Skip to content

docs: clarify the idempotency-key server contract in the checkout MCP binding #679

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
YanisMtcr wants to merge 1 commit into
base: main
Choose a base branch
from
Open

docs: clarify the idempotency-key server contract in the checkout MCP binding #679

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 13 additions & 0 deletions docs/specification/shopping/checkout/mcp.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -109,6 +109,19 @@ The `meta["ucp-agent"]` field is **required** on all requests to enable
`meta["idempotency-key"]` for retry safety. Platforms **MAY** include
additional metadata fields.

### Idempotency

`complete_checkout` and `cancel_checkout` are state-changing operations and
**MUST** carry `meta["idempotency-key"]` (see [Request Metadata](#request-metadata)).
Servers **MUST** apply the same idempotency contract as the REST binding
([Specific Header Requirements](rest.md#specific-header-requirements)):
store the key with the operation result, return the cached result for a duplicate
key whose request matches the original, and treat a key reused with a mismatched
request as a conflict. Over MCP that conflict surfaces as the JSON-RPC error the
[error registry](../../overview/index.md#error-handling) maps from HTTP `409` (`-32000`). See
[Message Signatures — Replay Protection](../../signatures.md#replay-protection) for the
full payload-matching contract.

## Tools

UCP Capabilities map 1:1 to MCP Tools.
Expand Down
Loading