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

The description goes well beyond the readOnlyHint/idempotentHint annotations by describing the exact result set ('reviewed brands'), listing returned fields, and stating that brands with no US equivalent never appear. It also discloses important safety behaviors: do not present these as interchangeable and do not tell anyone to buy or import one. No contradiction with annotations.

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 organized into focused, front-loaded sections: purpose and use cases first, then parameter provenance, then return fields and clinical safety guidance. There is no filler, and the added length is justified by the medical safety context.

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 covers purpose, when to use the tool, how to obtain the required slug, the returned fields, and important exclusions and safety constraints. Since the output schema exists, the description does not need to restate return shapes, and nothing needed to invoke the tool correctly is missing.

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?

The schema only defines slug as a required string with no description. The description adds crucial meaning by stating that 'slug comes from search_drugs', telling an agent exactly how to obtain the correct value. With only one parameter this is sufficient, though the description does not independently define the slug format.

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 opens with a specific verb and resource: 'Find what a US drug is called abroad' and explicitly names the inverse sibling tool, find_us_equivalent. This immediately establishes what the tool does and how it differs from the most similar alternative.

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 gives concrete conditions for use: when the person has the US name and wants the home-country name, or when a foreign brand would help recognition. It also tells the agent to prioritize brands from the person's own country, clarifies that rx_alternative is a different medicine, and warns against presenting the brands as interchangeable.

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