Start the open UCP purchase flow — no auth needed. Creates a cart session and returns a cart_id (24-hour TTL). Optionally seed with pre-configured blind items and customer details. Next step: update_cart to add items, then create_checkout → complete_checkout to mint the payment link.
| Name | Required | Description | Default |
|---|---|---|---|
| items | No | Optional initial items (configured blinds) | |
| customer | No | Optional customer details |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden. It discloses key behaviors: no auth needed, returns a cart_id with a 24-hour TTL, and optional seeding with items/customer. This adds significant context beyond a basic 'creates a cart'. It doesn't mention error cases or idempotency, but for this simple creation tool, it's fairly transparent.
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?
The description is three sentences, front-loaded with the primary action, followed by key details and next steps. Every sentence contributes value with no filler, making it exceptionally concise and well-structured.
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 simple tool with two optional parameters and no output schema, the description is complete. It explains the purpose, return value (cart_id), TTL, and next steps in the flow. No critical information is missing for an agent to select and invoke this tool correctly.
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% (items and customer both have descriptions). The description adds the concept of 'seed' and clarifies items are 'pre-configured blind items', but this largely restates what's in the schema. It provides minor additional semantics without deep detail, hence a baseline 3.
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?
The description clearly states the tool's purpose: 'Start the open UCP purchase flow' and 'Creates a cart session and returns a cart_id'. It uses a specific verb and resource, distinguishing it from siblings like cancel_cart, update_cart, and get_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?
It explicitly provides a workflow: 'Next step: update_cart to add items, then create_checkout → complete_checkout'. This indicates exactly when to use this tool (at the start) and how it fits with related tools. It also notes 'no auth needed', setting clear expectations.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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Most tools have distinct purposes, but the presence of three search tools (search_catalog, search_products, lookup_catalog) and legacy tools (create_order, submit_enquiry) creates minor overlap. Descriptions help differentiate, but an agent might initially confuse them.
All 26 tool names follow a consistent verb_noun snake_case pattern (e.g., cancel_cart, configure_product). No mixed cases or irregular verbs are present.
26 tools is slightly high for a blind shop, but the domain requires many operations (search, pricing, cart, checkout, recommendations, etc.). Some legacy tools could be removed, but the count is still reasonable.
The tool surface covers the full customer journey from product discovery (search, recommendations) to purchase (cart, checkout, payment) and post-purchase (orders, swatches, price match, delivery estimates). No obvious gaps for the stated purpose.