feat(campaign): count dispatched actions, not steps

A step where the policy declined has no action, and a step whose action was
never dispatched did nothing. Both were being counted as actions by everything
downstream.

Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX

cmd/internal-tools/campaign/campaign_test.go

@@ -69,6 +69,41 @@ func writeFakeRun(t *testing.T, arguments []string, steps []trace.Step) {
 	writeRunDirectory(t, argumentValue(arguments, "--output"), "20260101-000000", steps)
 }
 
+func TestRunCampaign_RecordsDispatchedActionsNotSteps(t *testing.T) {
+	directory := t.TempDir()
+	configuration := testConfiguration(t, directory, "--seeds", "1")
+
+	executor := versionAnswering(func(_ context.Context, _ string, arguments []string, _ io.Writer) (int, error) {
+		writeFakeRun(t, arguments, []trace.Step{
+			actingStep(1), observedStep(2), skippedActionStep(3, "unresolved_selector"), actingStep(4),
+		})
+		return 0, nil
+	})
+	if err := runCampaign(context.Background(), configuration, executor, io.Discard); err != nil {
+		t.Fatal(err)
+	}
+
+	records := readRecords(t, directory)
+	if len(records) != 1 {
+		t.Fatalf("records: got %d, want 1", len(records))
+	}
+	if records[0].Steps != 4 || records[0].Actions != 2 {
+		t.Errorf("steps %d actions %d, want 4 and 2", records[0].Steps, records[0].Actions)
+	}
+}
+
+// A run that never produced a readable trace still has to carry the field, so
+// analysis can tell a zero-action run from a file written before the count.
+func TestRunRecord_AlwaysCarriesTheActionCount(t *testing.T) {
+	body, err := json.Marshal(runRecord{Seed: 7, TraceError: "no run directory with meta.json"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(string(body), `"actions":0`) {
+		t.Errorf("record %s omits the action count", body)
+	}
+}
+
 func TestRunCampaign_WritesManifestBeforeAnyRun(t *testing.T) {
 	directory := t.TempDir()
 	configuration := testConfiguration(t, directory)

cmd/internal-tools/campaign/summary.go

@@ -19,7 +19,13 @@ const maxTraceLineBytes = 16 * 1024 * 1024
 // traceSummary is everything the analysis needs from one run, so it never has
 // to open trace.jsonl again.
 type traceSummary struct {
-	Steps                      int      `json:"steps"`
+	Steps int `json:"steps"`
+	// Actions counts only the steps that both chose an action and dispatched
+	// it. A step whose policy declined to act, and a step whose chosen action
+	// the runner threw away, changed nothing about the app, so counting either
+	// as an action inflates the denominator of every per-action rate. The
+	// inflation is policy-dependent, so it does not cancel between arms.
+	Actions                    int      `json:"actions"`
 	FirstViolationOriginStep   *int     `json:"first_violation_origin_step"`
 	FirstViolationDetectedStep *int     `json:"first_violation_detected_step"`
 	FirstViolationProperties   []string `json:"first_violation_properties,omitempty"`
@@ -32,9 +38,20 @@ type traceLine struct {
 	Index int `json:"step"`
 	// Hierarchy is read only for its presence: the run-end finalize line is the
 	// one line carrying violations without an observed hierarchy.
-	Hierarchy  json.RawMessage          `json:"hierarchy"`
-	Violations []string                 `json:"violations"`
-	Witnesses  map[string]trace.Witness `json:"witnesses"`
+	Hierarchy json.RawMessage `json:"hierarchy"`
+	// NextAction is read only for its presence: a step that chose no action
+	// carries none at all.
+	NextAction    json.RawMessage          `json:"next_action"`
+	ActionSkipped string                   `json:"action_skipped"`
+	Violations    []string                 `json:"violations"`
+	Witnesses     map[string]trace.Witness `json:"witnesses"`
+}
+
+func dispatchedAction(line traceLine) bool {
+	if line.ActionSkipped != "" {
+		return false
+	}
+	return len(line.NextAction) > 0 && string(line.NextAction) != "null"
 }
 
 // findRunDirectory returns the run directory `sanderling test` created inside
@@ -103,6 +120,9 @@ func summarizeTrace(tracePath string) (traceSummary, error) {
 		if !synthetic && line.Index > summary.Steps {
 			summary.Steps = line.Index
 		}
+		if !synthetic && dispatchedAction(line) {
+			summary.Actions++
+		}
 		for _, property := range line.Violations {
 			violated[property] = true
 			recordViolation(&summary, line, property)

cmd/internal-tools/campaign/summary_test.go

@@ -22,6 +22,18 @@ func observedStep(index int) trace.Step {
 	}
 }
 
+func actingStep(index int) trace.Step {
+	step := observedStep(index)
+	step.NextAction = &trace.Action{Kind: "tap", X: 12, Y: 34}
+	return step
+}
+
+func skippedActionStep(index int, reason string) trace.Step {
+	step := actingStep(index)
+	step.ActionSkipped = reason
+	return step
+}
+
 func writeRunDirectory(t *testing.T, seedDirectory, name string, steps []trace.Step) string {
 	t.Helper()
 	directory := filepath.Join(seedDirectory, name)
@@ -72,6 +84,88 @@ func TestSummarizeRun_CleanRunIsCensored(t *testing.T) {
 	}
 }
 
+func TestSummarizeRun_CountsOnlyStepsThatDispatchedAnAction(t *testing.T) {
+	seedDirectory := t.TempDir()
+	writeRunDirectory(t, seedDirectory, "20260812-090000", []trace.Step{
+		actingStep(1),
+		observedStep(2),
+		actingStep(3),
+		skippedActionStep(4, "no_target"),
+		skippedActionStep(5, "unresolved_selector"),
+		skippedActionStep(6, "missing_key"),
+		skippedActionStep(7, "zero_duration_wait"),
+		skippedActionStep(8, "app_left_foreground"),
+		skippedActionStep(9, "apply_error"),
+		actingStep(10),
+	})
+
+	_, summary, err := summarizeRun(seedDirectory)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if summary.Steps != 10 {
+		t.Errorf("steps: got %d, want 10", summary.Steps)
+	}
+	if summary.Actions != 3 {
+		t.Errorf("actions: got %d, want 3 (one step chose nothing and six were never dispatched)", summary.Actions)
+	}
+}
+
+func TestSummarizeRun_SkipReasonsEachSuppressTheAction(t *testing.T) {
+	for _, reason := range []string{
+		"no_target", "unresolved_selector", "missing_key",
+		"zero_duration_wait", "app_left_foreground", "apply_error",
+	} {
+		seedDirectory := t.TempDir()
+		writeRunDirectory(t, seedDirectory, "20260812-090000", []trace.Step{
+			actingStep(1), skippedActionStep(2, reason),
+		})
+		_, summary, err := summarizeRun(seedDirectory)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if summary.Actions != 1 {
+			t.Errorf("%s: actions got %d, want 1", reason, summary.Actions)
+		}
+	}
+}
+
+func TestSummarizeTrace_NullActionIsNoAction(t *testing.T) {
+	seedDirectory := t.TempDir()
+	directory := writeRunDirectory(t, seedDirectory, "20260812-090000", []trace.Step{observedStep(1)})
+	lines := "{\"step\":1,\"hierarchy\":{},\"next_action\":null}\n" +
+		"{\"step\":2,\"hierarchy\":{},\"next_action\":{\"kind\":\"tap\"},\"action_skipped\":\"\"}\n"
+	if err := os.WriteFile(filepath.Join(directory, "trace.jsonl"), []byte(lines), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	_, summary, err := summarizeRun(seedDirectory)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if summary.Actions != 1 {
+		t.Errorf("actions: got %d, want 1", summary.Actions)
+	}
+}
+
+func TestSummarizeRun_FinalizeLineIsNotAnAction(t *testing.T) {
+	seedDirectory := t.TempDir()
+	finalize := trace.Step{
+		Index:      3,
+		Timestamp:  time.Now().UTC(),
+		NextAction: &trace.Action{Kind: "tap"},
+		Violations: []string{"eventuallySettles"},
+	}
+	writeRunDirectory(t, seedDirectory, "20260812-090000", []trace.Step{actingStep(1), actingStep(2), finalize})
+
+	_, summary, err := summarizeRun(seedDirectory)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if summary.Actions != 2 {
+		t.Errorf("actions: got %d, want 2", summary.Actions)
+	}
+}
+
 func TestSummarizeRun_UsesWitnessOriginNotDetectionStep(t *testing.T) {
 	seedDirectory := t.TempDir()
 	violating := observedStep(9)