diff --git a/cmd/campaigns.go b/cmd/campaigns.go
index 468105d..14739ce 100644
--- a/cmd/campaigns.go
+++ b/cmd/campaigns.go
@@ -53,10 +53,11 @@ func addCampaignFieldFlags(cmd *cobra.Command) {
 	cmd.Flags().String("campaign-group-id", "", "Campaign group ID")
 	cmd.Flags().String("mailing-list-id", "", `Mailing list ID to target. Pass "null" to clear.`)
 	cmd.Flags().String("audience-segment-id", "", `Audience segment ID to target. Pass "null" to clear.`)
-	cmd.Flags().String("audience-filter-file", "", `Path to a JSON file with an ad-hoc audience filter. Pass "null" to clear.`)
+	cmd.Flags().String("audience-filter", "", `Inline JSON string with an ad-hoc audience filter. Pass "null" to clear.`)
+	cmd.Flags().String("audience-filter-file", "", "Path to a JSON file with an ad-hoc audience filter")
 	cmd.Flags().Bool("schedule-now", false, "Send immediately when published")
 	cmd.Flags().String("schedule-at", "", "Send at the given ISO 8601 timestamp (e.g. 2026-07-01T12:00:00Z)")
-	cmd.MarkFlagsMutuallyExclusive("audience-segment-id", "audience-filter-file")
+	cmd.MarkFlagsMutuallyExclusive("audience-segment-id", "audience-filter", "audience-filter-file")
 	cmd.MarkFlagsMutuallyExclusive("schedule-now", "schedule-at")
 }
 
@@ -76,6 +77,56 @@ func readNullableFlag(cmd *cobra.Command, flagName string) (*string, bool, error
 	return &v, true, nil
 }
 
+// resolveAudienceFilter reads the ad-hoc audience filter from either the inline
+// --audience-filter JSON string or the --audience-filter-file path and returns
+// (filterOrNil, set, err). At most one flag may be provided; the mutual
+// exclusion is also checked here (not just via cobra's flag group) so it holds
+// when RunE is invoked directly in tests.
+//
+// Only --audience-filter accepts the "null" sentinel to clear the field,
+// encoded as a nil filter with set=true. --audience-filter-file always names a
+// file, so a non-file value simply fails the read.
+func resolveAudienceFilter(cmd *cobra.Command) (*loops.AudienceFilter, bool, error) {
+	inlineSet := cmd.Flags().Changed("audience-filter")
+	fileSet := cmd.Flags().Changed("audience-filter-file")
+	switch {
+	case !inlineSet && !fileSet:
+		return nil, false, nil
+	case inlineSet && fileSet:
+		return nil, false, fmt.Errorf("--audience-filter and --audience-filter-file are mutually exclusive")
+	}
+
+	src := "--audience-filter"
+	var data []byte
+	if inlineSet {
+		v, _ := cmd.Flags().GetString("audience-filter")
+		if v == "" {
+			return nil, false, fmt.Errorf(`--audience-filter requires a value; pass "null" to clear`)
+		}
+		if v == nullSentinel {
+			return nil, true, nil
+		}
+		data = []byte(v)
+	} else {
+		src = "--audience-filter-file"
+		path, _ := cmd.Flags().GetString("audience-filter-file")
+		if path == "" {
+			return nil, false, fmt.Errorf("--audience-filter-file requires a file path")
+		}
+		b, err := os.ReadFile(path)
+		if err != nil {
+			return nil, false, fmt.Errorf("read --audience-filter-file: %w", err)
+		}
+		data = b
+	}
+
+	var f loops.AudienceFilter
+	if err := json.Unmarshal(data, &f); err != nil {
+		return nil, false, fmt.Errorf("parse %s: %w", src, err)
+	}
+	return &f, true, nil
+}
+
 func campaignFieldParamsFromCmd(cmd *cobra.Command) (campaignFieldParams, error) {
 	p := campaignFieldParams{Set: map[string]bool{}}
 
@@ -99,26 +150,11 @@ func campaignFieldParamsFromCmd(cmd *cobra.Command) (campaignFieldParams, error)
 		p.AudienceSegmentID = v
 		p.Set["audienceSegmentId"] = true
 	}
-	if cmd.Flags().Changed("audience-filter-file") {
-		path, _ := cmd.Flags().GetString("audience-filter-file")
-		if path == "" {
-			return p, fmt.Errorf(`--audience-filter-file requires a value; pass "null" to clear`)
-		}
-		if path == nullSentinel {
-			p.AudienceFilter = nil
-			p.Set["audienceFilter"] = true
-		} else {
-			data, err := os.ReadFile(path)
-			if err != nil {
-				return p, fmt.Errorf("read --audience-filter-file: %w", err)
-			}
-			var f loops.AudienceFilter
-			if err := json.Unmarshal(data, &f); err != nil {
-				return p, fmt.Errorf("parse --audience-filter-file: %w", err)
-			}
-			p.AudienceFilter = &f
-			p.Set["audienceFilter"] = true
-		}
+	if f, set, err := resolveAudienceFilter(cmd); err != nil {
+		return p, err
+	} else if set {
+		p.AudienceFilter = f
+		p.Set["audienceFilter"] = true
 	}
 	if cmd.Flags().Changed("schedule-now") {
 		p.Scheduling = &loops.CampaignSchedulingRequest{Method: loops.CampaignSchedulingMethodNow}
@@ -352,6 +388,7 @@ func init() {
 		"campaign-group-id",
 		"mailing-list-id",
 		"audience-segment-id",
+		"audience-filter",
 		"audience-filter-file",
 		"schedule-now",
 		"schedule-at",
diff --git a/cmd/campaigns_fields_test.go b/cmd/campaigns_fields_test.go
index d08abd8..a0d824a 100644
--- a/cmd/campaigns_fields_test.go
+++ b/cmd/campaigns_fields_test.go
@@ -143,6 +143,98 @@ func TestCampaignFieldParamsFromCmd(t *testing.T) {
 		}
 	})
 
+	t.Run("audience-filter parses inline JSON", func(t *testing.T) {
+		cmd := newCampaignFieldCmd()
+		filter := `{"match":"any","conditions":[{"type":"property","key":"plan","operator":"equals","value":"pro"}]}`
+		if err := cmd.ParseFlags([]string{"--audience-filter", filter}); err != nil {
+			t.Fatalf("ParseFlags: %v", err)
+		}
+		p, err := campaignFieldParamsFromCmd(cmd)
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if p.AudienceFilter == nil {
+			t.Fatal("AudienceFilter nil")
+		}
+		if p.AudienceFilter.Match != "any" {
+			t.Errorf("Match = %q, want any", p.AudienceFilter.Match)
+		}
+		if len(p.AudienceFilter.Conditions) != 1 {
+			t.Fatalf("Conditions len = %d, want 1", len(p.AudienceFilter.Conditions))
+		}
+		if p.AudienceFilter.Conditions[0].Type != loops.AudienceConditionTypeProperty {
+			t.Errorf("Conditions[0].Type = %q", p.AudienceFilter.Conditions[0].Type)
+		}
+		if !p.Set["audienceFilter"] {
+			t.Error(`Set["audienceFilter"] = false, want true`)
+		}
+	})
+
+	t.Run("audience-filter invalid JSON returns error", func(t *testing.T) {
+		cmd := newCampaignFieldCmd()
+		if err := cmd.ParseFlags([]string{"--audience-filter", "{not json"}); err != nil {
+			t.Fatalf("ParseFlags: %v", err)
+		}
+		_, err := campaignFieldParamsFromCmd(cmd)
+		if err == nil {
+			t.Fatal("expected error, got nil")
+		}
+		if !strings.Contains(err.Error(), "parse --audience-filter:") {
+			t.Errorf("error = %q, want a %q parse error", err.Error(), "parse --audience-filter:")
+		}
+	})
+
+	t.Run("audience-filter-file invalid JSON returns error", func(t *testing.T) {
+		dir := t.TempDir()
+		path := filepath.Join(dir, "filter.json")
+		if err := os.WriteFile(path, []byte("{not json"), 0o600); err != nil {
+			t.Fatalf("write fixture: %v", err)
+		}
+
+		cmd := newCampaignFieldCmd()
+		if err := cmd.ParseFlags([]string{"--audience-filter-file", path}); err != nil {
+			t.Fatalf("ParseFlags: %v", err)
+		}
+		_, err := campaignFieldParamsFromCmd(cmd)
+		if err == nil {
+			t.Fatal("expected error, got nil")
+		}
+		if !strings.Contains(err.Error(), "parse --audience-filter-file:") {
+			t.Errorf("error = %q, want a %q parse error", err.Error(), "parse --audience-filter-file:")
+		}
+	})
+
+	t.Run(`audience-filter "null" sentinel clears the filter`, func(t *testing.T) {
+		cmd := newCampaignFieldCmd()
+		if err := cmd.ParseFlags([]string{"--audience-filter", "null"}); err != nil {
+			t.Fatalf("ParseFlags: %v", err)
+		}
+		p, err := campaignFieldParamsFromCmd(cmd)
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if p.AudienceFilter != nil {
+			t.Errorf("AudienceFilter = %v, want nil", p.AudienceFilter)
+		}
+		if !p.Set["audienceFilter"] {
+			t.Error(`Set["audienceFilter"] = false, want true`)
+		}
+	})
+
+	t.Run("audience-filter and audience-filter-file together return error", func(t *testing.T) {
+		cmd := newCampaignFieldCmd()
+		if err := cmd.ParseFlags([]string{"--audience-filter", "{}", "--audience-filter-file", "f.json"}); err != nil {
+			t.Fatalf("ParseFlags: %v", err)
+		}
+		_, err := campaignFieldParamsFromCmd(cmd)
+		if err == nil {
+			t.Fatal("expected error, got nil")
+		}
+		if !strings.Contains(err.Error(), "mutually exclusive") {
+			t.Errorf("error = %q, want it to mention mutually exclusive", err.Error())
+		}
+	})
+
 	t.Run("audience-filter-file missing returns error", func(t *testing.T) {
 		cmd := newCampaignFieldCmd()
 		if err := cmd.ParseFlags([]string{"--audience-filter-file", "/no/such/file.json"}); err != nil {
@@ -187,25 +279,22 @@ func TestCampaignFieldParamsFromCmd(t *testing.T) {
 		}
 	})
 
-	t.Run(`audience-filter-file "null" sentinel clears the filter`, func(t *testing.T) {
+	t.Run(`audience-filter-file "null" is treated as a path, not a clear`, func(t *testing.T) {
 		cmd := newCampaignFieldCmd()
 		if err := cmd.ParseFlags([]string{"--audience-filter-file", "null"}); err != nil {
 			t.Fatalf("ParseFlags: %v", err)
 		}
-		p, err := campaignFieldParamsFromCmd(cmd)
-		if err != nil {
-			t.Fatalf("unexpected error: %v", err)
-		}
-		if p.AudienceFilter != nil {
-			t.Errorf("AudienceFilter = %v, want nil", p.AudienceFilter)
+		_, err := campaignFieldParamsFromCmd(cmd)
+		if err == nil {
+			t.Fatal("expected error reading file \"null\", got nil")
 		}
-		if !p.Set["audienceFilter"] {
-			t.Error(`Set["audienceFilter"] = false, want true`)
+		if !strings.Contains(err.Error(), "read --audience-filter-file") {
+			t.Errorf("error = %q, want a file-read error", err.Error())
 		}
 	})
 
-	t.Run("empty value on nullable flag is rejected", func(t *testing.T) {
-		cases := []string{"mailing-list-id", "audience-segment-id", "audience-filter-file"}
+	t.Run("empty value on nullable string flag is rejected", func(t *testing.T) {
+		cases := []string{"mailing-list-id", "audience-segment-id", "audience-filter"}
 		for _, flag := range cases {
 			t.Run(flag, func(t *testing.T) {
 				cmd := newCampaignFieldCmd()
@@ -222,4 +311,18 @@ func TestCampaignFieldParamsFromCmd(t *testing.T) {
 			})
 		}
 	})
+
+	t.Run("empty audience-filter-file is rejected", func(t *testing.T) {
+		cmd := newCampaignFieldCmd()
+		if err := cmd.ParseFlags([]string{"--audience-filter-file", ""}); err != nil {
+			t.Fatalf("ParseFlags: %v", err)
+		}
+		_, err := campaignFieldParamsFromCmd(cmd)
+		if err == nil {
+			t.Fatal("expected error, got nil")
+		}
+		if !strings.Contains(err.Error(), "file path") {
+			t.Errorf("error = %q, want it to mention a file path", err.Error())
+		}
+	})
 }
diff --git a/cmd/campaigns_update_test.go b/cmd/campaigns_update_test.go
index 27a70ff..9a23310 100644
--- a/cmd/campaigns_update_test.go
+++ b/cmd/campaigns_update_test.go
@@ -67,6 +67,29 @@ func TestRunCampaignsUpdate(t *testing.T) {
 		}
 	})
 
+	t.Run("cleared audienceFilter sends JSON null on the wire", func(t *testing.T) {
+		got := serveJSONCapture(t, http.StatusOK, body)
+		_, err := runCampaignsUpdate(cfg(t), "cmp_abc123", loops.UpdateCampaignRequest{
+			AudienceFilter: nil,
+			Set:            map[string]bool{"audienceFilter": true},
+		})
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+
+		var sent map[string]any
+		if err := json.Unmarshal(got.Body, &sent); err != nil {
+			t.Fatalf("decode request body: %v\nraw: %s", err, got.Body)
+		}
+		v, ok := sent["audienceFilter"]
+		if !ok {
+			t.Fatalf("audienceFilter missing from request body: %v", sent)
+		}
+		if v != nil {
+			t.Errorf("audienceFilter = %v, want nil (JSON null)", v)
+		}
+	})
+
 	t.Run("Set map controls which fields are sent", func(t *testing.T) {
 		got := serveJSONCapture(t, http.StatusOK, body)
 		ts := "2026-07-01T12:00:00Z"