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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful non-schema context — that calls are free within a daily allowance and cost $0.003 USDC per call via x402 — but says nothing about result ordering, pagination, or query 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?

Two short sentences with no filler; the resource is front-loaded before the pricing detail. It is efficient, though the second sentence covers cost rather than usage, so brevity comes partly at the expense of usefulness.

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?

An output schema exists, so return values need not be described. Still, the tool's required parameter is a free-form 'openFDA search expression' with no syntax example or common field references (drug name, classification, report date), which is the main thing an agent needs to invoke it 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%, with both parameters documented (search expression, limit default 10/max 100), so the baseline is 3. The description adds no syntax hints for the openFDA search expression or interaction with limit, so it does not exceed the schema.

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 states a specific resource (drug recall enforcement reports) and the domain word 'Drug' distinguishes it from the device-recalls and food-recalls siblings. However, it uses no verb and gives no sense of what the tool returns or how results are shaped, so it is clear but not fully differentiated in action terms.

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?

There is no guidance on when to use this tool versus related siblings such as openfda__drug-adverse-events, openfda__drug-labels, or openfda__device-recalls. The only conditional statement is about billing, not about selecting this tool for a task.

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