update_variation

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

The description discloses a key behavioral trait beyond the annotations: that only specified fields are updated and omitted fields remain unchanged. This complements the idempotentHint annotation and adds context about the operation's partial-update nature. It does not contradict the annotations.

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 a single 17-word sentence that is front-loaded with the verb and resource. It includes essential usage guidance without any fluff or unnecessary details.

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 14 parameters, nested objects, and enums, but the description only lists a few example fields. It does not mention the required product_id and id, nor does it clarify the return value (no output schema). The partial-update guidance is helpful, but the overall description is minimal given the tool's complexity.

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 input schema already provides descriptions for all 14 parameters (100% coverage), establishing a baseline of 3. The description adds cross-cutting semantic value by clarifying that only provided fields are changed, which affects how all parameters should be interpreted. It does not repeat the schema descriptions directly.

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 clearly states the action (update), the resource (a variation), and key fields (price, stock, SKU). It distinguishes the tool from siblings like update_product and create_variation by specifying it applies to variations and is an update operation.

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 instruction 'Only include fields you want to change' provides a useful usage parameter guideline, implying partial-update behavior. However, it does not explicitly state when to use this tool over alternatives like batch_update_variations or get_variation, nor does it mention any exclusions or prerequisites.

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