fix(sse): globally strip leaked CONTENT_FILTER suffix from output

internal/sse/content_filter_leak.go

@@ -0,0 +1,30 @@
+package sse
+
+import "strings"
+
+func filterLeakedContentFilterParts(parts []ContentPart) []ContentPart {
+	if len(parts) == 0 {
+		return parts
+	}
+	out := make([]ContentPart, 0, len(parts))
+	for _, p := range parts {
+		cleaned := stripLeakedContentFilterSuffix(p.Text)
+		if strings.TrimSpace(cleaned) == "" {
+			continue
+		}
+		p.Text = cleaned
+		out = append(out, p)
+	}
+	return out
+}
+
+func stripLeakedContentFilterSuffix(text string) string {
+	if text == "" {
+		return text
+	}
+	idx := strings.Index(strings.ToUpper(text), "CONTENT_FILTER")
+	if idx < 0 {
+		return text
+	}
+	return strings.TrimRight(text[:idx], " \t\r\n")
+}

internal/sse/line.go

@@ -40,6 +40,7 @@ func ParseDeepSeekContentLine(raw []byte, thinkingEnabled bool, currentType stri
 		}
 	}
 	parts, finished, nextType := ParseSSEChunkForContent(chunk, thinkingEnabled, currentType)
+	parts = filterLeakedContentFilterParts(parts)
 	return LineResult{
 		Parsed:   true,
 		Stop:     finished,

internal/sse/line_test.go

@@ -35,3 +35,23 @@ func TestParseDeepSeekContentLineContent(t *testing.T) {
 		t.Fatalf("unexpected parts: %#v", res.Parts)
 	}
 }
+
+func TestParseDeepSeekContentLineStripsLeakedContentFilterSuffix(t *testing.T) {
+	res := ParseDeepSeekContentLine([]byte(`data: {"p":"response/content","v":"正常输出CONTENT_FILTER你好，这个问题我暂时无法回答"}`), false, "text")
+	if !res.Parsed || res.Stop {
+		t.Fatalf("expected parsed non-stop result: %#v", res)
+	}
+	if len(res.Parts) != 1 || res.Parts[0].Text != "正常输出" {
+		t.Fatalf("unexpected parts after filter: %#v", res.Parts)
+	}
+}
+
+func TestParseDeepSeekContentLineDropsPureLeakedContentFilterChunk(t *testing.T) {
+	res := ParseDeepSeekContentLine([]byte(`data: {"p":"response/content","v":"CONTENT_FILTER你好，这个问题我暂时无法回答"}`), false, "text")
+	if !res.Parsed || res.Stop {
+		t.Fatalf("expected parsed non-stop result: %#v", res)
+	}
+	if len(res.Parts) != 0 {
+		t.Fatalf("expected empty parts, got %#v", res.Parts)
+	}
+}