workspace_handoff_not_found
No delivery handoff (or prerequisite/milestone of it) of that id that you can open. A rep opens handoffs they send, receive, fall back for, or whose deal they own.
Problem shape
Every non-2xx response is an RFC 9457 application/problem+json body. The type URI below is stable and machine-matchable, so branch on the final path segment (the code) and treat the status as redundant confirmation. See the error-handling guide.
{
"type": "https://docs.vocapable.com/errors/workspace_handoff_not_found",
"title": "…",
"status": 404,
"detail": "…",
"instance": "/v1/…"
}