fix: select thread id for deduped trace listing

Author: paarth-a

internal/cmd/helpers.go

@@ -117,6 +117,14 @@ func buildRunSelect(includeIO, includeFeedback bool) []langsmith.RunQueryParamsS
 		return nil
 	}
 
+	return buildRunSelectFields(includeIO, includeFeedback)
+}
+
+func buildRunSelectWithThreadID(includeIO, includeFeedback bool) []langsmith.RunQueryParamsSelect {
+	return appendRunSelect(buildRunSelectFields(includeIO, includeFeedback), langsmith.RunQueryParamsSelectThreadID)
+}
+
+func buildRunSelectFields(includeIO, includeFeedback bool) []langsmith.RunQueryParamsSelect {
 	fields := []langsmith.RunQueryParamsSelect{
 		// Base fields
 		langsmith.RunQueryParamsSelectID,
@@ -155,6 +163,15 @@ func buildRunSelect(includeIO, includeFeedback bool) []langsmith.RunQueryParamsS
 	return fields
 }
 
+func appendRunSelect(fields []langsmith.RunQueryParamsSelect, field langsmith.RunQueryParamsSelect) []langsmith.RunQueryParamsSelect {
+	for _, existing := range fields {
+		if existing == field {
+			return fields
+		}
+	}
+	return append(fields, field)
+}
+
 // extractRunsToMaps extracts a slice of runs to maps.
 func extractRunsToMaps(runs []langsmith.RunSchema, includeMetadata, includeIO, includeFeedback bool) []map[string]any {
 	result := make([]map[string]any, 0, len(runs))

internal/cmd/trace.go

@@ -74,12 +74,9 @@ func newTraceListCmd() *cobra.Command {
 			}
 
 			params := BuildRunQueryParams(&ff, true, ff.Limit)
-			if sel := buildRunSelect(includeIO, includeFeedback); sel != nil {
-				// When de-duping by thread, thread_id must be selected so it
-				// is present on the returned runs.
-				if onePerThread {
-					sel = append(sel, langsmith.RunQueryParamsSelectThreadID)
-				}
+			if onePerThread {
+				params.Select = langsmith.F(buildRunSelectWithThreadID(includeIO, includeFeedback))
+			} else if sel := buildRunSelect(includeIO, includeFeedback); sel != nil {
 				params.Select = langsmith.F(sel)
 			}
 			var runs []langsmith.RunSchema

internal/cmd/trace_test.go

@@ -171,6 +171,26 @@ func traceRunWithTokens(id, traceID, threadID, startTime string, totalTokens int
 	return run
 }
 
+func requireSelectContains(t *testing.T, body map[string]any, expected ...string) {
+	t.Helper()
+
+	selects, ok := body["select"].([]any)
+	if !ok {
+		t.Fatalf("expected select array in request, got %#v", body["select"])
+	}
+	seen := make(map[string]bool, len(selects))
+	for _, sel := range selects {
+		if s, ok := sel.(string); ok {
+			seen[s] = true
+		}
+	}
+	for _, field := range expected {
+		if !seen[field] {
+			t.Fatalf("expected select to include %q, got %#v", field, selects)
+		}
+	}
+}
+
 func TestTraceListCmd_OnePerThreadFlagDefault(t *testing.T) {
 	cmd := newTraceListCmd()
 	f := cmd.Flags().Lookup("one-per-thread")
@@ -291,6 +311,31 @@ func TestTraceListCmd_OnePerThreadAppliesMinTokensBeforeDedupe(t *testing.T) {
 	}
 }
 
+func TestTraceListCmd_OnePerThreadSelectsThreadIDWithoutIncludeFlags(t *testing.T) {
+	var requests []map[string]any
+	ts := newTraceListPagingServer(t, []traceListPage{{
+		runs: []map[string]any{
+			traceRun("run-a", "trace-a", "thread-a", "2026-01-01T00:00:00Z"),
+		},
+	}}, &requests)
+
+	_ = runTraceListJSON(t, ts.URL, "--one-per-thread", "--limit", "1")
+
+	if len(requests) != 1 {
+		t.Fatalf("expected 1 run query request, got %d", len(requests))
+	}
+	requireSelectContains(t, requests[0],
+		"id",
+		"trace_id",
+		"name",
+		"run_type",
+		"parent_run_id",
+		"start_time",
+		"end_time",
+		"thread_id",
+	)
+}
+
 func TestTraceListCmd_OnePerThreadIncludeIOSelectsThreadID(t *testing.T) {
 	var requests []map[string]any
 	ts := newTraceListPagingServer(t, []traceListPage{{
@@ -304,16 +349,7 @@ func TestTraceListCmd_OnePerThreadIncludeIOSelectsThreadID(t *testing.T) {
 	if len(requests) != 1 {
 		t.Fatalf("expected 1 run query request, got %d", len(requests))
 	}
-	selects, ok := requests[0]["select"].([]any)
-	if !ok {
-		t.Fatalf("expected select array in request, got %#v", requests[0]["select"])
-	}
-	for _, sel := range selects {
-		if sel == "thread_id" {
-			return
-		}
-	}
-	t.Fatalf("expected select to include thread_id, got %#v", selects)
+	requireSelectContains(t, requests[0], "thread_id", "inputs", "outputs", "error")
 }
 
 // ==================== trace get flags ====================