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

The readOnlyHint annotation already establishes this as a safe read operation, so the description's main burden is lifted. It adds only the API endpoint mapping, with no detail on pagination behavior, result shape, or rate limits beyond what the annotations and schema already convey.

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?

Two tight sentences with zero filler; the core purpose is front-loaded and the API hint trails it. Nothing could be cut without losing information.

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, zero-required-parameter list tool with a fully documented schema and no output schema, the description covers purpose, optional filtering, and the backing endpoint. Only minor detail (e.g., that results are paginated by default at 10/page) is absent, and the schema covers that.

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 four parameters (include, page_size, page_number, product_id) are already documented in the schema. The description reiterates the product_id filter but adds no syntax or format detail beyond it. 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?

Names a specific verb (List) and resource (variants), and clarifies the resource with a parenthetical definition ('price/plan tiers'), which helps an agent understand what a variant is. It also names the underlying API endpoint. It does not, however, distinguish itself from the closely related sibling lemonsqueezy_list_prices, which an agent could easily confuse with variants.

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 filtered to one product' gives a hint about the filter parameter's use, but there is no explicit statement of when to call this versus list_products, list_prices, or other list tools. Usage is implied rather than guided.

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