Variants

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is fully covered. The description adds one genuinely useful behavioral fact — that pricing is per-variant and cheapest-per-variant — but says nothing about how many variants come back, ordering, or whether all configurations or only priced ones are returned.

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?

One compact sentence that front-loads the core idea (sibling variants) and then the pricing detail. Nothing is redundant; the only weakness is that the fragmentary phrasing takes a moment longer to parse than a verb-led sentence would.

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?

For a one-parameter, read-only lookup with full schema coverage and rich annotations, the description covers what the tool returns well enough to call it correctly. Without an output schema, a brief note on result shape or variant count would have closed the last gap.

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 product parameter, and the schema already explains that it accepts a UUID or a torob.com URL plus its length bounds. The description adds no further meaning about the identifier, which is acceptable but adds nothing beyond the structured field.

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?

The description identifies the resource (sibling variants of a given product) and the key payload (each variant's cheapest price), which is enough to tell it apart from tb_product or tb_price_history. It is a noun phrase rather than a verb-led statement, and it never distinguishes itself from the close neighbour tb_similar, so it stops short of a 5.

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?

There is no guidance on when to call this instead of tb_product, tb_similar, tb_cheapest, or tb_compare. The agent must infer from the name alone that this is the right tool when it wants variant-level pricing rather than a single product's data.

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