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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral detail by stating the output includes class IDs, names, and classification sources, which goes beyond the annotation metadata without contradicting it.

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?

The description is compact and well-structured: a one-sentence summary, a short bulleted list of use cases, and a one-line output summary. No redundant or filler content is present, and the key purpose is front-loaded.

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 a single documented parameter, rich annotations covering safety and idempotency, and an output schema, so the description's brief mention of return contents is sufficient. There are no hidden prerequisites, complex flags, or pagination concerns that would demand additional explanation.

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?

There is only one parameter, rxcui, and the schema itself already describes it as the 'RxCUI of the drug' with a validation pattern, so schema coverage is 100%. The description does not add extra parameter-level meaning beyond the schema, which makes the baseline 3 appropriate.

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?

The description opens with a specific verb and resource: 'Get therapeutic and pharmacologic classes for a drug.' It gives concrete examples (Beta-blockers, NSAIDs) and clarifies the tool returns class IDs, names, and sources. This clearly distinguishes it from sibling RxNorm tools like rxnorm_concept or rxnorm_ingredients.

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?

The 'Use this tool to' section lists concrete use cases: finding drug classes, therapeutic categories, and mechanism-of-action classifications. It does not explicitly name sibling alternatives or state when not to use it, so it misses the full when/when-not guidance, but the provided context is clear and actionable.

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