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

Annotations already declare readOnlyHint=true and openWorldHint=true. The description adds real behavioral context beyond that: the data originates from a separate dedicated ingredients page, and some products (especially non-consumables) return empty ingredient fields rather than an error — a useful failure-mode disclosure.

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 resource and return fields, followed by sourcing, scope, and slug format. Slightly dense — the parenthetical about Drug Facts purpose notes and the long slug example add length — but every sentence contributes.

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?

With an output schema present, the description needn't detail return shape, yet it names the returned ingredient fields, the catalog scope, the slug input format, and the empty-result edge case. Nothing needed 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 0%, so the description must carry the parameter, and it does fully: it defines slug as the URL segment after /shop/, gives a concrete example, and notes that a full https://www.cvs.com/shop/... URL is also accepted.

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 — retrieving one CVS.com OTC product's ingredient/label statement — and enumerates the returned fields (active, inactive, free-text paragraph). It explicitly separates itself from the sibling cvs_product by noting the data comes from a dedicated ingredients page rather than the product record.

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?

Clear context: it scopes usage to the non-prescription retail catalog and contrasts with cvs_product's data. It stops short of an explicit when-to-use/when-not rule or naming the sibling as the alternative to call instead, but the routing is unambiguous.

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