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

Goes well beyond the annotations: it explains why destructiveHint is true (list fields are replaced whole; `variants: []` removes variants), states that the tool is a partial update so unspecified fields survive, and discloses precondition failure behavior — a store-backed product is rejected and the answer says so. This is exactly the context an agent needs before a destructive write.

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 and object, with the critical preconditions in the middle and the id hint last — a logical order. The parenthetical asides and dash clauses pack a lot per sentence and reward a careful second read, so it is dense rather than wasteful.

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?

Given nested objects, destructive semantics, and an existing output schema, the description covers everything an agent needs: which products qualify, what gets overwritten, how to do a partial update, how variants are cleared, and how to supply the id. Return values are correctly left to the output schema.

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%, so the baseline is 3, but the description adds real meaning: `productId` accepts either the id that search_products reports or the sku, and `fields` should contain only the delta rather than a full object. It doesn't add cardinality or validation detail beyond the schema, which already documents options/variants replacement.

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 ("Change a product the merchant keeps in Foldsquare") and enumerates exactly which attributes are editable, so the scope is unambiguous. It also names what it is not: store-sourced products edited in the store or via edit_catalog's editProduct, distinguishing it from the two nearest siblings.

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?

Explicit when-to-use (merchant-kept products, imported or hand-added), when-not (products originating from the connected store), and the alternatives (the store itself, or edit_catalog's editProduct per catalog). It also gives the partial-update rule, "Give only the fields to change," which is the key calling convention.

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