Found via a real live-cluster end-to-end test (POST /ingest-path with a real
.docx against the deployed ingestion + docmark): 'decode docmark response:
invalid character e looking for beginning of value'. docmark's Streamable-HTTP
transport frames every response as SSE (event: message\r\ndata: {...}\r\n\r\n,
Content-Type: text/event-stream) -- stateless_http=True removes the need for
an initialize handshake/session ID, it does NOT change the wire framing to
bare JSON. My original client + its own test mock both assumed bare JSON,
so the unit tests passed while the real call failed.
sseDataPayload() extracts the data: line before JSON-unmarshaling; falls back
to the raw body if no SSE framing is present (forward-compatible). Test mock
(docmark_test.go) now emits the SAME framing the live server actually sends,
confirmed by directly probing docmark's live response before writing the fix.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>