update_custom_food

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

The description goes well beyond annotations by explaining partial updates ('Only what you pass changes'), diary linkage, nutrient merging, and the dual behavior of measures (fix vs. add). These details align with the idempotentHint and destructiveHint annotations rather than contradicting 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 detailed but each part earns its place, especially given the 0% schema coverage. Behavioral guarantees are front-loaded, and the Args section is dense but structured without wasted words.

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 5-parameter mutation tool with no schema descriptions, the description covers the essential semantics: scoping, merge behavior, measure handling, and related lookup guidance. Since an output schema exists, omitting return-value details is acceptable.

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 input schema has no descriptions at all, but the description fully documents all five parameters, including the ambiguous 'measures' array with optional fields and the add-vs-edit distinction. It also directs the agent to list_nutrients for accepted nutrient names.

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 opens with a specific verb and resource: 'Edit one of your custom foods in place, keeping its diary entries.' It clearly differentiates from sibling tools like add_custom_food, list_custom_foods, and retire_custom_food by emphasizing in-place editing and diary preservation.

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 concrete use cases: fixing typos or wrong nutrients without re-logging, and correcting or adding measures. It does not explicitly state when not to use it or name alternatives like retire_custom_food, but the context is clear enough for an agent to select it appropriately.

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