned option ids, not the input—so 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 resource (product variants) and the distinguishing attribute set (storage+RAM, colour, region) plus what each carries (its own cheapest price). An agent can tell it apart from tb_offers, tb_compare, or tb_product 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?

Gives a concrete question it answers ('what does the 512 GB version cost') and an explicit follow-up: pass an option's `id` to the other tools. It lacks any when-not or named alternative sibling, so it stops short of a 5.

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