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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), yet the description still adds genuinely non-obvious behavior: unpublished nutrients surface in an `incomplete` field and the total is an underestimate. That return-value caveat is exactly what annotations cannot convey and there is no output schema to carry it. It omits any mention of the 30-item cap or quantity bounds.

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?

Two tight sentences with zero filler; the core action is front-loaded and the caveat follows as supporting detail. Every clause 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?

For a single-parameter aggregation tool with no output schema, the description covers the action, the input source, and the one surprising output behavior (`incomplete`). It would be fully complete if it mentioned the item/quantity limits an agent must respect.

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 reinforces the source of the `id` value (search_menu) and frames `items` as "a set of items," but says nothing about the nesting, the per-item `quantity` field, its default of 1, or the 0.1–20 range and 30-item cap. It adds only marginal meaning over the schema.

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 ("Add up nutrition for a set of items") and scopes it with concrete use cases ("a meal, a day"). It also names the sibling tool that produces the required input ("ids from search_menu"), so it is distinguishable from list_chains and request_missing without opening a 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?

Gives clear usage context (aggregating a meal or a day) and an implicit prerequisite: items must come from search_menu. It does not state when NOT to use it or name an alternative path, so it stops short of full when/when-not guidance.

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