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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely non-obvious behavior beyond that: no purchase or charge occurs, and "Los precios los calcula la tienda" warns the agent not to quote or compute prices itself. It still says nothing about what the returned link looks like or how invalid productoId values are handled.

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?

Three short sentences with zero waste, front-loaded with the most important constraint ("NO compra ni cobra") before the mechanics and the pricing caveat. Every sentence 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 read-only, closed-world tool with strong annotations and no output schema, the description covers the essential framing: it produces a link, it does not transact, and pricing lives in the store. What's missing is the shape of the result (a URL string) and failure behavior for unknown products, which the agent would otherwise have to discover by calling.

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 coverage is only 50%: slug is documented in-schema but the items array and its fields (productoId, talle, cantidad, color) carry no descriptions, and constraints like maxItems 20 and cantidad 1-20 exist only as machine constraints. The description decodes no parameters at all — not even that items are the 'prendas precargadas' — so it fails to compensate for the coverage gap.

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 ("Arma un link al carrito de la tienda con las prendas precargadas") and explicitly negates the adjacent action ("NO compra ni cobra"), which prevents a serious misread. It does not, however, distinguish itself from the close sibling armar_carrito_por_texto, so the agent must infer which of the two cart-building tools applies.

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 describes the downstream flow (person opens the link, fills data, pays in the store), which implies the tool is for handing off a sale to the store rather than completing it. But there is no explicit "use this when / not when" and no pointer to armar_carrito_por_texto or armar_kit as alternatives, leaving the selection rule implied only.

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