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

Annotations already declare readOnlyHint, destructiveHint, idempotentHint, and openWorldHint. The description adds significant behavioral context: it returns 'all serving sizes' and a comprehensive list of nutrients (calories, fats, etc.), plus the data scale '2.3M+ foods'. This provides value beyond annotations and does not contradict them.

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 concise sentence that fronts the core purpose, then lists key nutrients and data scale. No wasted words; every phrase 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?

Given the single required parameter, full schema coverage, presence of output schema, and comprehensive annotations, the description completes the context by detailing what data is returned. It implicitly connects to the sibling search tool, making the overall usage pattern clear.

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% with a clear description of 'food_id'. The tool description reiterates 'by FatSecret ID' but adds no new detail beyond the schema. Per the baseline rule for high coverage, a score of 3 is appropriate.

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 function: 'Complete nutritional profile for a food item by FatSecret ID'. It specifies the resource (food item) and action (retrieve profile). The mention of ID differentiates it from the sibling 'nutrition.fatsecret.search' tool, implying that this tool is for details after a search.

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 that the tool requires a FatSecret ID obtained from search results, providing clear context on when to use it (after search). However, it does not explicitly state when not to use it or name the search tool as an alternative, so it stops short of full explicit guidance.

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