add_to_cartBuild a ready-to-checkout cart and return a cart link. The shopper completes checkout and payment securely on the store. Pass one or more line items.
| Name | Required | Description | Default |
|---|---|---|---|
| items | Yes | Line items to add to the cart |
| Name | Required | Description | Default |
|---|---|---|---|
| items | Yes | ||
| cart_url | Yes | ||
| checkout | No |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond annotations (readOnly=false, idempotent=true, destructive=false), the description discloses that the tool returns a cart link and that checkout/payment happen securely on the storefront, so the agent knows it is not processing payment. It does not describe cart persistence or repeated-call behavior, but annotations already cover safety and idempotency.
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, each earning its place: outcome, payment handoff, and input requirement. No redundant restating of the title or schema.
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?
The definition is sufficient for a one-parameter cart-building tool: it explains the outcome, input shape, and checkout flow, and an output schema exists. Minor details like behavior on repeated calls or invalid stock are not specified, but they are not essential for correct invocation.
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 covers 100% of the parameter documentation, including product, variant, and quantity fields. The description adds only the 'one or more line items' constraint, which is useful but minor, so the baseline 3 is appropriate.
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?
Description uses a specific verb ('Build') and resource ('ready-to-checkout cart'), and states the outcome (cart link, shopper completes checkout/payment). This clearly differentiates it from read-oriented siblings like list_products, search, and check_inventory.
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?
Clear context is provided: use it when constructing a ready-to-checkout cart with one or more line items. It does not explicitly name sibling alternatives or state when not to use it, but the context is enough to select it for cart creation.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Most tools target distinct actions: browse, search, product detail, inventory, recommendations, cart, and store policy. The main potential confusion is between get_product and check_inventory, which both report product/variant price and stock, though list_products vs search_products is reasonably clear from descriptions.
Tool names are consistently snake_case and many follow a verb_noun pattern like check_inventory, get_product, list_products, and search_products. However, best_sellers, related_products, and store_info are noun phrases, while fetch and search are bare verbs, making the naming pattern mixed but still readable.
Eleven tools is well-scoped for an e-commerce shopping assistant covering catalog browsing, product search, inventory checks, recommendations, cart assembly, content search, and store policies. Each tool has a clear purpose and the count is neither bloated nor too thin.
The tool set covers the full shopper-facing journey: discovering categories and products, searching content, viewing product details and stock, seeing best sellers and related items, checking store policies, and building a cart. As a read-only storefront gateway, missing merchant-side operations are outside its stated purpose.