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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and open-world behavior are covered. The description adds that prices are US-location scoped and lists the return contents (pharmacy price details, drug summary, priced prescription, location), which is useful but modest given the annotations already carry the behavioral profile.

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?

Purpose is front-loaded and the content is dense but relevant. It runs as one long semicolon-chained sentence, which is slightly harder to parse but contains no wasted filler.

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 detailed (though they are), and annotations cover safety. For a 9-param tool the description is nearly complete, with the only real gap being the unexplained state and zip_code location parameters.

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% across 9 params, so the description must compensate. It explains slug implicitly, covers label/form/dosage/quantity (defaults or from goodrx_drug_options) and latitude/longitude (US location pricing), but says nothing about the state and zip_code parameters, leaving two of nine undocumented in both places.

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 (Get) and a precisely scoped resource: GoodRx coupon, membership, and mail-order prices by pharmacy for one drug and prescription. It also enumerates what the response contains, so an agent can distinguish it from goodrx_drug_options, goodrx_drug_info, and goodrx_comparison without opening a 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?

Gives concrete routing guidance: omit label/form/dosage/quantity for GoodRx's default prescription or source them from goodrx_drug_options, and pass latitude/longitude to price at a specific US location. It names the sibling to pull parameters from but does not state explicit when-not-to-use conditions versus other pricing siblings.

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