create_custom_food

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

With no annotations, the description discloses the mutation ('Creates a new food item'), success response IDs, and the 204 no-data edge case. It also warns that nutrients are absolute values per serving, not %DV, which is behavioral context beyond the schema. It doesn't cover permissions or all failure modes, but this is strong for an unannotated tool.

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?

Front-loads purpose, then response/error handling, unit warning, and a structured Args list. Some redundancy exists between 'Create a custom food' and 'Creates a new food item', but the length is justified by 18 parameters with zero schema descriptions.

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 an 18-parameter creation tool with no annotations, the description covers every parameter's unit/meaning, explains the 204 fallback, and connects to log_custom_food. An output schema exists, so the description doesn't need to detail the full return shape; nothing essential for correct invocation is missing.

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 0%, but the Args section documents all 18 parameters with units, defaults, and examples (e.g., serving_unit 'G','ML','OZ', default 100). It explicitly flags calcium, iron, and vitamin D as absolute mg/mcg values rather than %DV, adding meaning the schema does not provide.

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?

States a specific verb+resource: 'Create a custom food in the user's Garmin nutrition library' and clarifies it creates a new food item with per-serving nutrition. This separates it from logging, updating, deleting, and food search siblings.

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?

Provides clear context: response yields foodId and servingId needed for log_custom_food, and the 204 no-data fallback routes to get_custom_foods(search=food_name). It does not explicitly exclude update_custom_food for existing items, so it stops short of a full when-to-use/alternative matrix.

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