Prepare the final buyer handoff by returning the merchant-hosted HTTPS checkout URL. Use when the user has a cart and clearly wants to proceed to checkout or purchase. Always surface checkoutUrl to the human buyer. Agent Checkout never collects raw card details and this tool does not itself charge the buyer.
| Name | Required | Description | Default |
|---|---|---|---|
| cart_id | Yes | ||
| site_slug | Yes |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral burden and discloses safety-relevant behavior: it does not collect raw card details, does not itself charge the buyer, and always returns a merchant-hosted HTTPS URL. This goes beyond what the schema conveys.
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?
Four short sentences, each contributing a distinct requirement: output form, trigger condition, buyer-facing handling, and payment-safety caveat. 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 two-parameter tool with no output schema, the description covers what it returns, when to use it, and what it does not do. It falls just short of fully complete because it does not state how site_slug is determined or what happens on failure.
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 0% because the description never mentions cart_id or site_slug. With low coverage, the description should compensate, but it only indirectly implies cart_id through 'has a cart' and leaves site_slug entirely unexplained.
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 clear verb ('Prepare') and resource ('merchant-hosted HTTPS checkout URL'), and specifies when to use it. The sentence about user wanting to proceed to checkout distinguishes this from cart-management siblings like get_cart and create_cart.
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?
Explicitly says to use when the user has a cart and clearly wants to proceed to checkout or purchase. It does not list alternatives or state when not to use, but it gives enough context to route correctly.
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 steps in the purchase flow, and descriptions clarify the intended sequence. The main overlap is search_catalog being a legacy alias for search_products; check_inventory and get_product have slight overlap but are distinguished by availability checking versus detailed product info.
All tool names follow a consistent verb_noun snake_case pattern such as search_products, get_product, create_cart, add_to_cart, and create_checkout. The naming pattern makes the workflow stage and action immediately clear.
With 8 tools, the surface is well-scoped for a shopping-and-checkout flow: discovery, product details, inventory, cart creation/modification, cart review, and checkout handoff. The redundant search_catalog alias is minor and does not make the set feel bloated.
The core path is complete: search → product details → inventory check → create cart → add to cart → get cart → create checkout. Minor gaps such as removing or updating cart items are missing, but the essential purchase workflow is fully supported.