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

Annotations cover the safety profile (destructiveHint=true, openWorldHint=true), and the description adds real behavioral detail beyond them: pricing_type is forced to one_time for physical products, and unknown variant ids are rejected. It still does not describe reversibility or side effects on downstream billing, but the added domain rules are meaningful.

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 core rule and unit convention ('2999 is $29.99') are front-loaded, followed by a scannable Args block. Slight redundancy in restating parameter names, but that repetition is justified given zero schema-level descriptions.

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?

An output schema exists, so return values need not be explained, and all seven parameters are accounted for. The remaining gap is the absence of any cross-reference to the variant/product update siblings an agent must choose between.

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 0%, so the description carries the full burden and does so: every parameter is documented, including sentinel semantics (-1 keeps current, 0 clears compare-at), currency format, the pricing_type value set, and a concrete variant_prices JSON example. This is well beyond what the bare 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?

The description opens with a specific verb and resource: 'Set product and/or per-variant pricing in one call.' That clearly distinguishes it from the create/delete siblings. It does not explicitly differentiate itself from update_commerce_variant, which also touches variant pricing, so it falls short of a 5.

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 states an important precondition ('At least one pricing argument must be supplied'), which is genuine usage guidance. However, it never says when to use this tool versus update_commerce_product or update_commerce_variant, leaving the agent to infer boundaries between near-identical siblings.

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