Update variant

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

With no annotations, the description carries full behavioral burden. It discloses non-nullability, the replacement semantics of media and stocks, the one-video-per-variant rule, the image requirement for videos, and even a documentation bug in the upstream schema. This is exceptionally rich safety-relevant information for an agent.

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 longer than average, but every sentence supplies unique guidance: alternatives, nullability, media/stocks replacement, video constraints, and an upstream documentation correction. The core merge-patch instruction is front-loaded so the agent immediately understands the central contract.

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?

The tool has a nested mutation with no annotations and no output schema, yet the description covers all major failure modes: null rejection, full-list replacement, video-image dependency, and schema misdocumentation. It also directs the agent to get_operation_schema for the unambiguous request shape, making the definition effectively complete.

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 covers id and variant, but the description adds high-value meaning: JSON Patch semantics, which fields are exceptions to the patch behavior, what nulls mean, and where to get the authoritative shape. This significantly improves agent understanding of the variant parameter beyond what the schema alone communicates.

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 explicitly states the behavior: update an existing variant via JSON Merge Patch, sending only the fields to change. It identifies the target resource and distinguishes this tool from closely related operations like bulk_update_prices by clarifying which use cases belong to which tool.

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 provides concrete when-not-to-use guidance: null values are rejected, so to clear a price the agent should use bulk_update_prices. It also tells the agent to consult get_operation_schema for the exact request shape, providing a clear path to validate the payload before invoking.

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