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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint false, so the safety profile is covered. The description adds value beyond those annotations by specifying the 137,000+ marketed-product scope, enumerating result fields, and providing Lucene filter syntax. It also notes the data source is US public domain, which is useful trust/context. No contradiction with annotations.

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 front-loaded: the first sentence names the tool and its scope, the second enumerates returns, the third gives query examples, and the fourth states use cases. The final source note is brief and earns its place by adding provenance. No filler or redundant restatement of the title or annotations.

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 no required parameters, a complete schema, and an output schema that covers the return structure. The description supplies the missing contextual pieces: scale, available fields, query syntax examples, common use cases, and data source. Nothing essential is missing for an agent to select and invoke 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 description coverage is 100%, so the schema already documents all three parameters well. The description adds concrete Lucene examples (generic_name:"ibuprofen", product_ndc:"0069-2587", AND-combined fields) that clarify how the search parameter should be formatted, going beyond the schema text. Pagination parameters are adequately handled by their schema descriptions.

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 the specific verb 'Search' and names the exact resource: the FDA National Drug Code Directory. It lists concrete returned fields (NDC, generic/brand name, labeler, active ingredients, dosage form, route, marketing category, pharm class, DEA schedule), making the tool's purpose unmistakable and clearly distinct from safety/recall siblings such as fda_openfda.safety.drug_recalls.

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 gives clear usage context by stating the tool is 'useful for drug identification, manufacturer lookup, and dosage-form/ingredient research by NDC code or name.' It does not explicitly name alternatives or exclusion conditions, but the stated use cases and 'reference directory' framing provide enough orientation for an agent to select it over recall/event tools.

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