Whether a hub error means "this prompt/tag does not exist" (a 404) rather than
a transient failure (network/5xx/auth/rate-limit). Callers use this to decide
whether falling back — or treating a prompt as new — is safe; a transient
failure must not be silently misread as "absent".
langchain-hub / langsmith throw plain, untyped errors (there is no typed
not-found to instanceof), so we sniff the status code and fall back to the
message text; the shapes this is expected to classify are pinned in
hub.test.ts.
Whether a hub error means "this prompt/tag does not exist" (a 404) rather than a transient failure (network/5xx/auth/rate-limit). Callers use this to decide whether falling back — or treating a prompt as new — is safe; a transient failure must not be silently misread as "absent".
langchain-hub / langsmith throw plain, untyped errors (there is no typed not-found to
instanceof), so we sniff the status code and fall back to the message text; the shapes this is expected to classify are pinned inhub.test.ts.