fda_unii

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

Annotations already declare readOnlyHint=true, and the description does not contradict this. The description adds value by explaining the domain (ingredient identifiers) and providing example query syntax, which goes beyond the annotation. It does not disclose return format or pagination behavior, but for a read-only search tool with annotations, this is acceptable.

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: a one-sentence purpose followed by two illustrative examples. No fluff; every line adds value. It is front-loaded with the core purpose.

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 (2 optional params, full schema coverage, read-only annotation, no output schema), the description is largely complete. It provides query examples and the concept of UNII. A mention of result structure or pagination could improve it, but it's not strictly necessary for this tool's complexity.

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 100%, so baseline is 3. The description adds concrete query syntax examples ('unii:"L7V4I673D2"' and 'substance_name:"ASPIRIN"') that are not present in the schema, demonstrating how to use the search parameter effectively. This exceeds the baseline.

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 searches UNII (Unique Ingredient Identifiers) and links ingredient names to chemical IDs. The verb 'Search' plus the resource 'UNII' makes the purpose specific. It doesn't explicitly distinguish from sibling FDA tools like fda_substance, so it doesn't earn a 5.

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?

Example searches provide clear usage context for querying by UNII code or substance name. However, the description does not mention when to prefer this tool over other similar FDA tools (e.g., fda_substance), nor does it provide any exclusions or alternative guidance.

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