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

Annotations already establish that this is a read-only, open-world lookup. The description adds meaningful behavioral context beyond the annotations: pricing at $0.002 USDC per successful call, payment via x402 on Base/Solana/Arc, and the fact that failed calls are not charged.

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 definition is dense but front-loads the core purpose and regulatory scope before the pricing detail. The long first sentence is justified by the complexity of the regulatory coverage, and the pricing sentence is short and useful.

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?

Given the output schema and annotations, the description provides a complete enough picture: what is looked up, which regulatory annexes are covered, what fields are returned, and how billing works. The main remaining gap is sibling differentiation, which is a minor omission for a read-only lookup tool.

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 description coverage is 100%, so both parameters are already documented in the schema. The description reinforces that the lookup is by substance name and describes the regulatory entries returned, but it does not add syntax or constraints beyond what the schema provides; baseline 3 is appropriate.

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 states a specific resource and scope: EU cosmetics regulatory status from CosIng, including the exact annexes and Regulation (EC) No 1223/2009. It is clear what the tool returns, but it does not explicitly distinguish itself from the sibling health_cosmetics_inci_ingredients tool.

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?

There is no explicit guidance on when to use this tool versus alternatives, nor any stated prerequisites or exclusions. The use case is implied by the description of regulatory status lookup, but the agent is left to infer when this is preferable to the related cosmetics INCI tool.

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