List Portions

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

Annotations already provide readOnlyHint and idempotentHint, so safety is covered. The description adds the nuance that gram weights are returned 'when available', which is useful but minimal. No extra details about output structure or edge cases, though an output schema exists.

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, focused sentence that front-loads the action and resource. No filler or redundant information; every word 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 simple read-only tool with one parameter, an output schema, and strong annotations, the description is complete. It covers the core behavior and uses the output schema to handle return structure, requiring no further elaboration.

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 0% and the schema only lists fdcId with a type. The description implicitly explains that fdcId identifies a FoodData Central entry, giving meaning to the parameter. This is sufficient for a single-parameter tool, though not explicitly naming the parameter.

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 clearly states the tool's action ('Return') and resource ('labeled portion sizes for a FoodData Central entry'), with a specific qualifier ('including gram weights when available'). This is distinct from sibling tools that handle foods, nutrients, or categories, as it focuses specifically on portion sizes.

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 implies the tool is used when you have an fdcId and need portion sizes, but it does not explicitly mention alternative tools (e.g., macros_for_portion) or provide exclusions. The context is clear but not elaborated.

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