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

The annotations already provide destructiveHint=true, idempotentHint=true, and openWorldHint=true. The description's 'Updates' is consistent with these hints and does not contradict them, but it adds no additional behavioral details beyond what annotations already cover.

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, direct sentence with no redundant words. It conveys the essential purpose without any fluff or unnecessary detail.

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 description is minimal and does not explain what the function returns, whether it performs a partial or full update, or how it fits with the broader set of shop tools. However, given the annotations and the simplicity of an update operation, it is adequate but not rich in context.

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?

Schema coverage is 100% and every parameter has a clear description, so the baseline applies. The tool description itself does not add extra parameter context, but the schema sufficiently explains each field, including nested option_values.

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 ('Updates') and the resource ('product variant'), which distinguishes it from create/delete operations. The resource is specific enough that an agent can understand the tool's purpose from the description alone.

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 no guidance on when to use this tool versus alternatives like shop_create_variant, shop_delete_variant, or shop_update_product. It does not mention scenarios, prerequisites, or differences from similar tools, leaving the agent to infer usage from the name and parameters.

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