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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false. The description adds meaningful traits: live price/availability fetching vs indexed snapshot fallback, explicit indication when snapshot is used, and handling of unknown ids as not_found. This goes beyond the annotation baseline.

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?

Three sentences, front-loaded with the core purpose and id format. Every sentence adds value, with no fluff or repetition.

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?

The tool has nested objects and many optional parameters, and no output schema. The description covers only ids and source behavior, leaving the purpose of context, filters, and other fields unexplained. An agent would lack confidence in how to populate those optional parameters correctly.

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 must compensate. It explains the ids parameter and its format, but completely ignores the meta, context, filters, signals, and attribution fields. The schema has no inline descriptions, so agents won't know their purpose without additional documentation.

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 (lookup), resource (products/variants by identifier), and scope (up to 25 ids) with exact id format examples. This distinguishes it clearly from siblings like get_product (single item) and search_catalog (query-based).

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?

Implies usage context: for direct id-based lookups rather than searching or fetching a single product. Mentions live vs snapshot behavior but does not explicitly contrast with sibling tools; however, the id-based nature makes the intended scenario clear.

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