food_lookup

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

The annotations already declare readOnlyHint and openWorldHint, so the read-only and external-data behavior is covered. The description adds the useful context that data comes from Open Food Facts, but it does not explain barcode-versus-query precedence, no-result behavior, or result variability beyond what openWorldHint implies. There is no contradiction with 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?

The description is a single front-loaded sentence with no filler. It states the scope, source, and lookup modes efficiently, which is appropriate for a small read-only lookup 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?

For a simple three-optional-parameter read-only tool with an output schema, the core facts are present. But the description is terse about query-versus-barcode behavior and gives no explicit usage guidance, so an agent would mostly be relying on inference. It is adequate but not fully 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?

The schema has 0% description coverage, so the description must compensate. It does map 'barcode' to barcode lookup and 'query' to name search, which adds real meaning. However, it does not describe the limit parameter or how query and barcode interact when both are provided, leaving part of the semantics to inference.

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 identifies a concrete resource (packaged-food information), a specific source (Open Food Facts), and the two lookup modes (barcode or name), so an agent can infer what the tool does. It lacks an explicit verb, relying on the tool name 'food_lookup' to convey the retrieval action, and it does not explicitly differentiate it from siblings like find_meals.

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 context is implied: an agent should use this when it needs packaged-food details from Open Food Facts, with barcode or name as the search route. However, the description gives no explicit when-to-use or when-not-to-use guidance, and it does not mention alternatives among the sibling tools.

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