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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds useful behavior beyond that: it enumerates the pricing types returned (coupon, membership, mail-order), which parameters are optional-by-default, and that a US location constrains pricing. It stops short of noting freshness, coverage, or rate limits.

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, purpose front-loaded before the operational guidance, with little waste. The return-value enumeration in the first sentence is somewhat redundant against the existing output schema, which is the main thing keeping it from a 5.

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 9-parameter tool with only one required field and an existing output schema, the description is mostly complete: it explains the default behavior, the parameter sourcing, and the location option. It does not cover what happens if location inputs are omitted entirely or how prices vary, minor gaps given the output schema exists.

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%, so the baseline is 3, but the description adds real meaning the schema does not: it clarifies that label/form/dosage/quantity can be omitted to fall back to GoodRx's default prescription and where to source them otherwise, and that lat/long must be supplied together for location pricing. That cross-parameter relationship is more than the schema conveys.

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 precise resource (GoodRx coupon, membership, and mail-order prices by pharmacy for one drug and prescription), and it references the sibling tool goodrx_drug_options so the agent can distinguish it from adjacent GoodRx tools. The scope of what is priced (one drug + prescription) is explicit.

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 actionable routing guidance: omit label/form/dosage/quantity for the default prescription or take them from goodrx_drug_options, and pass latitude/longitude to price at a specific US location. It names the alternative source of parameter values clearly, though it does not state explicit when-not-to-use conditions or contrast with pricing siblings like goodrx_comparison.

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