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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds useful output context (lowest displayed price, summary, price-page slug), but because an output schema already exists, this return summary is largely redundant and no auth, rate-limit, or pagination behavior is disclosed.

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?

A single front-loaded sentence states the action, its input provenance, and the returned fields with no wasted words. Nothing could be removed without losing information.

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 one-parameter, read-only tool with an output schema, the description covers purpose, input provenance, and a return summary, which is everything the agent needs. The output schema carries the detailed return structure, so nothing material is missing.

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 0% and the single 'slug' parameter is a bare string, so the description must carry the semantics. It does this well by specifying the slug is a drug class slug sourced from goodrx_classes, though it gives no format example.

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 gives a specific verb (List) and resource (the drugs for one drug class), and it explicitly ties the input to goodrx_classes, distinguishing this singular-class tool from the plural goodrx_classes lister. An agent can tell it apart from siblings without opening the schema.

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 establishes clear prerequisite context by stating the slug must come from goodrx_classes, which effectively routes the agent through the right workflow. It stops short of naming when-not-to-use or a specific alternative tool to call instead, so it is clear context without exclusions.

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