diff --git a/internal/lidarr/client.go b/internal/lidarr/client.go
index 3c6b7d4b..9d90cc51 100644
--- a/internal/lidarr/client.go
+++ b/internal/lidarr/client.go
@@ -274,13 +274,20 @@ func (c *Client) LookupTrack(ctx context.Context, term string) ([]LookupResult,
 	return out, nil
 }
 
-// AddArtist posts to POST /api/v1/artist. MonitorAll=true sends monitor="all";
-// false sends "future". Returns nil on 2xx; typed error otherwise.
+// AddArtist posts to POST /api/v1/artist. MonitorAll=true monitors every
+// album ("all"); false monitors only releases from now on ("future"). New
+// releases are monitored either way. Returns nil on 2xx; typed error
+// otherwise.
 //
 // All four of artistName, foreignArtistId, qualityProfileId, and
 // metadataProfileId are required by Lidarr. Omitting any one produces a
 // 400 with field-level validation messages (e.g. "'Metadata Profile Id'
 // must be greater than '0'").
+//
+// The monitor choice belongs in addOptions (AddArtistOptions, a
+// MonitoringOptions). ArtistResource has no top-level `monitor`, so a
+// choice sent there is dropped, AddOptions.Monitor stays Unknown and
+// Lidarr skips applying it (#5239).
 func (c *Client) AddArtist(ctx context.Context, p AddArtistParams) error {
 	monitor := "future"
 	if p.MonitorAll {
@@ -293,8 +300,12 @@ func (c *Client) AddArtist(ctx context.Context, p AddArtistParams) error {
 		"metadataProfileId": p.MetadataProfileID,
 		"rootFolderPath":    p.RootFolderPath,
 		"monitored":         true,
-		"monitor":           monitor,
-		"addOptions":        map[string]any{"searchForMissingAlbums": true},
+		"monitorNewItems":   "all",
+		"addOptions": map[string]any{
+			"monitor":                monitor,
+			"monitored":              true,
+			"searchForMissingAlbums": true,
+		},
 	})
 	if err != nil {
 		return fmt.Errorf("%w: marshal: %v", ErrInvalidPayload, err)
diff --git a/internal/lidarr/client_test.go b/internal/lidarr/client_test.go
index c797af00..43e7b0af 100644
--- a/internal/lidarr/client_test.go
+++ b/internal/lidarr/client_test.go
@@ -288,13 +288,24 @@ func TestAddArtist_PostsCorrectBody(t *testing.T) {
 	if decoded["monitored"] != true {
 		t.Errorf("monitored = %v, want true", decoded["monitored"])
 	}
-	if decoded["monitor"] != "all" {
-		t.Errorf("monitor = %v, want all (MonitorAll=true)", decoded["monitor"])
+	if decoded["monitorNewItems"] != "all" {
+		t.Errorf("monitorNewItems = %v, want all", decoded["monitorNewItems"])
+	}
+	// #5239: ArtistResource has no top-level monitor; Lidarr reads the
+	// choice from addOptions and silently drops it anywhere else.
+	if _, set := decoded["monitor"]; set {
+		t.Errorf("monitor sent at top level (%v), where Lidarr ignores it", decoded["monitor"])
 	}
 	opts, ok := decoded["addOptions"].(map[string]any)
 	if !ok {
 		t.Fatalf("addOptions missing or wrong type: %T", decoded["addOptions"])
 	}
+	if opts["monitor"] != "all" {
+		t.Errorf("addOptions.monitor = %v, want all (MonitorAll=true)", opts["monitor"])
+	}
+	if opts["monitored"] != true {
+		t.Errorf("addOptions.monitored = %v, want true", opts["monitored"])
+	}
 	if opts["searchForMissingAlbums"] != true {
 		t.Errorf("addOptions.searchForMissingAlbums = %v, want true", opts["searchForMissingAlbums"])
 	}
@@ -309,8 +320,8 @@ func TestAddArtist_MonitorFuture(t *testing.T) {
 	defer srv.Close()
 
 	_ = c.AddArtist(context.Background(), AddArtistParams{MonitorAll: false})
-	if decoded["monitor"] != "future" {
-		t.Errorf("monitor = %v, want future (MonitorAll=false)", decoded["monitor"])
+	if opts, _ := decoded["addOptions"].(map[string]any); opts["monitor"] != "future" {
+		t.Errorf("addOptions.monitor = %v, want future (MonitorAll=false)", opts["monitor"])
 	}
 }
 
diff --git a/internal/lidarr/types.go b/internal/lidarr/types.go
index 7a5858f7..3fd9db36 100644
--- a/internal/lidarr/types.go
+++ b/internal/lidarr/types.go
@@ -57,7 +57,7 @@ type AddArtistParams struct {
 	QualityProfileID  int
 	MetadataProfileID int
 	RootFolderPath    string
-	MonitorAll        bool // true => monitor="all"; false => "future"
+	MonitorAll        bool // true => addOptions.monitor="all"; false => "future"
 }
 
 // AddAlbumParams identify the album to add and carry the settings Lidarr