Order spell and NPC extraction by document position

internal/modules/dnd/extract/npcs/extractor_test.go

@@ -84,6 +84,43 @@ func TestExtractOrdersNPCsBySourcePositionRatherThanUnitID(t *testing.T) {
 	}
 }
 
+func TestExtractUsesDocumentOrderForNPCReferencesAndStableTies(t *testing.T) {
+	client := &fakeNPCsLLMClient{response: extractionResponse{NPCs: []npcResponse{
+		{Name: "Later", SourceRefs: responseSourceRefs(10, 10)},
+		{Name: "First", SourceRefs: []npcSourceRefResponse{
+			{StartUnitID: 10, EndUnitID: 10},
+			{StartUnitID: 30, EndUnitID: 30},
+			{StartUnitID: 30, EndUnitID: 30},
+			{StartUnitID: 999, EndUnitID: 0},
+		}},
+		{Name: "Second", SourceRefs: responseSourceRefs(30, 30)},
+	}}}
+	req := extractionRequest()
+	req.Source.Units = []source.SourceUnit{{ID: 30}, {ID: 10}}
+	req.Chunk.Units = append([]source.SourceUnit(nil), req.Source.Units...)
+	req.Chunk.Ref = source.SourceRef{SourceID: req.Source.ID, StartUnitID: 30, EndUnitID: 10}
+
+	result, err := newExtractor(t, client).Extract(context.Background(), req)
+	if err != nil {
+		t.Fatalf("Extract() error = %v", err)
+	}
+	if got := []string{result.Value.NPCs[0].Name, result.Value.NPCs[1].Name, result.Value.NPCs[2].Name}; !reflect.DeepEqual(got, []string{"First", "Second", "Later"}) {
+		t.Fatalf("NPC order = %#v, want document chronology with stable equal-evidence ties", got)
+	}
+	refs := result.Value.NPCs[0].SourceRefs
+	if got := []int{refs[0].StartUnitID, refs[1].StartUnitID, refs[2].StartUnitID}; !reflect.DeepEqual(got, []int{30, 10, 999}) {
+		t.Fatalf("source refs = %#v, want document order with exact duplicate removed", refs)
+	}
+	refs[0].StartUnitID = 777
+	for _, npc := range client.response.NPCs {
+		for _, ref := range npc.SourceRefs {
+			if ref.StartUnitID == 777 {
+				t.Fatal("result source references alias the model response")
+			}
+		}
+	}
+}
+
 func TestExtractPassesCampaignReferencesAsPromptInputs(t *testing.T) {
 	client := &fakeNPCsLLMClient{response: extractionResponse{NPCs: []npcResponse{}}}
 	req := extractionRequest()