Create variant

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

With no annotations, the description carries the full behavior-transparency burden. It goes beyond the obvious by disclosing the media rule: at most one video, a video requires an image in the same list, and the video_id must be READY after an upload/polling workflow. It does not disclose potential failure modes, permissions, or the response shape, but the validation detail is substantial.

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?

Three dense sentences with no filler. The purpose is up front, required fields immediately follow, and the media edge case is given practical, actionable detail. The final pointer to get_operation_schema avoids bulk while preserving completeness.

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 create operation with a nested request object and no output schema, the description covers the main legal hazards and gives an explicit pointer to the authoritative schema. However, it leaves some context implicit, such as what the response contains and whether the operation can fail due to product state, relying instead on get_operation_schema discovery.

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?

Even though schema coverage for the single variant parameter is 100%, the description adds crucial semantic depth beyond the schema's generic 'matching the CreateVariantRequest' text. It names required fields and explains non-obvious media/video constraints, significantly helping an agent construct a valid parameter object.

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 precise action ('Create a new variant') and the resource ('under an existing product'), tying it directly to create_variant while differentiating it from create_product and update_variant. The added phrase '(sellable item)' clarifies the domain without ambiguity.

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 usage context: the variant belongs under an existing product, and the required name and product_id are stated. It also explains the prerequisite for media/videos and directs to get_operation_schema for exact shape. It does not explicitly name alternatives or state when not to use the tool, so it misses a 5.

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