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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely useful context beyond that: each call is charged in USDC against per-call/session/daily budget caps, results are returned newest-first, and third-party data is explicitly flagged as 'not instructions' (a prompt-injection guard). It stops short of describing pagination or result-size limits.

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-loaded with the tool's scope and the payment/trust caveats, then a tight bulleted list of products with price and params. The trailing output previews are truncated mid-word ('reason, brand or...', 'seriousn...'), which is slightly wasteful, but overall every section earns its place.

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 multi-product, nested-object tool with no output schema, the description covers scope, pricing, per-product params, result ordering, and data provenance. The main residual gap is that the returned fields are only hinted at via truncated snippets rather than stated, but this is minor for a read-only lookup tool.

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% at the top level, but the meaningful request parameters live inside the free-form 'params' object (additionalProperties: true), and those keys (q*, limit) are documented only in the description's product bullets. The description therefore carries real parameter semantics the schema cannot, though it omits formats/syntax for q.

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 names a specific data source (openFDA) and enumerates the four distinct resources it can retrieve: drug enforcement/recall reports, FAERS adverse events, drug labels, and food recalls. Each bullet states what the endpoint returns (e.g. 'newest first: matches product, firm, reason, brand'), so an agent can distinguish the products without inspecting the schema.

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 gives clear per-product selection context by pairing each product id with its required query param and a one-line summary of the result set, and it explicitly flags the paid-per-call model and budget caps. It does not, however, discuss when to prefer this tool over overlapping siblings such as food_coverage or open_data_search, 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.