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

readOnlyHint=true already declares this is a safe read, so the bar is lower. The description adds useful domain context (variant ids are what inventory levels are keyed on, backing endpoint GET /variants) but says nothing about pagination behavior, even though cursor/limit params exist.

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 short clauses, all front-loaded: what it lists, what a variant is, and how to scope the call. Every sentence carries information an agent can act on.

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 read-only list tool with no output schema and full schema parameter coverage, the description is nearly sufficient; the main missing piece is any note on paging semantics or result ordering, which the schema only partially implies.

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 description coverage is 100%, so all ten parameters are already documented in the schema, establishing a baseline of 3. The description only gestures at the sku/items_ids filtering modes without adding syntax or defaults beyond what the schema provides.

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?

Names a specific verb+resource ('List item variants') and immediately defines the domain term ('the sellable SKUs'), distinguishing it from the sibling loyverse_list_items. It also states the scope of filtering and the significance of the returned ids.

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?

'optionally for given items or one SKU' implies the filtering modes, but there is no explicit when-to-use-this-vs-list_items guidance and no when-not conditions. The agent must infer that variants are the inventory-keyed records rather than items.

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