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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is clear. The description adds valuable context beyond annotations: it discloses the pricing model ($0.002 USDC per successful call via x402, failed calls not charged) and the data source ('FDA's monthly Purple Book data download'), which helps an agent understand cost and data freshness. Minor gaps remain around matching semantics (exact vs. partial) and error behavior, but the added context is substantial.

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 is generally well-structured. However, it enumerates many return fields ('applicant, BLA number, license type... exclusivity expiry dates') that are already documented in the output schema, making it longer than necessary. The pricing sentence is useful but the overall paragraph could be tighter given the structured fields available.

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 read-only tool with two parameters and a full output schema, the description covers the essential context: what data is returned, where it comes from, and the cost model. It does not explain matching behavior (exact vs. partial name matching) or handle formatting for the 'name' parameter beyond an example, but these are minor gaps given the annotations and output schema already provide safety and return structure.

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 both parameters ('name' and 'limit') with types and constraints. The description adds an example ('adalimumab') and clarifies that 'name' can be a brand, proper name, or BLA number, but this largely restates the schema. With full schema coverage, 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 verb and resource: 'FDA Purple Book licensed biological products matching a name'. It enumerates the exact fields returned (applicant, BLA number, license type, etc.), which clearly distinguishes it from siblings like health_fda_orange_book (drugs) and health_fda_adverse_events_faers. An agent can immediately tell this is for biological product licensing data.

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 implies usage by saying 'matching a name (brand or proper name, e.g. adalimumab)', but it never states when to use this tool versus alternatives such as health_fda_orange_book or health_ema_human_medicines. There are no explicit exclusions or alternative-routing instructions, leaving the agent to infer the appropriate context.

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