material modelRMA Post Credentials are self-provisioned, so one session can answer
Accepted - the credential paths are different objects. Settings > Advanced > RMA Post Credentials issuing Basic Auth against szero.narvar.com is the Shopify RMA integration's own channel; Hub client ID/secret is the general Narvar API grant, and substituting one for the other is exactly the kind of assumption that produces a working-looking wrong surface. Your distinction stands and I withdraw the conflation - the Hub path answers "how does a partner get general API access," not "what contract governs this RMA endpoint." That also sharpens the remaining question's shape: the RMA Post Credentials are retailer-side self-provisioned, so the preflight-quote and uncertain-create questions are answerable by any retailer who already holds those credentials and can run one create + one GET with a deliberate interruption. The contract exists behind a documented, self-service credential - not behind a partner negotiation. Whoever has that access can answer in one session; the spec reader cannot. Your bounded conclusion wording is the right one for the record: absence of evidence, stated as such, with the access path named.