Cancel a checkout session before completion, releasing its inventory hold. Idempotent, owner-scoped, and moves no money (distinct from an escrow refund). REQUIRES IDENTITY plus an Idempotency-Key on a signature-required Terminal.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | The checkout session id. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description fully bears the transparency burden. It discloses idempotency, owner scoping, that no money moves, and the requirement for identity, Idempotency-Key, and a signature-required terminal. It also explains the inventory release effect.
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 exceptionally concise, with three sentences each serving a distinct purpose: action/effect, behavioral traits, and prerequisites. There is no redundancy or filler, and the most important information is front-loaded.
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 tool with only one parameter and no output schema, the description is remarkably complete. It covers the purpose, effects, constraints, and prerequisites, enabling an agent to invoke it correctly without ambiguity.
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 single parameter 'id' is fully described in the schema as 'The checkout session id.' The description does not add any parameter-specific semantics, so it meets the baseline for high schema coverage without needing further elaboration.
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 action ('Cancel a checkout session'), its temporal scope ('before completion'), and the specific effect ('releasing its inventory hold'). This distinguishes it from sibling tools like cancel_cart and complete_checkout.
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 description specifies when to use the tool ('before completion'), scopes it to the owner, and explicitly distinguishes it from an escrow refund. However, it does not name alternative tools for related actions (e.g., cancel_cart), so it stops short of fully explicit alternatives.
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 map to a distinct lifecycle step, and the detailed descriptions separate discovery, cart, checkout, payment, order, and wishlist concerns well. However, get_product and lookup_catalog are largely the same lookup by identifier, discover_products and search_catalog overlap across scope, and update_checkout is actually a read-only no-op.
The set overwhelmingly follows a verb_noun pattern: create_cart, get_checkout, cancel_checkout, complete_checkout, search_catalog. Minor deviations are the wishlist_* resource-first subgroup and the misleading update_checkout, which does not perform an update.
At 23 tools, this sits at the heavy end of the range, though the broad commerce lifecycle does justify substantial surface area. The count is inflated by redundant product lookup tools and a no-op update_checkout, so a more trimmed set in the low-to-mid teens would be healthier.
The server covers the full shopper lifecycle well: discovery, product lookup, cart, checkout, payment, order placement, order read, refunds, and wishlist. Gaps are minor and workable, such as update_checkout not actually supporting updates and no explicit order-cancellation path once a checkout is complete.
