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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false. The description adds valuable behavior beyond that: it discloses what the call returns, including GMP limits, the source GSFA table, conditioning note references, and whether the permission was inherited from a parent category. It does not contradict the annotations, and no destructive side effects are implied.

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 question and then lists the returned fields and use cases efficiently. There is slight redundancy between 'at what maximum level' and 'Returns the maximum use level,' but every sentence otherwise 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?

Because there is no output schema, the description compensates well by enumerating the important return elements: maximum level, GMP possibility, source table, note references, and inheritance status. With two fully documented required parameters, this is sufficient for correct invocation, although explicit sibling-tool differentiation would make it more complete.

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 the schema already explains that additive accepts INS numbers, names, or synonyms and that food_category accepts category numbers, names, or parent categories. The description adds general context about GSFA maximum-use values but does not materially deepen the meaning of the two parameters beyond the schema.

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 uses a specific verb and resource: it 'answer[s] whether a specific food additive is permitted in a specific food category' under the Codex GSFA, and states the returned maximum level. It distinguishes itself from the many GSFA sibling tools by focusing on the exact additive-category pair plus provenance details like table, notes, and inherited permissions.

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 explicitly states use cases: 'questions about whether an additive is allowed in a food, legal use levels, and food additive compliance.' However, it does not name alternatives or say when not to use this tool, such as when the user wants all additives in a category or all categories for one additive.

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