get_variantsRetrieve all variants for a Printful catalog product or fetch a single variant by ID; pass either product_id or variant_id to get the right variant data.
Get variants for a catalog product, or one variant by variant id. Pass product_id or variant_id, not both.
| Name | Required | Description | Default |
|---|---|---|---|
| product_id | No | ||
| variant_id | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds the mutually exclusive parameter rule but does not mention pagination, return shape, or behavior when neither parameter is supplied.
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 core operation and immediately followed by the key parameter constraint. There is no wasted wording.
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 simple two-parameter read tool, the description is adequate for selection and invocation. However, with no output schema, it could do more to set expectations about return structure or pagination for product-level variant listing.
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?
With 0% schema description coverage, the description carries the burden and does well: product_id means retrieve variants for a product, variant_id means retrieve one variant, and the two are mutually exclusive. The main gap is that required parameters are 0, yet the description does not clarify what happens if neither id is provided.
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 names a specific verb and resource (get variants) and clearly distinguishes two modes: all variants for a product versus one variant by id. This is enough to separate it from siblings such as get_product or search_catalog.
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?
It explicitly tells the caller to pass product_id or variant_id, and adds the important exclusion 'not both.' It does not name alternative tools or explain the neither-parameter case, but the core usage condition is clear.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.