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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context beyond annotations: it returns full detail and includes recalls that reference the clearance, which is meaningful for an agent deciding between this and search_recalls.

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?

A single sentence that front-loads the primary purpose and then adds the recall-related behavior. Every word earns its place, with no padding or redundancy.

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 one-parameter, read-only lookup, the description covers the main behavior and return scope well. It does not specify behavior for an unknown K-number, but given the simple fetch-by-ID nature and existing annotations, this is a minor gap rather than a blocking omission.

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%, and the schema already identifies k_number as the required identifier with an example. The tool description merely repeats 'by K-number' without adding new format, validation, or usage semantics, so the baseline 3 applies.

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 clearly states a specific verb/resource pair: retrieving full detail for one FDA 510(k) clearance by K-number. It also adds a distinguishing scope detail—including related recalls—so it is identifiable against sibling search and stats tools.

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 clear context: use this when you need complete detail for a single clearance identified by K-number. It does not explicitly name alternatives or exclusion cases, but the contrast with search-oriented siblings is reasonably clear from 'full detail for one'.

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