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

Annotations only declare readOnlyHint and openWorldHint; the description adds genuinely new behavior: a $0.002 USDC charge per successful call via x402 on Base/Solana/Arc, no charge on failure, and a hard 10-result ceiling. That cost and failure-billing detail is exactly the kind of context annotations cannot convey, though it says nothing about pagination or ordering of results.

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?

Three sentences, front-loaded with what is returned and immediately followed by the scope exclusion, then limits and pricing. Dense but every sentence carries information; the pricing sentence is long but necessary for a paid tool.

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?

An output schema exists, yet the description still summarizes the return shape, and it covers the two things an agent most needs for a paid, capped lookup: the per-call cost and the 10-result limit. Nothing material is missing for correct invocation.

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 both parameters are already documented, and the description only restates the 10-label ceiling already present in the 'max' schema. Baseline 3 applies since the description adds no new meaning about drug-name matching behavior (e.g., exact vs. partial match).

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 ('NLM DailyMed drug label listings ... matching a drug name') and enumerates the returned fields (title with labeler, set ID, label version, published date, total match count). The clause 'Lists labels only; label section text is not included' draws a clear boundary that separates it from any full-label-text or drug-interaction sibling.

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 'lists labels only, no section text' note implies the right context of use, and the 10-per-call cap signals a discovery-style lookup. However, no sibling is named as an alternative and there is no explicit when-to-use or when-not-to-use statement, so routing is left partly to inference.

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