Get a GoodRx head-to-head drug comparison by slug (for example lipitor-vs-zetia); returns the key takeaways and both drugs with price-page slugs. Use after goodrx_comparisons or goodrx_drug_info alternatives.
| Name | Required | Description | Default |
|---|---|---|---|
| slug | Yes | Comparison slug |
| Name | Required | Description | Default |
|---|---|---|---|
| data | Yes | The tool result payload (shape varies per tool; see each tool's docs resource). |
Changes observed during successful MCP inspections.
Input schema / properties / slug / descriptionAdded value: +"Comparison slug"Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and external-lookup behavior are covered. The description adds the return shape (key takeaways plus both drugs with price-page slugs) and slug format, but no auth, rate-limit, or failure context; with annotations doing the heavy lifting, a 3 is appropriate.
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 compact clauses that front-load the operation and then the follow-up routing hint; no filler. The second clause's phrasing ('or goodrx_drug_info alternatives') is slightly muddled but brief.
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 don't need full explanation, and the description still previews them. For a one-parameter read-only lookup with annotations present, the definition gives enough to invoke correctly, though the usage sentence could be sharper.
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% and the parameter is a single required 'slug' string, so the schema baseline would be 3. The description goes beyond it by giving a concrete slug example ('lipitor-vs-zetia'), which clarifies the expected format and disambiguates it from other GoodRx identifiers.
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 resource ('GoodRx head-to-head drug comparison by slug'), and the example slug (lipitor-vs-zetia) pins down the exact artifact. An agent can distinguish this from goodrx_comparisons (the list) and goodrx_drug_info (single-drug data) without opening either 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 names two related siblings ('Use after goodrx_comparisons or goodrx_drug_info alternatives'), which hints at a chained workflow for discovering the slug. However, 'after' and 'alternatives' are ambiguous — it never states clearly when to pick this tool versus those, nor any exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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