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

Annotations already declare the full safety profile (readOnly, idempotent, openWorld, non-destructive), so the description doesn't need to restate it. It adds genuine value by listing the label content returned (indications, dosage, warnings, contraindications, mechanism, manufacturer, DEA scheduling), which is important since no output schema exists. It omits behavior like multiple-match handling or error cases, hence not a 5.

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?

Two tight sentences with the core capability front-loaded and the return fields enumerated. The trailing 'Used for...' sentence is the weakest element, leaning toward audience framing rather than actionable instruction, but it is short and does not bloat the definition.

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?

For a read-only lookup with 100% schema coverage and no output schema, the description supplies the return-field inventory an agent needs and the accepted identifier forms. Minor gaps remain: behavior on ambiguous matches, label-version selection, and how the limit interacts with results are unaddressed.

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% and both parameters are documented with examples in the schema itself. The description restates the three accepted query forms but adds no syntax, format, or edge-case detail beyond the schema, so the baseline 3 applies.

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 pairs a specific verb ('Look up') with a precisely scoped resource ('FDA drug label info') and enumerates the identifier forms (NDC, brand, generic) plus the fields returned. That field list makes the resource unambiguous against neighbors such as fda_drug_adverse_events and fda_drug_recalls, which cover different FDA drug data.

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?

It gives audience-oriented context ('clinical decision support, pharmacy automation, drug-info chatbots') but never states when to pick this tool over alternatives, nor any exclusions or prerequisites. Usage is implied rather than directed.

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