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

Goes well beyond the readOnly/openWorld annotations by disclosing the data source (openFDA GUDID copy), fallback behavior (FDA AccessGUDID), pricing ($0.002 USDC per successful call via x402 on Base/Solana/Arc), and that failed calls are not charged. These are material operational details an agent needs before invoking a paid API.

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-loads the core lookup purpose and returned fields, then adds source/fallback, lookup constraint, and pricing in short, purposeful sentences. Dense but every sentence contributes necessary 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?

Complete for a single-parameter lookup tool: it explains the identifier, the record fields, data sources and fallback, lookup limitation, and payment model. An output schema exists, so the description does not need to detail the response shape further.

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 coverage is 100% and already documents that di is an 8–14 digit string. The description adds useful semantic context by identifying it as the GS1/GUDID number on a device label, which helps an agent map real-world input to the parameter.

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: retrieve an FDA GUDID device record by Device Identifier. The included field list (brand, company, model, GMDN term, MRI safety, single-use/prescription flags) makes the record type concrete and distinguishable from adjacent device tools like 510(k) or recalls.

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?

Explicitly constrains usage to DI lookup and says 'no name search,' which tells the agent when not to use it. However, it does not name a specific alternative sibling for name-based device searches, so the routing guidance is clear but not fully complete.

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