mfp_add_food_to_diary

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

The description correctly states that the tool mutates the diary by adding an entry and returns a confirmation string. This aligns with annotations (readOnlyHint=false, idempotentHint=false). It adds a small amount of context by noting the date and quantity defaults, but it does not disclose whether entries are appended vs. replaced, how duplicates are handled, or whether authentication/session state is required. Annotations cover the basic safety profile, so this does not feel like a serious gap.

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 front-loaded with the core purpose, followed by a brief usage pointer and a structured Args list. It is reasonably sized and easy to scan. The Args block is slightly redundant with the schema, and the first two sentences could be tightened, but overall it is organized and free of fluff.

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 tool with five documented parameters, an output schema, and annotations indicating a mutating operation, the description supplies the essential execution chain: search for the food, obtain mfp_id, then add with date/meal/quantity/unit. It does not leave major calling details uncovered. It could mention alternative addition routes or duplicate behavior, but those are secondary for basic invocation.

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 description's Args block echoes the parameter information already present in the input schema, which documents all five fields with defaults and examples. It does add the closed set of allowed meal names ('Breakfast', 'Lunch', 'Dinner', 'Snacks') and explicitly ties mfp_id to mfp_search_food. However, most of the value is redundant with the schema, so it only modestly exceeds the baseline.

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 clear, specific statement: 'Add a food item to your MyFitnessPal food diary for a specific date and meal.' It identifies the verb (add), the resource (food entry in diary), and the key qualifiers (date, meal). However, it does not distinguish itself from similarly purposed siblings like mfp_log_meal or mfp_bulk_log, so it falls short of a 5.

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 only usage hint is that users should call mfp_search_food first to obtain mfp_id. There is no explicit guidance on when to use this tool versus alternatives such as mfp_log_meal, mfp_bulk_log, or mfp_edit_food, and no exclusion criteria are given. The context is implied rather than stated.

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