diff --git a/ingestion/internal/extract/docmark.go b/ingestion/internal/extract/docmark.go
index 4281742..b3190ac 100644
--- a/ingestion/internal/extract/docmark.go
+++ b/ingestion/internal/extract/docmark.go
@@ -97,8 +97,13 @@ func extractViaDocmark(path string) (string, error) {
 		return "", fmt.Errorf("docmark: HTTP %d: %s", resp.StatusCode, string(body))
 	}
 
+	jsonBody := body
+	if data := sseDataPayload(body); data != nil {
+		jsonBody = data
+	}
+
 	var out docmarkResponse
-	if err := json.Unmarshal(body, &out); err != nil {
+	if err := json.Unmarshal(jsonBody, &out); err != nil {
 		return "", fmt.Errorf("decode docmark response: %w", err)
 	}
 	if out.Error != nil {
@@ -114,6 +119,23 @@ func extractViaDocmark(path string) (string, error) {
 	return text, nil
 }
 
+// sseDataPayload extracts the JSON payload from an SSE-framed response body
+// ("event: message\r\ndata: {...}\r\n\r\n"). docmark's Streamable-HTTP
+// transport frames every response this way (Content-Type: text/event-stream)
+// regardless of stateless_http — that flag removes the session/initialize
+// requirement, not the SSE wire framing. Returns nil if body isn't SSE-framed
+// (e.g. a plain-JSON response, kept as a fallback for forward-compatibility).
+func sseDataPayload(body []byte) []byte {
+	const prefix = "data: "
+	for _, line := range bytes.Split(body, []byte("\n")) {
+		line = bytes.TrimRight(line, "\r")
+		if bytes.HasPrefix(line, []byte(prefix)) {
+			return bytes.TrimPrefix(line, []byte(prefix))
+		}
+	}
+	return nil
+}
+
 // fileBase returns the final path segment (like filepath.Base, kept local to
 // avoid importing path/filepath just for this one call).
 func fileBase(path string) string {
diff --git a/ingestion/internal/extract/docmark_test.go b/ingestion/internal/extract/docmark_test.go
index 7ae6ae5..06da518 100644
--- a/ingestion/internal/extract/docmark_test.go
+++ b/ingestion/internal/extract/docmark_test.go
@@ -30,9 +30,17 @@ type mcpToolResult struct {
 	} `json:"error,omitempty"`
 }
 
+// writeMCPResponse mirrors docmark's REAL response framing (empirically
+// confirmed against the live server): Content-Type: text/event-stream,
+// body is SSE-framed ("event: message\r\ndata: {...}\r\n\r\n"), not bare
+// JSON -- inherent to MCP Streamable-HTTP, independent of stateless_http.
 func writeMCPResponse(w http.ResponseWriter, body mcpToolResult) {
-	w.Header().Set("Content-Type", "application/json")
-	_ = json.NewEncoder(w).Encode(body)
+	payload, _ := json.Marshal(body)
+	w.Header().Set("Content-Type", "text/event-stream")
+	w.WriteHeader(http.StatusOK)
+	_, _ = w.Write([]byte("event: message\r\ndata: "))
+	_, _ = w.Write(payload)
+	_, _ = w.Write([]byte("\r\n\r\n"))
 }
 
 func TestExtractViaDocmark_Success(t *testing.T) {