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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuine behavioral context beyond that: the 20-part batch cap, that unrecognized part numbers surface in not_found, and that group filters the returned attribute set. It does not describe response shape, but an output schema exists.

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 the core purpose and densely packed with useful clauses; almost every phrase (attribute list, sibling exclusions, group semantics, not_found) earns its place. It is on the long side and slightly list-heavy, which keeps it just under top marks.

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 an output schema exists, the description need not explain return values, and it covers everything else an agent needs: scope, batch limit, sibling routing, group filtering, and the not_found error case. Nothing required to call it correctly is missing.

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% and the schema already documents both parameters in detail, including the group enum values and the part_number cross-references to sibling tools. The description largely restates this, adding only the note that part_numbers maps to the same identifiers returned by other tools. Baseline 3 is correct 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+resource+scope ('Chewy's own specification table for up to 20 products in one call, keyed by part number') and enumerates exactly which attributes it returns (lifestage, pet type, handling/compliance flags, bundle structure, autoship, category group ids). It also explicitly distinguishes itself from chewy_products and chewy_product, so an agent can pick it without opening schemas.

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?

Explicitly routes: 'Complements rather than repeats chewy_products and chewy_product -- price, rating, images, reviews and descriptions stay on those, and the attribute table is on neither.' It also states when to use the group parameter and what happens on unrecognized input. The boundary between this tool and its siblings is unambiguous.

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