ATC Classification for a Drug

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

Annotations already cover readOnlyHint, idempotentHint, and destructiveHint, so the description does not need to repeat safety. It adds valuable behavioral details: returns one entry per ATC code, combination products map to multiple, and it retrieves data via NLM RxClass. This goes beyond the annotations and enriches the agent's understanding of the response behavior.

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 concise and well-structured: an opening statement, a bulleted list of use cases, and a brief paragraph on return behavior and data source. Every sentence contributes meaningful information without redundancy, making it efficient and easy to scan.

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 the tool's simplicity (1 parameter, output schema present, non-destructive annotations), the description is fully complete. It covers purpose, usage, return behavior, and data source. No critical context is missing for an agent to select and invoke the 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?

The input schema already provides a description for drug_name ('brand or generic, e.g., "metformin"') and schema coverage is 100%, so the baseline is 3. The description adds a concrete example in context but does not introduce new parameter semantics beyond the schema. It does not compensate for any missing parameter details.

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 clearly states the tool's purpose: 'Look up the WHO ATC classification(s) for a drug by name.' It provides specific use cases and examples (e.g., metformin → A10BA02), making the verb and resource clear. However, it does not explicitly distinguish from sibling tools like atc_lookup or atc_members, so it misses the top score for sibling differentiation.

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 description provides clear use context with a bulleted list of when to use the tool (find ATC code, identify hierarchy, cross-reference drugs). It does not, however, mention any exclusions or alternatives, such as when to use atc_lookup instead. This is clear context without explicit when-not-to-use guidance.

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