Reliability and Resilience Assessment

Evaluate the reliability and resilience of this cloud system:
[Describe architecture and critical services]

Identify single points of failure, availability risks, and practical ways to improve resilience.

Act as an API designer who cares most about consistency and about the developers who will call this API. Design a REST API from the brief below.

BRIEF
Product and domain: [Product and domain]
Who will call the API: [API consumers]
What it must let them do: [What callers must be able to do]
Authentication: [Authentication]
Existing conventions or constraints: [Existing conventions or constraints]
Deliverable format: [Deliverable format]

WORK IN THIS ORDER

1. Resource model. List each resource, its key fields with types, and its relationships. Separate the fields a client may write from those the server sets. Note any resource you considered and rejected.

2. Conventions, decided once. State the rule for each of these and apply it everywhere afterward: URL and field naming, identifier format, timestamps, pagination style, filtering and sorting parameters, the single error body shape (for example RFC 9457 problem details), partial updates, versioning, and how repeated POST requests are made safe.

3. Endpoints. A table with method, path, purpose, success status, and the error statuses a client must handle. Paths are nouns. If an operation does not fit create, read, update or delete, model it as a sub-resource or a clearly named action and explain the choice in one line.

4. Worked examples. For the three operations a new integrator would call first, show a full request and response, plus one realistic error response each.

5. Authorization. Per endpoint or group: who may call it, and what a caller who lacks access receives.

6. Decisions for a human. Trade-offs you resolved by assumption, each with the alternative and what would change your mind.

CONSTRAINTS
- Do not invent business rules, limits or fields beyond the brief. Where you need one to proceed, label it ASSUMED.
- Status codes must mean what HTTP says they mean. No 200 responses carrying an error body.
- Every list endpoint is paginated and has a stated default and maximum page size, marked ASSUMED if I gave none.
- Never expose internal details such as database column names or sequential ids if the brief suggests they are sensitive.
- If two requirements in the brief conflict, say so instead of quietly choosing.

OUTPUT
Six numbered sections as above, in the deliverable format. No introduction and no closing summary.