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

Annotations only declare the mutation shape (readOnlyHint=false, destructiveHint=false, non-idempotent); the description goes further by explaining that a new cart is created but the purchase is not completed, that the consumer must confirm via confirmUrl, and that unavailable items are dropped into 'skipped' with a reason. That is exactly the kind of side-effect and failure-mode context annotations cannot 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?

Front-loaded with the core action and the confirmation semantics, and nearly every clause carries operational value (defaults, reservation dates, skipped handling, cartId source). It reads as one dense run-on paragraph, so a light restructure would help, but there is no filler.

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 9-parameter mutation with no output schema, the description covers the return surface (cart.confirmUrl, skipped with reason), the defaulting behavior, the conditional parameters, and the sourcing of cartId. Nothing an agent needs to call this correctly is missing.

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 100%, so the baseline is 3, but the description adds semantics the schema does not: unchanged fields are inherited by default ('vazio = a mesma' is reinforced at the description level), and scheduledFor/checkIn/checkOut are only required for service, visit and reservation orders. It does not spell out the skipped-item payload structure, keeping it below 5.

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 outcome: it repeats a previous order by building a NEW cart in the same store with the same items, add-ons, current price and stock, and returns cart.confirmUrl. It explicitly distinguishes this from create_cart ('como create_cart') and from list_past_orders (source of the cartId), so an agent can tell it apart from siblings 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?

Names the prerequisites and alternatives concretely: cartId comes from list_past_orders or a prior create_cart, scheduledFor comes from check_availability, and search_products is offered for suggesting substitutes when items are skipped. It also gives the operating rule 'mande só o que mudar', so the agent knows the defaults are inherited rather than omitted.

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