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

Annotations already establish read-only, idempotent, non-destructive behavior, and the description adds useful output semantics: 'Returns each match with its INS number, name, synonyms, technological functional classes, and how many food-category provisions it holds.' This goes beyond the annotations by clarifying what the agent can expect in the response, though it does not discuss potential partial matches or limit behavior.

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, each with a distinct purpose: the action and search keys, the return fields, and the recommended usage workflow. No filler, and the most important information is front-loaded.

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 simple two-parameter tool with no output schema and full annotations, the description covers what the tool does, what it returns, and when to use it. It even names the searchable fields and the output fields, so an agent can confidently invoke it without needing the schema.

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% for both query and limit, so baseline is 3. The description largely restates the schema's query semantics ('INS number, additive name, or synonym') and adds only a slight clarification by mentioning 'E-number' in the usage sentence. No meaningful extra parameter nuance is provided.

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 action ('Find food additives in the Codex GSFA by INS number, name, or synonym') and lists the return fields, which clearly distinguishes this additive search tool from sibling tools like gsfa_search_food_categories and gsfa_additive_provisions.

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 gives explicit usage context: 'Use to resolve an additive name or E-number to its GSFA entry before looking up permitted uses.' It does not name alternative tools or specify when not to use, so it falls short of a full 5, but the workflow guidance is clear.

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