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

Annotations already declare readOnly, idempotent, non-destructive, so the safety bar is low. The description adds substantial behavioral context: the default returns the 50 lowest in the most-tested chemical, products below the lab's limit come first, and tested_total reveals the full count. That is real disclosure beyond the annotations.

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?

One dense sentence that front-loads the resource and the return contents, then folds the options into a compact trailing clause. No wasted words, though the single-sentence form is heavy to parse.

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?

With no output schema, the description carries the burden of explaining the return payload, and it does so well (typical levels, stand-in fidelity, product list, tested_total, default windowing). Combined with annotations covering the safety profile, an agent has enough to call it correctly.

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 baseline is 3. The description restates sort/order/all nearly as the schema does, adding only the nuance that the default sort chemical is the one tested in the most products. Marginal added value over structured fields.

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+resource: given a food category slug, it returns FDA's typical levels of metals and perchlorate plus the products with lab results in that category. The scope (FDA data, category-level contaminants) is clear enough to separate it from siblings like check_product or compare_products.

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?

Usage is implied through the category input and the examples (milk, rice, water), but there is no explicit when-to-use versus siblings such as compare_products or check_product, and no stated exclusions or prerequisites. The agent can infer intent but is not routed.

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