foreign_brands_for_drug

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

Annotations already mark the tool as read-only, idempotent, and non-destructive. The description adds substantial useful behavior beyond that: returned fields, the special meaning of rx_alternative as a different medicine, the guarantee that brands with no US equivalent never appear, and explicit cautions against presenting interchangeability or advising purchases/imports.

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?

Every sentence carries distinct information: purpose, usage, output fields, ordering guidance, and safety guardrails. The key purpose and usage are front-loaded, and the cautions are placed after the functional details where they are most relevant.

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 single-parameter read-only tool with an output schema and rich annotations, the description covers everything an agent needs: source of the input, expected output, result interpretation, ordering preference, and limitations. No critical gap remains.

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%, so the description must compensate for the bare string parameter. It does this well by explaining that slug comes from search_drugs and illustrating with a user-phrased question, which tells the agent where to source the value. It stops short of defining the exact slug format, so a 4 is appropriate rather than a 5.

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 first sentence declares a specific verb and resource: 'Find what a US drug is called abroad,' and explicitly contrasts it with the sibling find_us_equivalent. This makes the tool's scope immediately distinguishable from related tools without needing to inspect schemas.

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?

The description gives concrete when-to-use guidance with a realistic user example ('what is lisinopril called in Mexico?') and states that slug comes from search_drugs. It also names the reverse sibling, allowing an agent to route between them correctly.

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