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

Annotations already declare readOnly, idempotent, non-destructive, open-world behavior. The description adds genuinely non-structured context: results come from the normalized official NMPA UDI dataset, this is exact (not fuzzy) lookup, and UDI presence is not proof of safety or legal sale. It does not describe pagination/result-size behavior, keeping it short of a 5.

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?

Front-loaded with the use trigger, then scope exclusions, then input format and a caveat. Every sentence contributes, though the caveat and the example add length that could be trimmed in a tighter definition.

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?

No output schema exists, so the description carries the return-value burden and does list the record fields (product, model, registrant, registration number, publication date). Pagination parameters exist but their use is only implied, leaving a small gap.

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 only 25%; only snapshot is documented in the schema. The description compensates for the required udi parameter (input as string, preserve leading zeroes, example value), but says nothing about limit or offset, so pagination semantics remain undocumented. Baseline 3 fits given the low coverage and partial compensation.

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 and resource (lookup China NMPA device by UDI/DI/GTIN) and enumerates the returned fields. It explicitly carves out what it is not (not full barcode parsing, not a global GTIN directory), which separates it from the search_* siblings.

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?

"Use whenever the user provides a UDI, DI, GTIN or exact device identifier" and "Prefer this tool before general web search" give clear triggering conditions. It does not explicitly route to sibling tools like search_china_medical_device for fuzzy or partial matches, so the alternative guidance is partial.

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