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

With readOnlyHint and idempotentHint already present, the description adds behavioral context by explaining the pagination-focused use case and that the tool is device-specific. It also notes that fda_get_facility includes products, which helps the agent understand data overlap and avoid redundant calls. No contradictions.

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 front-loaded with the core purpose and return value specifics, and it is four sentences long. The final 'Requires: FEI number' is redundant with the schema, costing some conciseness, but overall the description is efficient.

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 tool is simple, the schema fully documents parameters, and the description lists the return fields and provides usage context pointing to related tools. The absence of an output schema is compensated by the explicit field list, making the description complete for its complexity.

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 the schema already documents all three parameters. The description mentions pagination and the FEI requirement but adds no parameter-specific details beyond what the schema provides, meeting the baseline for full coverage.

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 uses the specific verb 'List' and identifies the resource as 'device products registered at a facility by FEI number'. It also names the returned fields and explicitly distinguishes this from fda_get_facility, which already includes products, making the tool's niche clear.

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 states 'use this only when paginating through large product lists', providing an explicit condition for use. It also gives an alternative for drug products: 'use fda_search_ndc with company name instead', covering both device vs drug contexts.

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