get_cartView a Picnic shopping cart with product quantities, prices, total, and delivery window; see unavailable items and offered replacements before ordering.
Show the user's Picnic shopping cart: the products with their quantity and price, the total, and the delivery window. A product that can't be delivered in that window has unavailable with the reason, and replacements Picnic offers instead.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v1.0.0Does 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 genuine behavioral context the annotations lack: the result includes per-product availability with a reason and drugstore-style replacement suggestions, which tells the agent to expect partial-unavailability handling rather than a plain list.
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 sentences, front-loaded with the core purpose, followed by the edge-case return details. Every clause (quantity, price, total, delivery window, unavailable reason, replacements) carries information about the payload.
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 no parameters and no output schema, the description bears the burden of explaining the return shape, and it does so thoroughly: line items, totals, delivery window, and the unavailable/replacements cases. Nothing an agent needs to interpret the response 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?
The tool takes zero parameters, so the schema has nothing to explain and the baseline is 4. The description correctly implies the cart is scoped to the authenticated user with no arguments needed.
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 ('Show the user's Picnic shopping cart') and enumerates exactly what is returned: products, quantity, price, total, delivery window, plus unavailable/replacements. This makes it clearly distinguishable from the mutating cart siblings (add_to_cart, remove_from_cart, set_cart_quantity) without opening any 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?
The read-only framing implies when to use it (to inspect cart state before mutating or checking out), but there is no explicit guidance such as 'call this after add_to_cart' or when to prefer a sibling. Usage is inferred from the verb and the sibling list rather than stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.