fitbit_preview_meal

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

Annotations cover mutation/safety (readOnlyHint=false, destructiveHint=false, idempotentHint=true), so the bar is lower. The description still adds real value by clarifying the write is local/non-persisted and warning that photo-based estimates are approximate, which the annotations do not convey.

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?

Four short sentences, front-loaded with the scope constraint, and each carries distinct information. No filler or repetition.

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 4 required params at 0% schema coverage, no output schema, and a draft/commit workflow, the description covers the critical unit-of-measure caveat and the review-before-save obligation. It stops short of explaining the requestId idempotency key or the mealType enum, so it is not fully complete.

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%, so the description must carry parameter meaning. It adds a genuinely important semantic ('values apply to the whole dish portion, not per 100g'), references date/offset and assumptions, and names the K/P/F/C fields, but leaves requestId and mealType unexplained. Partial compensation only.

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 and resource ('Create a local meal draft') and the capitalized 'ONLY' explicitly scopes the operation as non-persistent, distinguishing it from the commit step in the sibling set (fitbit_commit, fitbit_cancel_draft). An agent can tell what this does without opening the schema.

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?

Implies a downstream save step via 'Review ... before saving' and signals this is a draft rather than a finalized entry, but it never names the alternative (e.g., fitbit_commit) or states when to choose preview vs commit. Usage is inferable from the 'ONLY' phrasing rather than spelled out.

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