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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds a genuinely useful domain fact not present in any structured field: variant ids are the key inventory levels are stored against, which tells the agent how this tool chains into loyverse_list_inventory and loyverse_set_inventory_levels. It stops short of describing pagination or return shape.

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?

Front-loaded with purpose, then the disambiguation, then the underlying endpoint. Three short units with no redundancy. The 'Loyverse: GET /variants' tail is minor but defensible for an API-mirroring toolset.

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 10-parameter, all-optional list tool with annotations covering the safety profile, the description covers selection well. With no output schema present, a sentence about what a returned variant record contains would close the remaining gap.

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% across all 10 parameters, so the schema already carries the semantics. The description only alludes to the items_ids/sku filters generically and adds no format, default, or interaction detail beyond the schema. Baseline 3 applies when the schema does the heavy lifting.

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?

States a specific verb and resource (list item variants) and immediately disambiguates the domain term: variants are the sellable SKUs, distinct from the parent items covered by loyverse_list_items. The agent can tell what this returns without opening the schema.

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?

It implies the two filtering modes ('optionally for given items or one SKU'), which maps to items_ids and sku, but never states when to reach for this over loyverse_list_items or loyverse_list_inventory, and gives no exclusions or prerequisites. Usage is inferable but not spelled out.

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