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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds genuinely useful negative disclosure ('No prices') that stops the agent expecting pricing data, and enumerates the returned payload, though return shape is largely covered by the output schema.

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?

A single front-loaded sentence carrying the resource, market scope and payload, followed by a two-word exclusion. Nothing is wasted.

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?

With annotations carrying safety, a 100%-covered two-parameter schema, and an output schema covering returns, the definition is essentially complete. Only the routing logic (item_id comes from mcdonalds_menu) is left to the schema rather than the description.

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 100% and both parameters (country default 'us', item_id source) are fully documented there. The description's market list and matching rule duplicate the schema rather than extending it, so the baseline 3 applies.

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?

Names the exact resource (McDonald's item nutrition), the market scope (seven named markets), and the returned content (nutrients, allergens, ingredients, image). The explicit 'No prices' line cleanly separates it from mcdonalds_menu and mcdonalds_item_list, so an agent can pick it without opening sibling schemas.

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?

Usage is only implied: it tells the agent the market must be one of seven and that country must match the item's origin, plus the 'No prices' caveat. It never states when to choose this over mcdonalds_item_list or mcdonalds_menu, or that item_id must be sourced from the menu first.

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