docs: remove deprecated id field from checkout update request examples

[raginpirate]

Description

We cemented our transition from required -> omit on this id the other month, but forgot to cleanup the deprecated doc markers. Now removed! #341

Category (Required)

Please select one or more categories that apply to this change.

• Core Protocol: Changes to the base communication layer, global context, or breaking refactors. (Requires Technical Council approval)
• Governance/Contributing: Updates to GOVERNANCE.md, CONTRIBUTING.md, or CODEOWNERS. (Requires Governance Council approval)
• Capability: New schemas (Discovery, Cart, etc.) or extensions. (Requires Maintainer approval)
• Documentation: Updates to README, or documentations regarding schema or capabilities. (Requires Maintainer approval)
• Infrastructure: CI/CD, Linters, or build scripts. (Requires DevOps Maintainer approval)
• Maintenance: Version bumps, lockfile updates, or minor bug fixes. (Requires DevOps Maintainer approval)
• SDK: Language-specific SDK updates and releases. (Requires DevOps Maintainer approval)
• Samples / Conformance: Maintaining samples and the conformance suite. (Requires Maintainer approval)
• UCP Schema: Changes to the ucp-schema tool (resolver, linter, validator). (Requires Maintainer approval)
• Community Health (.github): Updates to templates, workflows, or org-level configs. (Requires DevOps Maintainer approval)

Checklist

• I have followed the Contributing Guide (including Conventional Commits title requirements and ! for breaking changes).
• I have updated the documentation (if applicable).
• My changes pass all local linting and formatting checks.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• (For Core/Capability) I have included/updated the relevant JSON schemas.
• I have regenerated Python Pydantic models by running generate_models.sh under python_sdk.

[damaz91]

Thanks for the cleanup @raginpirate ! Can you make sure to also clean the MCP examples (like https://ucp.dev/draft/specification/checkout-mcp/#request_1) and Embedded (like https://ucp.dev/draft/specification/embedded-checkout/#ectotalschange - not sure about Embedded tbh)

[raginpirate]

Good ask to trust but verify @damaz91! I went and swept the repo.

MCP — the id you spotted isn't inside the checkout object. It sits next to it, as a tool argument:

"arguments": {
  "id": "checkout_abc123",     // target resource
  "checkout": { ... }          // no id in here
}

mcp.openrpc.json defines update_checkout params as [meta, id, checkout], so id is doing exactly the job the URL path does in REST. It has to stay.

Embedded — the ec.* messages aren't requests, they're the business pushing checkout state out to the host. The omit annotation only covers what the platform sends in, so checkout.id is a normal field there and belongs in the payload.

So I think this is the only patch we need to make!

[damaz91]

Thanks for double checking @raginpirate ! LGTM.

While reviewing the holistic deprecation of "id" in update_checkout, I noticed the OpenAPI schema is not marking it as "omit" as it should. Opened #649 to track.

[jingyli]

Thanks for the quick fix! Hopefully this won't happen again now that we have an enhanced presubmit hook (and this should be caught alongside #341).