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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds genuinely useful behavioral context beyond them: the data comes from a separate ingredients page, and some products (particularly non-consumable goods) return empty ingredient fields rather than an error — a failure mode the agent must anticipate.

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?

Four sentences, each carrying distinct payload (what is returned, source, scope, argument format + edge case), with the core payload front-loaded. Slightly dense but no sentence is filler, so it stays well within budget for a single-parameter read tool.

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 no further explanation, and the description still covers everything else an agent needs: scope, provenance, argument format, and the empty-result edge case. Nothing material is missing for calling this tool 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 coverage is 100% but the schema's own slug description is truncated ('CVS product page URL slug, e.g. \'), so the schema alone is unhelpful. The description compensates by defining the slug as the URL segment after '/shop/' with a concrete example and by noting 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 precise verb+resource: retrieves one CVS.com OTC product's ingredient/label statement, enumerating the three component pieces (active ingredients, inactive ingredients, vendor free-text paragraph). It explicitly separates itself from the sibling cvs_product ('separate from cvs_product's own data'), so an agent can choose between them 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?

Scope limits are stated clearly: non-prescription OTC retail catalog only, sourced from the dedicated ingredients page rather than the general product record. It stops short of explicitly naming when to prefer this tool over cvs_product (e.g. 'use cvs_product for price/name'), so the routing is implied rather than spelled out.

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