diff --git a/core/extdata/provider_similarsongs_test.go b/core/extdata/provider_similarsongs_test.go
new file mode 100644
index 000000000..24e785856
--- /dev/null
+++ b/core/extdata/provider_similarsongs_test.go
@@ -0,0 +1,447 @@
+package extdata
+
+import (
+	"context"
+	"errors"
+
+	"github.com/navidrome/navidrome/conf"
+	"github.com/navidrome/navidrome/core/agents"
+	"github.com/navidrome/navidrome/model"
+	"github.com/navidrome/navidrome/tests"
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+	"github.com/stretchr/testify/mock"
+)
+
+var _ = Describe("Provider - SimilarSongs", func() {
+	var ds model.DataStore
+	var provider Provider
+	var mockAgent *mockSimilarArtistAgent
+	var mockTopAgent agents.ArtistTopSongsRetriever
+	var mockSimilarAgent agents.ArtistSimilarRetriever
+	var agentsCombined Agents
+	var artistRepo *mockSimArtistRepo
+	var mediaFileRepo *mockSimMediaFileRepo
+	var ctx context.Context
+	var originalAgentsConfig string
+
+	BeforeEach(func() {
+		ctx = context.Background()
+
+		// Store the original agents config to restore it later
+		originalAgentsConfig = conf.Server.Agents
+
+		// Setup mocks - Initialize here, but set expectations within each test
+		artistRepo = newMockSimArtistRepo()
+		mediaFileRepo = newMockSimMediaFileRepo()
+
+		ds = &tests.MockDataStore{
+			MockedArtist:    artistRepo,
+			MockedMediaFile: mediaFileRepo,
+		}
+
+		// Clear the agents map to prevent interference from previous tests
+		agents.Map = nil
+
+		// Create a mock agent that implements both required interfaces
+		// Re-initialize mockAgent in each test if necessary, or ensure Calls are cleared
+		mockAgent = &mockSimilarArtistAgent{}
+		mockTopAgent = mockAgent
+		mockSimilarAgent = mockAgent
+
+		// Create a mock for the combined Agents interface
+		agentsCombined = &mockCombinedAgents{
+			topSongsAgent: mockTopAgent,
+			similarAgent:  mockSimilarAgent,
+		}
+
+		// Create the provider instance with our mock Agents implementation
+		provider = NewProvider(ds, agentsCombined)
+	})
+
+	AfterEach(func() {
+		// Restore original config
+		conf.Server.Agents = originalAgentsConfig
+	})
+
+	Describe("SimilarSongs", func() {
+		It("returns similar songs from main artist and similar artists", func() {
+			// --- Test-specific setup ---
+			artist1 := model.Artist{ID: "artist-1", Name: "Artist One"}
+			similarArtist := model.Artist{ID: "artist-3", Name: "Similar Artist"}
+			song1 := model.MediaFile{ID: "song-1", Title: "Song One", ArtistID: "artist-1"}
+			song2 := model.MediaFile{ID: "song-2", Title: "Song Two", ArtistID: "artist-1"}
+			song3 := model.MediaFile{ID: "song-3", Title: "Song Three", ArtistID: "artist-3"}
+
+			// Configure the Get method (needed for GetEntityByID in getArtist)
+			artistRepo.On("Get", "artist-1").Return(&artist1, nil).Maybe()
+			artistRepo.On("Get", "artist-3").Return(&similarArtist, nil).Maybe() // For similar artist lookup if needed
+
+			// Configure the GetAll mock for finding the main artist in getArtist
+			artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+				return opt.Max == 1 && opt.Filters != nil
+			})).Return(model.Artists{artist1}, nil).Once()
+
+			// Setup similar artists response from agent
+			similarAgentsResp := []agents.Artist{
+				{Name: "Similar Artist", MBID: "similar-mbid"},
+			}
+			mockAgent.On("GetSimilarArtists", mock.Anything, "artist-1", "Artist One", "", 15).
+				Return(similarAgentsResp, nil).Once()
+
+			// Setup for mapping similar artists in mapSimilarArtists
+			artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+				// This will match the query for similar artists (no Max limit set by caller)
+				return opt.Max == 0 && opt.Filters != nil
+			})).Return(model.Artists{similarArtist}, nil).Once()
+
+			// Setup Top Songs responses
+			// Main artist songs
+			mockAgent.On("GetArtistTopSongs", mock.Anything, "artist-1", "Artist One", "", mock.Anything).
+				Return([]agents.Song{
+					{Name: "Song One", MBID: "mbid-1"},
+					{Name: "Song Two", MBID: "mbid-2"},
+				}, nil).Once()
+
+			// Similar artist songs
+			mockAgent.On("GetArtistTopSongs", mock.Anything, "artist-3", "Similar Artist", "", mock.Anything).
+				Return([]agents.Song{
+					{Name: "Song Three", MBID: "mbid-3"},
+				}, nil).Once()
+
+			// Setup mediafile repository to find songs by MBID (via GetAll)
+			mediaFileRepo.FindByMBID("mbid-1", song1)
+			mediaFileRepo.FindByMBID("mbid-2", song2)
+			mediaFileRepo.FindByMBID("mbid-3", song3)
+			// --- End Test-specific setup ---
+
+			songs, err := provider.SimilarSongs(ctx, "artist-1", 3)
+
+			Expect(err).ToNot(HaveOccurred())
+			Expect(songs).To(HaveLen(3))
+			for _, song := range songs {
+				Expect(song.ID).To(BeElementOf("song-1", "song-2", "song-3"))
+			}
+		})
+
+		It("returns nil when artist is not found", func() {
+			// --- Test-specific setup ---
+			// Use prefixed ID for GetEntityByID
+			artistRepo.On("Get", "artist-unknown-artist").Return(nil, model.ErrNotFound)
+			mediaFileRepo.On("Get", "artist-unknown-artist").Return(nil, model.ErrNotFound)
+
+			// Setup for getArtist fallback to GetAll
+			artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+				return opt.Max == 1 && opt.Filters != nil
+			})).Return(model.Artists{}, nil).Maybe()
+			// --- End Test-specific setup ---
+
+			// Use prefixed ID
+			songs, err := provider.SimilarSongs(ctx, "artist-unknown-artist", 5)
+
+			Expect(err).To(Equal(model.ErrNotFound))
+			Expect(songs).To(BeNil())
+		})
+
+		It("returns songs from main artist when GetSimilarArtists returns error", func() {
+			// --- Test-specific setup ---
+			artist1 := model.Artist{ID: "artist-1", Name: "Artist One"}
+			song1 := model.MediaFile{ID: "song-1", Title: "Song One", ArtistID: "artist-1"}
+
+			// Configure artist repo Get method for getArtist
+			artistRepo.On("Get", "artist-1").Return(&artist1, nil).Maybe()
+			// Configure GetAll fallback for getArtist
+			artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+				return opt.Max == 1 && opt.Filters != nil
+			})).Return(model.Artists{artist1}, nil).Maybe() // Maybe because Get should find it
+
+			// Set the error for GetSimilarArtists
+			mockAgent.On("GetSimilarArtists", mock.Anything, "artist-1", "Artist One", "", 15).
+				Return(nil, errors.New("error getting similar artists")).Once()
+
+			// Expect call to mapSimilarArtists -> artistRepo.GetAll (returns empty)
+			artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+				return opt.Max == 0 && opt.Filters != nil // Matcher for mapSimilarArtists
+			})).Return(model.Artists{}, nil).Once()
+
+			// Setup for main artist's top songs
+			mockAgent.On("GetArtistTopSongs", mock.Anything, "artist-1", "Artist One", "", mock.Anything).
+				Return([]agents.Song{
+					{Name: "Song One", MBID: "mbid-1"},
+				}, nil).Once()
+
+			// Setup mediafile repo for finding the song
+			mediaFileRepo.FindByMBID("mbid-1", song1)
+			// --- End Test-specific setup ---
+
+			songs, err := provider.SimilarSongs(ctx, "artist-1", 5)
+
+			Expect(err).ToNot(HaveOccurred())
+			Expect(songs).To(HaveLen(1))
+			Expect(songs[0].ID).To(Equal("song-1"))
+		})
+
+		It("returns empty list when GetArtistTopSongs returns error", func() {
+			// --- Test-specific setup ---
+			artist1 := model.Artist{ID: "artist-1", Name: "Artist One"}
+
+			// Configure artist repo Get method for getArtist
+			artistRepo.On("Get", "artist-1").Return(&artist1, nil).Maybe()
+			// Configure GetAll fallback for getArtist
+			artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+				return opt.Max == 1 && opt.Filters != nil
+			})).Return(model.Artists{artist1}, nil).Maybe() // Maybe because Get should find it
+
+			// Expect GetSimilarArtists call (returns empty)
+			mockAgent.On("GetSimilarArtists", mock.Anything, "artist-1", "Artist One", "", 15).
+				Return([]agents.Artist{}, nil).Once()
+
+			// Expect call to mapSimilarArtists -> artistRepo.GetAll (returns empty)
+			artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+				return opt.Max == 0 && opt.Filters != nil // Matcher for mapSimilarArtists
+			})).Return(model.Artists{}, nil).Once()
+
+			// Set error for GetArtistTopSongs (for the main artist)
+			mockAgent.On("GetArtistTopSongs", mock.Anything, "artist-1", "Artist One", "", mock.Anything).
+				Return(nil, errors.New("error getting top songs")).Once()
+			// --- End Test-specific setup ---
+
+			songs, err := provider.SimilarSongs(ctx, "artist-1", 5)
+
+			Expect(err).ToNot(HaveOccurred())
+			Expect(songs).To(BeEmpty())
+		})
+
+		It("respects count parameter", func() {
+			// --- Test-specific setup ---
+			artist1 := model.Artist{ID: "artist-1", Name: "Artist One"}
+			song1 := model.MediaFile{ID: "song-1", Title: "Song One", ArtistID: "artist-1"}
+			song2 := model.MediaFile{ID: "song-2", Title: "Song Two", ArtistID: "artist-1"}
+
+			// Configure artist repo Get method for getArtist
+			artistRepo.On("Get", "artist-1").Return(&artist1, nil).Maybe()
+			// Configure GetAll fallback for getArtist
+			artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+				return opt.Max == 1 && opt.Filters != nil
+			})).Return(model.Artists{artist1}, nil).Maybe() // Maybe because Get should find it
+
+			// Expect GetSimilarArtists call (returns empty)
+			mockAgent.On("GetSimilarArtists", mock.Anything, "artist-1", "Artist One", "", 15).
+				Return([]agents.Artist{}, nil).Once()
+
+			// Expect call to mapSimilarArtists -> artistRepo.GetAll (returns empty)
+			artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+				return opt.Max == 0 && opt.Filters != nil // Matcher for mapSimilarArtists
+			})).Return(model.Artists{}, nil).Once()
+
+			// Setup for main artist's top songs
+			mockAgent.On("GetArtistTopSongs", mock.Anything, "artist-1", "Artist One", "", mock.Anything).
+				Return([]agents.Song{
+					{Name: "Song One", MBID: "mbid-1"},
+					{Name: "Song Two", MBID: "mbid-2"},
+				}, nil).Once()
+
+			// Setup mediafile repo for finding the songs
+			mediaFileRepo.FindByMBID("mbid-1", song1)
+			mediaFileRepo.FindByMBID("mbid-2", song2)
+			// --- End Test-specific setup ---
+
+			songs, err := provider.SimilarSongs(ctx, "artist-1", 1)
+
+			Expect(err).ToNot(HaveOccurred())
+			Expect(songs).To(HaveLen(1))
+			Expect(songs[0].ID).To(BeElementOf("song-1", "song-2"))
+		})
+	})
+})
+
+// Combined implementation of both ArtistTopSongsRetriever and ArtistSimilarRetriever interfaces
+type mockSimilarArtistAgent struct {
+	mock.Mock
+	agents.Interface
+}
+
+func (m *mockSimilarArtistAgent) AgentName() string {
+	return "mock"
+}
+
+func (m *mockSimilarArtistAgent) GetArtistTopSongs(ctx context.Context, id, artistName, mbid string, count int) ([]agents.Song, error) {
+	args := m.Called(ctx, id, artistName, mbid, count)
+	if args.Get(0) != nil {
+		return args.Get(0).([]agents.Song), args.Error(1)
+	}
+	return nil, args.Error(1)
+}
+
+func (m *mockSimilarArtistAgent) GetSimilarArtists(ctx context.Context, id, name, mbid string, limit int) ([]agents.Artist, error) {
+	args := m.Called(ctx, id, name, mbid, limit)
+	if args.Get(0) != nil {
+		return args.Get(0).([]agents.Artist), args.Error(1)
+	}
+	return nil, args.Error(1)
+}
+
+// A simple implementation of the Agents interface that combines separate implementations
+type mockCombinedAgents struct {
+	topSongsAgent agents.ArtistTopSongsRetriever
+	similarAgent  agents.ArtistSimilarRetriever
+}
+
+func (m *mockCombinedAgents) AgentName() string {
+	return "mockCombined"
+}
+
+func (m *mockCombinedAgents) GetArtistMBID(ctx context.Context, id string, name string) (string, error) {
+	return "", nil
+}
+
+func (m *mockCombinedAgents) GetArtistURL(ctx context.Context, id, name, mbid string) (string, error) {
+	return "", nil
+}
+
+func (m *mockCombinedAgents) GetArtistBiography(ctx context.Context, id, name, mbid string) (string, error) {
+	return "", nil
+}
+
+func (m *mockCombinedAgents) GetSimilarArtists(ctx context.Context, id, name, mbid string, limit int) ([]agents.Artist, error) {
+	if m.similarAgent != nil {
+		return m.similarAgent.GetSimilarArtists(ctx, id, name, mbid, limit)
+	}
+	return nil, agents.ErrNotFound
+}
+
+func (m *mockCombinedAgents) GetArtistImages(ctx context.Context, id, name, mbid string) ([]agents.ExternalImage, error) {
+	return nil, agents.ErrNotFound
+}
+
+func (m *mockCombinedAgents) GetArtistTopSongs(ctx context.Context, id, artistName, mbid string, count int) ([]agents.Song, error) {
+	if m.topSongsAgent != nil {
+		return m.topSongsAgent.GetArtistTopSongs(ctx, id, artistName, mbid, count)
+	}
+	return nil, agents.ErrNotFound
+}
+
+func (m *mockCombinedAgents) GetAlbumInfo(ctx context.Context, name, artist, mbid string) (*agents.AlbumInfo, error) {
+	return nil, agents.ErrNotFound
+}
+
+// Mocked ArtistRepo for similar songs tests
+type mockSimArtistRepo struct {
+	mock.Mock
+	model.ArtistRepository
+}
+
+func newMockSimArtistRepo() *mockSimArtistRepo {
+	return &mockSimArtistRepo{}
+}
+
+func (m *mockSimArtistRepo) SetData(artists model.Artists) {
+	// Store the data for Get queries
+	for _, a := range artists {
+		// Capture the loop variable by value
+		artistCopy := a
+		// Revert: Get does not take context
+		m.On("Get", artistCopy.ID).Return(&artistCopy, nil)
+	}
+}
+
+// Revert: Get does not take context
+func (m *mockSimArtistRepo) Get(id string) (*model.Artist, error) {
+	// Revert: Remove context from Called
+	args := m.Called(id)
+	if args.Get(0) == nil {
+		return nil, args.Error(1)
+	}
+	return args.Get(0).(*model.Artist), args.Error(1)
+}
+
+func (m *mockSimArtistRepo) SetError(hasError bool) {
+	if hasError {
+		// Revert: Remove context from GetAll mock setup
+		m.On("GetAll", mock.Anything).Return(nil, errors.New("error"))
+	}
+}
+
+func (m *mockSimArtistRepo) FindByName(name string, artist model.Artist) {
+	// Set up a mock for finding an artist by name with LIKE filter, using Anything matcher for flexibility
+	// Revert: Remove context from GetAll mock setup
+	m.On("GetAll", mock.Anything).Return(model.Artists{artist}, nil).Once()
+}
+
+// Revert: Remove context from GetAll signature
+func (m *mockSimArtistRepo) GetAll(options ...model.QueryOptions) (model.Artists, error) {
+	// Pass options correctly to Called
+	// Convert options slice to []interface{} for Called
+	argsSlice := make([]interface{}, len(options))
+	for i, v := range options {
+		argsSlice[i] = v
+	}
+	args := m.Called(argsSlice...)
+	if args.Get(0) == nil {
+		return nil, args.Error(1)
+	}
+	return args.Get(0).(model.Artists), args.Error(1)
+}
+
+// Mocked MediaFileRepo for similar songs tests
+type mockSimMediaFileRepo struct {
+	mock.Mock
+	model.MediaFileRepository
+}
+
+func newMockSimMediaFileRepo() *mockSimMediaFileRepo {
+	return &mockSimMediaFileRepo{}
+}
+
+func (m *mockSimMediaFileRepo) SetData(mediaFiles model.MediaFiles) {
+	// Store the data for Get queries
+	for _, mf := range mediaFiles {
+		mfCopy := mf // Capture loop variable
+		// Revert: Get does not take context
+		m.On("Get", mfCopy.ID).Return(&mfCopy, nil)
+	}
+}
+
+// Revert: Get does not take context
+func (m *mockSimMediaFileRepo) Get(id string) (*model.MediaFile, error) {
+	// Revert: Remove context from Called
+	args := m.Called(id)
+	if args.Get(0) == nil {
+		return nil, args.Error(1)
+	}
+	return args.Get(0).(*model.MediaFile), args.Error(1)
+}
+
+func (m *mockSimMediaFileRepo) SetError(hasError bool) {
+	if hasError {
+		// Revert: Remove context from GetAll mock setup
+		m.On("GetAll", mock.Anything).Return(nil, errors.New("error"))
+	}
+}
+
+func (m *mockSimMediaFileRepo) FindByMBID(mbid string, mediaFile model.MediaFile) {
+	// Set up a mock for finding a media file by MBID using Anything matcher for flexibility
+	// Revert: Remove context from GetAll mock setup
+	m.On("GetAll", mock.Anything).Return(model.MediaFiles{mediaFile}, nil).Once()
+}
+
+func (m *mockSimMediaFileRepo) FindByArtistAndTitle(artistID string, title string, mediaFile model.MediaFile) {
+	// Set up a mock for finding a media file by artist ID and title
+	// Revert: Remove context from GetAll mock setup
+	m.On("GetAll", mock.Anything).Return(model.MediaFiles{mediaFile}, nil).Once()
+}
+
+// Revert: Remove context from GetAll signature
+func (m *mockSimMediaFileRepo) GetAll(options ...model.QueryOptions) (model.MediaFiles, error) {
+	// Pass options correctly to Called
+	// Convert options slice to []interface{} for Called
+	argsSlice := make([]interface{}, len(options))
+	for i, v := range options {
+		argsSlice[i] = v
+	}
+	args := m.Called(argsSlice...)
+	if args.Get(0) == nil {
+		return nil, args.Error(1)
+	}
+	return args.Get(0).(model.MediaFiles), args.Error(1)
+}