diff --git a/cmd/internal-tools/analyze/end_to_end_test.go b/cmd/internal-tools/analyze/end_to_end_test.go
index effe935..9278e42 100644
--- a/cmd/internal-tools/analyze/end_to_end_test.go
+++ b/cmd/internal-tools/analyze/end_to_end_test.go
@@ -258,3 +258,55 @@ func TestRun_RequiresACampaignDirectory(t *testing.T) {
 		t.Fatal("expected an error with no campaign directories")
 	}
 }
+
+// A campaign recorded before actions named their producer cannot say whether
+// the login taps of the spec's setup are inside its per-action denominator, and
+// the report has to say so where that denominator is read rather than leave the
+// reader to date the file.
+func TestRun_MarksAnArmWhoseActionsNameNoProducer(t *testing.T) {
+	root := t.TempDir()
+	directory := filepath.Join(root, "before-source")
+	buildFixtureCampaign(t, directory, "before-source", 30, []map[string]any{
+		{"seed": 1, "exit_code": 0, "steps": 30, "actions": 28, "duration_millis": 60000},
+		{"seed": 2, "exit_code": 0, "steps": 9, "actions": 9, "duration_millis": 60000,
+			"first_violation_origin_step": 9, "violated_properties": []string{"cartTotalMatches"}},
+	})
+
+	var stdout bytes.Buffer
+	if err := run([]string{"--json", "-", directory}, &stdout, io.Discard); err != nil {
+		t.Fatal(err)
+	}
+	text := stdout.String()
+	if !strings.Contains(text, "37 (37 unattributed)") {
+		t.Errorf("the actions cell does not carry the unattributed count\n%s", text)
+	}
+	if !strings.Contains(text, "unknown provenance") {
+		t.Errorf("the report does not say the denominator's provenance is unknown\n%s", text)
+	}
+
+	var result analysis
+	if err := json.Unmarshal([]byte(text[strings.Index(text, "{"):]), &result); err != nil {
+		t.Fatalf("json: %v", err)
+	}
+	if len(result.Arms) != 1 || result.Arms[0].UnattributedActions != 37 {
+		t.Errorf("arms %+v, want 37 unattributed actions", result.Arms)
+	}
+}
+
+func TestRun_LeavesAnArmWhoseActionsAllNameAProducerUnmarked(t *testing.T) {
+	root := t.TempDir()
+	directory := filepath.Join(root, "sourced")
+	buildFixtureCampaign(t, directory, "sourced", 30, []map[string]any{
+		{"seed": 1, "exit_code": 0, "steps": 30, "actions": 28, "duration_millis": 60000, "unattributed_actions": 0},
+		{"seed": 2, "exit_code": 0, "steps": 9, "actions": 9, "duration_millis": 60000, "unattributed_actions": 0,
+			"first_violation_origin_step": 9, "violated_properties": []string{"cartTotalMatches"}},
+	})
+
+	var stdout bytes.Buffer
+	if err := run([]string{directory}, &stdout, io.Discard); err != nil {
+		t.Fatal(err)
+	}
+	if strings.Contains(stdout.String(), "unattributed") || strings.Contains(stdout.String(), "unknown provenance") {
+		t.Errorf("an arm whose every action names a producer was marked\n%s", stdout.String())
+	}
+}
diff --git a/cmd/internal-tools/analyze/report.go b/cmd/internal-tools/analyze/report.go
index dfa6773..c47d5aa 100644
--- a/cmd/internal-tools/analyze/report.go
+++ b/cmd/internal-tools/analyze/report.go
@@ -42,7 +42,7 @@ func writeReport(result analysis, out io.Writer) {
 				add(
 					summary.Arm,
 					strconv.Itoa(summary.TotalSteps),
-					strconv.Itoa(summary.TotalActions),
+					formatActions(summary),
 					fmt.Sprintf("%.2f", summary.TotalRunHours),
 					strconv.Itoa(summary.Detections),
 					formatRatio(summary.DefectsPerThousandActions, 2),
@@ -64,6 +64,13 @@ func writeReport(result analysis, out io.Writer) {
 		fmt.Fprintf(out, "\n%s excluded %d run(s) as missing data, not as censored observations: %s",
 			summary.Arm, summary.Excluded, strings.Join(parts, ", "))
 	}
+	for _, summary := range result.Arms {
+		if summary.UnattributedActions > 0 {
+			fmt.Fprintf(out, "\n%s counts %d action(s) of unknown provenance, recorded before an action named its producer: "+
+				"its per-action denominator may include the login the spec's setup drove",
+				summary.Arm, summary.UnattributedActions)
+		}
+	}
 	for _, summary := range result.Arms {
 		if summary.EventsHeldAtBudget > 0 {
 			fmt.Fprintf(out, "\n%s held %d violation(s) reported past the budget at %d steps",
@@ -168,6 +175,16 @@ func formatMedian(value *float64) string {
 	return strconv.FormatFloat(*value, 'f', -1, 64)
 }
 
+// formatActions marks a denominator with actions whose producer nothing names,
+// because the rate beside it then divides by a count that may include the
+// login the spec's setup drove.
+func formatActions(summary armSummary) string {
+	if summary.UnattributedActions == 0 {
+		return strconv.Itoa(summary.TotalActions)
+	}
+	return fmt.Sprintf("%d (%d unattributed)", summary.TotalActions, summary.UnattributedActions)
+}
+
 func formatRatio(value *float64, digits int) string {
 	if value == nil {
 		return "n/a"