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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds value beyond that: it discloses that the call can return multiple candidate entries requiring disambiguation by strength/form, and that the RxCUI it yields is consumed by check_coverage. It stops short of describing empty/no-match behavior or the full result shape.

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 sentences, zero filler, and the front-loaded sentence carries the purpose plus the downstream dependency. The second sentence earns its place by telling the agent how to choose among results.

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 single-parameter read tool with no output schema, the description covers purpose, return value (RxCUI), and the ambiguity an agent must resolve. Minor gap: no hint about what a no-match or overly broad query returns.

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 coverage is 100% with a worked example ("metformin" or "Ozempic"), so the baseline is 3. The description reinforces that either generic or brand names are accepted, which is a marginal addition over a schema whose examples already demonstrate exactly that; the minLength of 3 is not mentioned.

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?

States a specific verb and resource ("look up a medication by name"), names both accepted name types (generic or brand), and states the output that matters (RxCUI). It also distinguishes itself from the sibling by explaining the downstream hand-off to check_coverage, so an agent knows this is the entry point of a two-step flow.

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?

Clear context: use this before check_coverage, and "Pick the entry matching the strength and form the person takes" tells the agent how to resolve multiple hits. No explicit when-not or excluded case, but none of the siblings (check_coverage, get_plan, search_doctors, search_plans) are competing drug searches, so no alternative needs naming.

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