list_size_variantsFor a ring, chain, bracelet or anklet SKU, lists the sibling products that are the same piece in other sizes (ring sizes) or lengths (inches), each with its own SKU and URL. Empty when the piece comes in one size.
| Name | Required | Description | Default |
|---|---|---|---|
| sku | Yes | A SKU such as WCF040-5 (ring size 5) or BOX100-14 (14 inch chain). |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the behavioral disclosure burden. It explains that the tool lists sibling variants, that each variant has its own SKU and URL, and that the result is empty for single-size pieces. This provides useful behavioral detail beyond the tool name.
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?
The description is two sentences with no filler. It front-loads the tool's purpose and product scope, then adds the important empty-case caveat. Every sentence earns its place.
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 lookup tool with no output schema, the description adequately explains what the tool returns (variant SKUs and URLs), what inputs are valid, and what happens when no variants exist. Nothing essential is missing for correct invocation.
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 schema already documents the single 'sku' parameter with examples and 100% coverage, so a baseline score of 3 is appropriate. The description adds no significant parameter semantics beyond what the schema provides.
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 states a specific verb ('lists'), a specific resource (sibling products that are the same piece in other sizes or lengths), and the input domain (ring, chain, bracelet, or anklet SKU). This clearly distinguishes the tool from generic product retrieval or search tools.
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?
The description gives clear context for when to use it: when you have a SKU for a piece that may come in ring sizes or chain lengths and need its variants. It also notes the empty-result case when a piece comes in one size, though it does not explicitly name sibling tools as alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.