diff --git a/codeagent-wrapper/main_test.go b/codeagent-wrapper/main_test.go
index 0193066..e5fc37b 100644
--- a/codeagent-wrapper/main_test.go
+++ b/codeagent-wrapper/main_test.go
@@ -1582,6 +1582,34 @@ func TestBackendParseJSONStream_ClaudeEvents(t *testing.T) {
 	}
 }
 
+func TestBackendParseJSONStream_ClaudeEvents_ItemDoesNotForceCodex(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+	}{
+		{
+			name:  "null item",
+			input: `{"type":"result","result":"OK","session_id":"abc123","item":null}`,
+		},
+		{
+			name:  "empty object item",
+			input: `{"type":"result","subtype":"x","result":"OK","session_id":"abc123","item":{}}`,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			message, threadID := parseJSONStream(strings.NewReader(tt.input))
+			if message != "OK" {
+				t.Fatalf("message=%q, want %q", message, "OK")
+			}
+			if threadID != "abc123" {
+				t.Fatalf("threadID=%q, want %q", threadID, "abc123")
+			}
+		})
+	}
+}
+
 func TestBackendParseJSONStream_GeminiEvents(t *testing.T) {
 	input := `{"type":"init","session_id":"xyz789"}
 {"type":"message","role":"assistant","content":"Hi","delta":true,"session_id":"xyz789"}
@@ -1598,6 +1626,43 @@ func TestBackendParseJSONStream_GeminiEvents(t *testing.T) {
 	}
 }
 
+func TestBackendParseJSONStream_GeminiEvents_DeltaFalseStillDetected(t *testing.T) {
+	input := `{"type":"init","session_id":"xyz789"}
+{"type":"message","content":"Hi","delta":false,"session_id":"xyz789"}
+{"type":"result","status":"success","session_id":"xyz789"}`
+
+	message, threadID := parseJSONStream(strings.NewReader(input))
+
+	if message != "Hi" {
+		t.Fatalf("message=%q, want %q", message, "Hi")
+	}
+	if threadID != "xyz789" {
+		t.Fatalf("threadID=%q, want %q", threadID, "xyz789")
+	}
+}
+
+func TestBackendParseJSONStream_GeminiEvents_OnMessageTriggeredOnStatus(t *testing.T) {
+	input := `{"type":"init","session_id":"xyz789"}
+{"type":"message","role":"assistant","content":"Hi","delta":true,"session_id":"xyz789"}
+{"type":"message","content":" there","delta":true}
+{"type":"result","status":"success","session_id":"xyz789"}`
+
+	var called int
+	message, threadID := parseJSONStreamInternal(strings.NewReader(input), nil, nil, func() {
+		called++
+	})
+
+	if message != "Hi there" {
+		t.Fatalf("message=%q, want %q", message, "Hi there")
+	}
+	if threadID != "xyz789" {
+		t.Fatalf("threadID=%q, want %q", threadID, "xyz789")
+	}
+	if called != 1 {
+		t.Fatalf("onMessage called=%d, want %d", called, 1)
+	}
+}
+
 func TestBackendParseJSONStreamWithWarn_InvalidLine(t *testing.T) {
 	var warnings []string
 	warnFn := func(msg string) { warnings = append(warnings, msg) }
diff --git a/codeagent-wrapper/parser.go b/codeagent-wrapper/parser.go
index 5f186ca..ecf27e6 100644
--- a/codeagent-wrapper/parser.go
+++ b/codeagent-wrapper/parser.go
@@ -85,7 +85,7 @@ type UnifiedEvent struct {
 	// Gemini-specific fields
 	Role    string `json:"role,omitempty"`
 	Content string `json:"content,omitempty"`
-	Delta   bool   `json:"delta,omitempty"`
+	Delta   *bool  `json:"delta,omitempty"`
 	Status  string `json:"status,omitempty"`
 }
 
@@ -148,9 +148,17 @@ func parseJSONStreamInternal(r io.Reader, warnFn func(string), infoFn func(strin
 		}
 
 		// Detect backend type by field presence
-		isCodex := event.ThreadID != "" || len(event.Item) > 0
+		isCodex := event.ThreadID != ""
+		if !isCodex && len(event.Item) > 0 {
+			var itemHeader struct {
+				Type string `json:"type"`
+			}
+			if json.Unmarshal(event.Item, &itemHeader) == nil && itemHeader.Type != "" {
+				isCodex = true
+			}
+		}
 		isClaude := event.Subtype != "" || event.Result != ""
-		isGemini := event.Role != "" || event.Delta
+		isGemini := event.Role != "" || event.Delta != nil || event.Status != ""
 
 		// Handle Codex events
 		if isCodex {
@@ -159,18 +167,6 @@ func parseJSONStreamInternal(r io.Reader, warnFn func(string), infoFn func(strin
 				details = append(details, fmt.Sprintf("thread_id=%s", event.ThreadID))
 			}
 
-			// Parse item type if present
-			var itemType string
-			if len(event.Item) > 0 {
-				var itemHeader struct {
-					Type string `json:"type"`
-				}
-				if err := json.Unmarshal(event.Item, &itemHeader); err == nil {
-					itemType = itemHeader.Type
-					details = append(details, fmt.Sprintf("item_type=%s", itemType))
-				}
-			}
-
 			if len(details) > 0 {
 				infoFn(fmt.Sprintf("Parsed event #%d type=%s (%s)", totalEvents, event.Type, strings.Join(details, ", ")))
 			} else {
@@ -183,6 +179,16 @@ func parseJSONStreamInternal(r io.Reader, warnFn func(string), infoFn func(strin
 				infoFn(fmt.Sprintf("thread.started event thread_id=%s", threadID))
 
 			case "item.completed":
+				var itemType string
+				if len(event.Item) > 0 {
+					var itemHeader struct {
+						Type string `json:"type"`
+					}
+					if err := json.Unmarshal(event.Item, &itemHeader); err == nil {
+						itemType = itemHeader.Type
+					}
+				}
+
 				if itemType == "agent_message" && len(event.Item) > 0 {
 					// Lazy parse: only parse item content when needed
 					var item ItemContent
@@ -226,10 +232,18 @@ func parseJSONStreamInternal(r io.Reader, warnFn func(string), infoFn func(strin
 
 			if event.Content != "" {
 				geminiBuffer.WriteString(event.Content)
+			}
+
+			if event.Status != "" {
 				notifyMessage()
 			}
 
-			infoFn(fmt.Sprintf("Parsed Gemini event #%d type=%s role=%s delta=%t status=%s content_len=%d", totalEvents, event.Type, event.Role, event.Delta, event.Status, len(event.Content)))
+			delta := false
+			if event.Delta != nil {
+				delta = *event.Delta
+			}
+
+			infoFn(fmt.Sprintf("Parsed Gemini event #%d type=%s role=%s delta=%t status=%s content_len=%d", totalEvents, event.Type, event.Role, delta, event.Status, len(event.Content)))
 			continue
 		}