compare_prices

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

The description reveals useful runtime behavior: return fields like observedAt and isLowest, the fact that the savings card may be relevant, and a caveat not to label a price as cheapest unless the offer says so. It does not discuss potential limitations like price recency or data availability, but the main behavior is well 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?

The description is focused and front-loaded with the core purpose, then gives output shape and usage cautions. A little dense, but every sentence adds operational value without repetition or 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?

The description tells the agent how to invoke the tool, what the output contains, and how to present results responsibly. It does not explain the optional locale and channel parameters, but the critical workflow context and output semantics are covered.

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?

Because schema descriptions are essentially absent, the tool description adds important meaning for ndc and quantity, including the 11-digit NDC format. However, it leaves the locale and channel parameters unexplained, and it only partially compensates for the missing schema descriptions.

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 clearly states the tool compares FineRx prices for a single package identified by an 11-digit NDC and quantity. It also distinguishes the appropriate precondition ('when you know the exact package') from other lookup flows, so the agent can decide between this and sibling tools.

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 explicitly says 'Use when you know the exact package' and tells the agent where to obtain an NDC if it does not already have one (get_drug's packages or the search flow). It also gives practical instructions about the savings card and how to report cheapest price, which helps correct invocation and response behavior.

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