diff --git a/internal/sse/citation_links.go b/internal/sse/citation_links.go
index 17a6dbb..ef744b4 100644
--- a/internal/sse/citation_links.go
+++ b/internal/sse/citation_links.go
@@ -7,14 +7,12 @@ import (
 
 type citationLinkCollector struct {
 	ordered     []string
-	seen        map[string]struct{}
 	explicitRaw map[int]string
 	hasZeroIdx  bool
 }
 
 func newCitationLinkCollector() *citationLinkCollector {
 	return &citationLinkCollector{
-		seen:        map[string]struct{}{},
 		explicitRaw: map[int]string{},
 	}
 }
@@ -129,10 +127,6 @@ func (c *citationLinkCollector) captureURLAndIndex(m map[string]any) {
 }
 
 func (c *citationLinkCollector) addOrdered(url string) {
-	if _, ok := c.seen[url]; ok {
-		return
-	}
-	c.seen[url] = struct{}{}
 	c.ordered = append(c.ordered, url)
 }
 
diff --git a/internal/sse/consumer_edge_test.go b/internal/sse/consumer_edge_test.go
index 9b49788..d720414 100644
--- a/internal/sse/consumer_edge_test.go
+++ b/internal/sse/consumer_edge_test.go
@@ -166,6 +166,25 @@ func TestCollectStreamExtractsCitationLinksForOneBasedIndices(t *testing.T) {
 	}
 }
 
+func TestCollectStreamExtractsCitationLinksWithRepeatedURLsAndNilIndices(t *testing.T) {
+	resp := makeHTTPResponse(
+		"data: {\"p\":\"response/fragments/-1/results\",\"v\":[{\"url\":\"https://example.com/a\",\"cite_index\":null},{\"url\":\"https://example.com/a\",\"cite_index\":null},{\"url\":\"https://example.com/b\",\"cite_index\":null}]}\n" +
+			"data: {\"p\":\"response/content\",\"v\":\"结论[citation:1][citation:2][citation:3]\"}\n" +
+			"data: [DONE]\n",
+	)
+	result := CollectStream(resp, false, false)
+
+	if got := result.CitationLinks[1]; got != "https://example.com/a" {
+		t.Fatalf("expected citation 1 link, got %q", got)
+	}
+	if got := result.CitationLinks[2]; got != "https://example.com/a" {
+		t.Fatalf("expected citation 2 link, got %q", got)
+	}
+	if got := result.CitationLinks[3]; got != "https://example.com/b" {
+		t.Fatalf("expected citation 3 link, got %q", got)
+	}
+}
+
 func TestCollectStreamMultipleThinkingChunks(t *testing.T) {
 	resp := makeHTTPResponse(
 		"data: {\"p\":\"response/thinking_content\",\"v\":\"part1\"}\n" +