Merge pull request 'Taste-profile fidelity (M160) + Songs-like row + home polish' (#109) from dev into main

Milestone #160 Opt 3b. Adds device class as a third context axis on top
of the #1531 time-of-day/weekday affinity: on the radio path, a candidate
is boosted when its artist concentrates in the current (daypart × weekday
× device) cell. Client-sent (client_id is opaque; no UA stored), so it's
captured going forward and applies to radio only (daily mixes are
cron-built with no device → stay device-agnostic).

Server:
- Migration 0048: play_events.device_class text NULL (no CHECK; normalized
  in Go — one whitelist entry per new client class, not a migration).
- events.go: eventRequest.device_class + normalizeDeviceClass (whitelist →
  mobile/web/…, else "other", empty → NULL); threaded through both
  RecordPlayStartedWithSource and RecordOfflinePlay into InsertPlayEvent.
- ListArtistContextPlayCountsForUser gains a current-device param; the cell
  FILTER adds AND ($2='' OR device_class=$2) — '' reproduces the #1531
  time-only behaviour exactly (used by mixes). SessionVector.DeviceClass
  carries it; the radio handler derives the current device from the user's
  latest play (GetLatestPlayDeviceClassForUser) — request-free proxy.
- No new tuning knob: device narrows the existing ContextAffinityScore
  (reuses context_time_weight).

Clients:
- web: play_started sends device_class 'web'.
- android: play_started + offline replay send 'mobile' (EventsWire +
  PlayOfflinePayload + MutationReplayer + PlayEventsReporter).

Test: LoadContextAffinity device-narrowing integration test (mobile vs web
artist separation; device-agnostic parity).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

android/app/src/main/java/com/fabledsword/minstrel/admin/data/AdminTagSourcesRepository.kt

@@ -0,0 +1,48 @@
+package com.fabledsword.minstrel.admin.data
+
+import com.fabledsword.minstrel.api.endpoints.AdminTagSourcesApi
+import com.fabledsword.minstrel.api.endpoints.UpdateTagSourceBody
+import com.fabledsword.minstrel.models.AdminTagSourceRef
+import com.fabledsword.minstrel.models.TagSourceTestResult
+import com.fabledsword.minstrel.models.wire.AdminTagSourceWire
+import com.fabledsword.minstrel.models.wire.TestTagSourceWire
+import retrofit2.Retrofit
+import retrofit2.create
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Read-through accessor for the tag-enrichment provider settings (#1521).
+ * No Room caching — admin settings are infrequent point-and-shoot edits;
+ * mutations fire direct REST and the ViewModel reconciles on failure.
+ * Exceptions propagate to the ViewModel (which maps them via ErrorCopy).
+ */
+@Singleton
+class AdminTagSourcesRepository @Inject constructor(
+    retrofit: Retrofit,
+) {
+    private val api: AdminTagSourcesApi = retrofit.create()
+
+    suspend fun list(): List<AdminTagSourceRef> = api.list().providers.map { it.toDomain() }
+
+    suspend fun setEnabled(id: String, enabled: Boolean): AdminTagSourceRef =
+        api.update(id, UpdateTagSourceBody(enabled = enabled)).toDomain()
+
+    suspend fun setApiKey(id: String, apiKey: String): AdminTagSourceRef =
+        api.update(id, UpdateTagSourceBody(apiKey = apiKey)).toDomain()
+
+    suspend fun test(id: String): TagSourceTestResult = api.test(id).toResult()
+}
+
+private fun AdminTagSourceWire.toDomain(): AdminTagSourceRef = AdminTagSourceRef(
+    id = id,
+    displayName = displayName,
+    requiresApiKey = requiresApiKey,
+    supports = supports,
+    enabled = enabled,
+    apiKeySet = apiKeySet,
+    testable = testable,
+)
+
+private fun TestTagSourceWire.toResult(): TagSourceTestResult =
+    TagSourceTestResult(ok = ok, durationMs = durationMs, error = error)

android/app/src/main/java/com/fabledsword/minstrel/admin/ui/AdminLandingScreen.kt

@@ -28,15 +28,18 @@ import androidx.lifecycle.viewModelScope
 import androidx.navigation.NavHostController
 import com.composables.icons.lucide.Inbox
 import com.composables.icons.lucide.Lucide
+import com.composables.icons.lucide.Music
 import com.composables.icons.lucide.TriangleAlert
 import com.composables.icons.lucide.Users
 import com.fabledsword.minstrel.admin.data.AdminQuarantineRepository
 import com.fabledsword.minstrel.admin.data.AdminRequestsRepository
+import com.fabledsword.minstrel.admin.data.AdminTagSourcesRepository
 import com.fabledsword.minstrel.admin.data.AdminUsersRepository
 import com.fabledsword.minstrel.api.ErrorCopy
 import com.fabledsword.minstrel.nav.Admin
 import com.fabledsword.minstrel.nav.AdminQuarantine
 import com.fabledsword.minstrel.nav.AdminRequests
+import com.fabledsword.minstrel.nav.AdminTagSources
 import com.fabledsword.minstrel.nav.AdminUsers
 import com.fabledsword.minstrel.shared.widgets.EmptyState
 import com.fabledsword.minstrel.shared.widgets.LoadingCentered
@@ -54,7 +57,7 @@ import javax.inject.Inject
 
 // ─── State ───────────────────────────────────────────────────────────
 
-data class AdminCounts(val requests: Int, val quarantine: Int, val users: Int)
+data class AdminCounts(val requests: Int, val quarantine: Int, val users: Int, val tagSources: Int)
 
 sealed interface AdminLandingUiState {
     data object Loading : AdminLandingUiState
@@ -69,6 +72,7 @@ class AdminLandingViewModel @Inject constructor(
     private val requestsRepo: AdminRequestsRepository,
     private val quarantineRepo: AdminQuarantineRepository,
     private val usersRepo: AdminUsersRepository,
+    private val tagSourcesRepo: AdminTagSourcesRepository,
 ) : ViewModel() {
 
     private val internal = MutableStateFlow<AdminLandingUiState>(AdminLandingUiState.Loading)
@@ -85,7 +89,8 @@ class AdminLandingViewModel @Inject constructor(
                 val req = async { requestsRepo.list().size }
                 val qua = async { quarantineRepo.list().size }
                 val usr = async { usersRepo.list().size }
-                AdminCounts(req.await(), qua.await(), usr.await())
+                val tag = async { tagSourcesRepo.list().count { it.enabled } }
+                AdminCounts(req.await(), qua.await(), usr.await(), tag.await())
             }
             internal.value = AdminLandingUiState.Success(counts)
         } catch (
@@ -170,6 +175,15 @@ private fun SectionList(counts: AdminCounts, navController: NavHostController) {
                 onClick = { navController.navigate(AdminUsers) },
             )
         }
+        item {
+            SectionCard(
+                icon = Lucide.Music,
+                title = "Tag sources",
+                subtitle = "Metadata enrichment providers",
+                count = counts.tagSources,
+                onClick = { navController.navigate(AdminTagSources) },
+            )
+        }
     }
 }
 

android/app/src/main/java/com/fabledsword/minstrel/admin/ui/AdminTagSourcesScreen.kt

@@ -0,0 +1,220 @@
+package com.fabledsword.minstrel.admin.ui
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material3.Button
+import androidx.compose.material3.ElevatedCard
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Switch
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.text.input.PasswordVisualTransformation
+import androidx.compose.ui.unit.dp
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import androidx.navigation.NavHostController
+import com.fabledsword.minstrel.models.AdminTagSourceRef
+import com.fabledsword.minstrel.models.TagSourceTestResult
+import com.fabledsword.minstrel.nav.AdminTagSources
+import com.fabledsword.minstrel.shared.widgets.EmptyState
+import com.fabledsword.minstrel.shared.widgets.ErrorRetry
+import com.fabledsword.minstrel.shared.widgets.LoadingCentered
+import com.fabledsword.minstrel.shared.widgets.MinstrelTopAppBar
+import com.fabledsword.minstrel.shared.widgets.PullToRefreshScaffold
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun AdminTagSourcesScreen(
+    navController: NavHostController,
+    viewModel: AdminTagSourcesViewModel = hiltViewModel(),
+) {
+    val state by viewModel.uiState.collectAsStateWithLifecycle()
+    Scaffold(
+        modifier = Modifier.fillMaxSize(),
+        topBar = {
+            MinstrelTopAppBar(
+                title = "Admin · Tag sources",
+                navController = navController,
+                currentRouteName = AdminTagSources::class.qualifiedName,
+                onBack = { navController.popBackStack() },
+            )
+        },
+    ) { inner ->
+        PullToRefreshScaffold(
+            onRefresh = { viewModel.refresh().join() },
+            modifier = Modifier.fillMaxSize().padding(inner),
+        ) {
+            when (val s = state) {
+                AdminTagSourcesUiState.Loading -> LoadingCentered()
+                AdminTagSourcesUiState.Empty -> EmptyState(
+                    title = "No tag sources",
+                    body = "Tag-enrichment providers register on the server; none are available.",
+                )
+                is AdminTagSourcesUiState.Error -> ErrorRetry(
+                    title = "Couldn't load tag sources",
+                    message = s.message,
+                    onRetry = { viewModel.refresh() },
+                )
+                is AdminTagSourcesUiState.Success -> TagSourceList(
+                    providers = s.providers,
+                    testResults = s.testResults,
+                    onToggle = viewModel::setEnabled,
+                    onSaveKey = viewModel::saveApiKey,
+                    onTest = viewModel::test,
+                )
+            }
+        }
+    }
+}
+
+@Composable
+private fun TagSourceList(
+    providers: List<AdminTagSourceRef>,
+    testResults: Map<String, TagSourceTestResult>,
+    onToggle: (String, Boolean) -> Unit,
+    onSaveKey: (String, String) -> Unit,
+    onTest: (String) -> Unit,
+) {
+    LazyColumn(
+        modifier = Modifier.fillMaxSize(),
+        contentPadding = PaddingValues(16.dp),
+        verticalArrangement = Arrangement.spacedBy(12.dp),
+    ) {
+        items(items = providers, key = { it.id }) { provider ->
+            TagSourceCard(
+                provider = provider,
+                testResult = testResults[provider.id],
+                onToggle = onToggle,
+                onSaveKey = onSaveKey,
+                onTest = onTest,
+            )
+        }
+    }
+}
+
+@Composable
+private fun TagSourceCard(
+    provider: AdminTagSourceRef,
+    testResult: TagSourceTestResult?,
+    onToggle: (String, Boolean) -> Unit,
+    onSaveKey: (String, String) -> Unit,
+    onTest: (String) -> Unit,
+) {
+    ElevatedCard(modifier = Modifier.fillMaxWidth()) {
+        Column(
+            modifier = Modifier.fillMaxWidth().padding(16.dp),
+            verticalArrangement = Arrangement.spacedBy(10.dp),
+        ) {
+            Row(
+                modifier = Modifier.fillMaxWidth(),
+                verticalAlignment = Alignment.CenterVertically,
+                horizontalArrangement = Arrangement.SpaceBetween,
+            ) {
+                Column(modifier = Modifier.weight(1f)) {
+                    Text(provider.displayName, style = MaterialTheme.typography.titleMedium)
+                    Text(
+                        text = provider.supports.joinToString(", ") { it.replace('_', ' ') },
+                        style = MaterialTheme.typography.bodySmall,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    )
+                }
+                Switch(
+                    checked = provider.enabled,
+                    onCheckedChange = { onToggle(provider.id, it) },
+                )
+            }
+            if (provider.requiresApiKey) {
+                ApiKeyRow(provider = provider, onSaveKey = onSaveKey)
+            }
+            if (provider.testable) {
+                TestRow(provider = provider, testResult = testResult, onTest = onTest)
+            }
+        }
+    }
+}
+
+@Composable
+private fun ApiKeyRow(provider: AdminTagSourceRef, onSaveKey: (String, String) -> Unit) {
+    var key by remember(provider.id) { mutableStateOf("") }
+    OutlinedTextField(
+        value = key,
+        onValueChange = { key = it },
+        modifier = Modifier.fillMaxWidth(),
+        label = { Text("API key") },
+        placeholder = {
+            Text(
+                if (provider.apiKeySet) {
+                    "••• saved — leave blank to keep"
+                } else {
+                    "Paste your API key to enable this source"
+                },
+            )
+        },
+        singleLine = true,
+        visualTransformation = PasswordVisualTransformation(),
+        keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Password),
+    )
+    Row(
+        horizontalArrangement = Arrangement.spacedBy(8.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Button(
+            onClick = {
+                onSaveKey(provider.id, key)
+                key = ""
+            },
+            enabled = key.isNotBlank(),
+        ) { Text("Save key") }
+        if (provider.apiKeySet) {
+            Text("✓ Set", style = MaterialTheme.typography.bodySmall)
+        }
+    }
+}
+
+@Composable
+private fun TestRow(
+    provider: AdminTagSourceRef,
+    testResult: TagSourceTestResult?,
+    onTest: (String) -> Unit,
+) {
+    Row(
+        horizontalArrangement = Arrangement.spacedBy(8.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        OutlinedButton(onClick = { onTest(provider.id) }) { Text("Test connection") }
+        testResult?.let { result ->
+            if (result.ok) {
+                Text(
+                    text = "OK (${result.durationMs}ms)",
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.primary,
+                )
+            } else {
+                Text(
+                    text = "Failed — ${result.error}",
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.error,
+                )
+            }
+        }
+    }
+}

android/app/src/main/java/com/fabledsword/minstrel/admin/ui/AdminTagSourcesViewModel.kt

@@ -0,0 +1,116 @@
+package com.fabledsword.minstrel.admin.ui
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import com.fabledsword.minstrel.admin.data.AdminTagSourcesRepository
+import com.fabledsword.minstrel.api.ErrorCopy
+import com.fabledsword.minstrel.connectivity.NetworkStatusController
+import com.fabledsword.minstrel.connectivity.recoveries
+import com.fabledsword.minstrel.models.AdminTagSourceRef
+import com.fabledsword.minstrel.models.TagSourceTestResult
+import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.launch
+import javax.inject.Inject
+
+sealed interface AdminTagSourcesUiState {
+    data object Loading : AdminTagSourcesUiState
+    data object Empty : AdminTagSourcesUiState
+    data class Success(
+        val providers: List<AdminTagSourceRef>,
+        val testResults: Map<String, TagSourceTestResult>,
+    ) : AdminTagSourcesUiState
+    data class Error(val message: String) : AdminTagSourcesUiState
+}
+
+@HiltViewModel
+class AdminTagSourcesViewModel @Inject constructor(
+    private val repository: AdminTagSourcesRepository,
+    networkStatus: NetworkStatusController,
+) : ViewModel() {
+
+    private val internal = MutableStateFlow<AdminTagSourcesUiState>(AdminTagSourcesUiState.Loading)
+    val uiState: StateFlow<AdminTagSourcesUiState> = internal.asStateFlow()
+
+    init {
+        refresh()
+        // Screen-level auto-recovery: reload a failed list when server
+        // health returns instead of waiting for a manual pull (issue #1245).
+        viewModelScope.launch {
+            networkStatus.recoveries().collect {
+                if (internal.value is AdminTagSourcesUiState.Error) refresh()
+            }
+        }
+    }
+
+    fun refresh(): Job = viewModelScope.launch {
+        internal.value = AdminTagSourcesUiState.Loading
+        try {
+            val providers = repository.list()
+            internal.value = if (providers.isEmpty()) {
+                AdminTagSourcesUiState.Empty
+            } else {
+                AdminTagSourcesUiState.Success(providers, emptyMap())
+            }
+        } catch (
+            @Suppress("TooGenericExceptionCaught") e: Throwable,
+        ) {
+            internal.value = AdminTagSourcesUiState.Error(ErrorCopy.fromThrowable(e))
+        }
+    }
+
+    fun setEnabled(id: String, enabled: Boolean) {
+        val before = internal.value as? AdminTagSourcesUiState.Success ?: return
+        // Optimistic toggle; reconcile via refresh() if the server rejects.
+        internal.value = before.copy(
+            providers = before.providers.map {
+                if (it.id == id) it.copy(enabled = enabled) else it
+            },
+        )
+        viewModelScope.launch {
+            try {
+                repository.setEnabled(id, enabled)
+            } catch (
+                @Suppress("TooGenericExceptionCaught", "SwallowedException") e: Throwable,
+            ) {
+                refresh()
+            }
+        }
+    }
+
+    fun saveApiKey(id: String, apiKey: String) {
+        viewModelScope.launch {
+            try {
+                replaceProvider(repository.setApiKey(id, apiKey))
+            } catch (
+                @Suppress("TooGenericExceptionCaught", "SwallowedException") e: Throwable,
+            ) {
+                refresh()
+            }
+        }
+    }
+
+    fun test(id: String) {
+        viewModelScope.launch {
+            val result = try {
+                repository.test(id)
+            } catch (
+                @Suppress("TooGenericExceptionCaught") e: Throwable,
+            ) {
+                TagSourceTestResult(ok = false, error = ErrorCopy.fromThrowable(e))
+            }
+            val current = internal.value as? AdminTagSourcesUiState.Success ?: return@launch
+            internal.value = current.copy(testResults = current.testResults + (id to result))
+        }
+    }
+
+    private fun replaceProvider(updated: AdminTagSourceRef) {
+        val current = internal.value as? AdminTagSourcesUiState.Success ?: return
+        internal.value = current.copy(
+            providers = current.providers.map { if (it.id == updated.id) updated else it },
+        )
+    }
+}

android/app/src/main/java/com/fabledsword/minstrel/api/endpoints/AdminTagSourcesApi.kt

@@ -0,0 +1,41 @@
+package com.fabledsword.minstrel.api.endpoints
+
+import com.fabledsword.minstrel.models.wire.AdminTagSourceWire
+import com.fabledsword.minstrel.models.wire.AdminTagSourcesListWire
+import com.fabledsword.minstrel.models.wire.TestTagSourceWire
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+import retrofit2.http.Body
+import retrofit2.http.GET
+import retrofit2.http.PATCH
+import retrofit2.http.POST
+import retrofit2.http.Path
+
+/**
+ * Retrofit interface for `/api/admin/tag-sources` (#1521) — the admin
+ * surface for the tag-enrichment provider settings (#1490). Mirrors the
+ * web integrations "Tag enrichment sources" card. Same shape as the
+ * cover-sources admin surface; kept independent so a new tag source is
+ * added without touching art settings.
+ */
+interface AdminTagSourcesApi {
+    @GET("api/admin/tag-sources")
+    suspend fun list(): AdminTagSourcesListWire
+
+    @PATCH("api/admin/tag-sources/{id}")
+    suspend fun update(@Path("id") id: String, @Body body: UpdateTagSourceBody): AdminTagSourceWire
+
+    @POST("api/admin/tag-sources/{id}/test")
+    suspend fun test(@Path("id") id: String): TestTagSourceWire
+}
+
+/**
+ * PATCH body. Both fields are nullable + default-null so kotlinx omits the
+ * untouched one (the server reads a missing/null field as "leave
+ * unchanged"): send only `enabled` to toggle, only `apiKey` to set a key.
+ */
+@Serializable
+data class UpdateTagSourceBody(
+    val enabled: Boolean? = null,
+    @SerialName("api_key") val apiKey: String? = null,
+)

android/app/src/main/java/com/fabledsword/minstrel/cache/mutations/MutationQueue.kt

@@ -239,6 +239,9 @@ data class PlayOfflinePayload(
     val atIso: String,
     val durationPlayedMs: Long,
     val source: String? = null,
+    // #1551: device class for context conditioning; null on payloads queued
+    // before this field existed (decodes to null → server stores NULL).
+    val deviceClass: String? = null,
 )
 
 /**

android/app/src/main/java/com/fabledsword/minstrel/cache/mutations/MutationReplayer.kt

@@ -254,6 +254,7 @@ class MutationReplayer @Inject constructor(
                 at = decoded.atIso,
                 durationPlayedMs = decoded.durationPlayedMs,
                 source = decoded.source,
+                deviceClass = decoded.deviceClass,
             ),
         )
         return Outcome.SENT

android/app/src/main/java/com/fabledsword/minstrel/models/AdminTagSourceRef.kt

@@ -0,0 +1,19 @@
+package com.fabledsword.minstrel.models
+
+/** Domain model for one tag-enrichment provider in the admin surface (#1521). */
+data class AdminTagSourceRef(
+    val id: String,
+    val displayName: String,
+    val requiresApiKey: Boolean,
+    val supports: List<String>,
+    val enabled: Boolean,
+    val apiKeySet: Boolean,
+    val testable: Boolean,
+)
+
+/** Result of a provider "test connection" call. */
+data class TagSourceTestResult(
+    val ok: Boolean,
+    val durationMs: Long = 0,
+    val error: String = "",
+)

android/app/src/main/java/com/fabledsword/minstrel/models/wire/AdminTagSourceWire.kt

@@ -0,0 +1,35 @@
+package com.fabledsword.minstrel.models.wire
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+/**
+ * Wire DTOs for the `/api/admin/tag-sources` admin surface (#1521).
+ * Every field defaults defensively so a missing JSON key never crashes
+ * deserialization. `versionBumped` is present only on the PATCH response.
+ */
+@Serializable
+data class AdminTagSourceWire(
+    val id: String = "",
+    @SerialName("display_name") val displayName: String = "",
+    @SerialName("requires_api_key") val requiresApiKey: Boolean = false,
+    val supports: List<String> = emptyList(),
+    val enabled: Boolean = false,
+    @SerialName("api_key_set") val apiKeySet: Boolean = false,
+    @SerialName("display_order") val displayOrder: Int = 0,
+    val testable: Boolean = false,
+    @SerialName("version_bumped") val versionBumped: Boolean = false,
+)
+
+@Serializable
+data class AdminTagSourcesListWire(
+    val providers: List<AdminTagSourceWire> = emptyList(),
+    @SerialName("sources_version") val sourcesVersion: Int = 0,
+)
+
+@Serializable
+data class TestTagSourceWire(
+    val ok: Boolean = false,
+    @SerialName("duration_ms") val durationMs: Long = 0,
+    val error: String = "",
+)

android/app/src/main/java/com/fabledsword/minstrel/models/wire/EventsWire.kt

@@ -27,6 +27,8 @@ data class PlayStartedRequest(
     @SerialName("track_id") val trackId: String,
     @SerialName("client_id") val clientId: String,
     val source: String? = null,
+    // #1551: device class for context conditioning (server normalizes).
+    @SerialName("device_class") val deviceClass: String? = null,
 )
 
 @Serializable
@@ -56,4 +58,6 @@ data class PlayOfflineRequest(
     val at: String,
     @SerialName("duration_played_ms") val durationPlayedMs: Long,
     val source: String? = null,
+    // #1551: device class for context conditioning (server normalizes).
+    @SerialName("device_class") val deviceClass: String? = null,
 )

android/app/src/main/java/com/fabledsword/minstrel/nav/MinstrelNavGraph.kt

@@ -16,6 +16,7 @@ import androidx.navigation.compose.composable
 import com.fabledsword.minstrel.admin.ui.AdminLandingScreen
 import com.fabledsword.minstrel.admin.ui.AdminQuarantineScreen
 import com.fabledsword.minstrel.admin.ui.AdminRequestsScreen
+import com.fabledsword.minstrel.admin.ui.AdminTagSourcesScreen
 import com.fabledsword.minstrel.admin.ui.AdminUsersScreen
 import com.fabledsword.minstrel.auth.ui.LoginScreen
 import com.fabledsword.minstrel.auth.ui.ServerUrlScreen
@@ -190,6 +191,13 @@ private fun NavGraphBuilder.inShellDetail(
             }
         }
     }
+    composable<AdminTagSources> {
+        WithAnimatedScope {
+            ShellScaffold(onExpandPlayer = expandPlayer) {
+                AdminTagSourcesScreen(navController = navController)
+            }
+        }
+    }
 }
 
 private fun NavGraphBuilder.outsideShell(navController: NavHostController) {

android/app/src/main/java/com/fabledsword/minstrel/nav/Routes.kt

@@ -22,6 +22,7 @@ import kotlinx.serialization.Serializable
 @Serializable data object AdminRequests
 @Serializable data object AdminQuarantine
 @Serializable data object AdminUsers
+@Serializable data object AdminTagSources
 
 // ── Outside-shell full-screen routes ──────────────────────────────────
 

android/app/src/main/java/com/fabledsword/minstrel/player/PlayEventsReporter.kt

@@ -155,6 +155,7 @@ class PlayEventsReporter @Inject constructor(
                         trackId = trackId,
                         clientId = cid,
                         source = source.takeIf { !it.isNullOrEmpty() },
+                        deviceClass = DEVICE_CLASS,
                     ),
                 )
                 if (curTrackId == trackId) {
@@ -248,6 +249,7 @@ class PlayEventsReporter @Inject constructor(
                     atIso = startedAt.toString(),
                     durationPlayedMs = durationPlayedMs,
                     source = source.takeIf { !it.isNullOrEmpty() },
+                    deviceClass = DEVICE_CLASS,
                 ),
             )
         }
@@ -268,6 +270,12 @@ class PlayEventsReporter @Inject constructor(
 
     // ── Lifecycle: durable-close on app background / detach ────────
 
+    companion object {
+        // #1551: Android is a mobile client. Refine to tablet/tv via device
+        // configuration later if the metrics trend view shows it matters.
+        private const val DEVICE_CLASS = "mobile"
+    }
+
     override fun onStop(owner: LifecycleOwner) {
         // App backgrounded. If the tracked play is still PLAYING, leave it
         // alone: the foreground media service keeps the process — and this

cmd/minstrel/main.go

@@ -15,6 +15,7 @@ import (
 	"github.com/jackc/pgx/v5/pgxpool"
 
 	"git.fabledsword.com/bvandeusen/minstrel/internal/config"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/coplay"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/coverart"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/db"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/eventbus"
@@ -206,6 +207,12 @@ func run() error {
 	similarityWorker := similarity.NewWorker(pool, listenbrainz.NewClient(), logger.With("component", "similarity"))
 	go similarityWorker.Run(ctx)
 
+	// Start the household co-play worker (#1533). Recomputes artist–artist
+	// co-occurrence edges (source='user_cooccurrence') from play_events every
+	// 6h — a collaborative candidate arm for the radio/mix pools. Pure local
+	// SQL, no external calls; empty on single-user servers.
+	go coplay.NewWorker(pool, logger.With("component", "coplay")).Run(ctx)
+
 	// Start the tag-enrichment worker (#1490). Reconciles the compiled-in
 	// tag providers with tag_provider_settings, bumps the sources version if
 	// the provider set changed (re-opening settled rows), then drains tracks

internal/api/admin_recommendation_tuning.go

@@ -20,26 +20,28 @@ import (
 // weightsResp is one weight profile on the wire, keyed by the same
 // snake_case field names the PATCH body accepts.
 type weightsResp struct {
-	BaseWeight       float64 `json:"base_weight"`
-	LikeBoost        float64 `json:"like_boost"`
-	RecencyWeight    float64 `json:"recency_weight"`
-	SkipPenalty      float64 `json:"skip_penalty"`
-	JitterMagnitude  float64 `json:"jitter_magnitude"`
-	ContextWeight    float64 `json:"context_weight"`
-	SimilarityWeight float64 `json:"similarity_weight"`
-	TasteWeight      float64 `json:"taste_weight"`
+	BaseWeight        float64 `json:"base_weight"`
+	LikeBoost         float64 `json:"like_boost"`
+	RecencyWeight     float64 `json:"recency_weight"`
+	SkipPenalty       float64 `json:"skip_penalty"`
+	JitterMagnitude   float64 `json:"jitter_magnitude"`
+	ContextWeight     float64 `json:"context_weight"`
+	SimilarityWeight  float64 `json:"similarity_weight"`
+	TasteWeight       float64 `json:"taste_weight"`
+	ContextTimeWeight float64 `json:"context_time_weight"`
 }
 
 func weightsRespFrom(w recommendation.ScoringWeights) weightsResp {
 	return weightsResp{
-		BaseWeight:       w.BaseWeight,
-		LikeBoost:        w.LikeBoost,
-		RecencyWeight:    w.RecencyWeight,
-		SkipPenalty:      w.SkipPenalty,
-		JitterMagnitude:  w.JitterMagnitude,
-		ContextWeight:    w.ContextWeight,
-		SimilarityWeight: w.SimilarityWeight,
-		TasteWeight:      w.TasteWeight,
+		BaseWeight:        w.BaseWeight,
+		LikeBoost:         w.LikeBoost,
+		RecencyWeight:     w.RecencyWeight,
+		SkipPenalty:       w.SkipPenalty,
+		JitterMagnitude:   w.JitterMagnitude,
+		ContextWeight:     w.ContextWeight,
+		SimilarityWeight:  w.SimilarityWeight,
+		TasteWeight:       w.TasteWeight,
+		ContextTimeWeight: w.ContextTimeWeight,
 	}
 }
 
@@ -48,6 +50,9 @@ type tasteTuningResp struct {
 	EngagementHardSkip float64 `json:"engagement_hard_skip"`
 	EngagementNeutral  float64 `json:"engagement_neutral"`
 	EngagementFull     float64 `json:"engagement_full"`
+	EnrichedTagScale   float64 `json:"enriched_tag_scale"`
+	EraScale           float64 `json:"era_scale"`
+	MoodScale          float64 `json:"mood_scale"`
 }
 
 func tasteRespFrom(t recsettings.TasteTuning) tasteTuningResp {
@@ -56,6 +61,9 @@ func tasteRespFrom(t recsettings.TasteTuning) tasteTuningResp {
 		EngagementHardSkip: t.EngagementHardSkip,
 		EngagementNeutral:  t.EngagementNeutral,
 		EngagementFull:     t.EngagementFull,
+		EnrichedTagScale:   t.EnrichedTagScale,
+		EraScale:           t.EraScale,
+		MoodScale:          t.MoodScale,
 	}
 }
 

internal/api/events.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"net/http"
+	"strings"
 	"time"
 
 	"github.com/jackc/pgx/v5"
@@ -24,6 +25,33 @@ type eventRequest struct {
 	// / "discover" feed the system-playlist rotation dedup (#415);
 	// absent / "" for library, user-playlist, radio, Subsonic.
 	Source *string `json:"source"`
+	// DeviceClass is the client's self-reported device class (#1551),
+	// normalized + stored per play to condition radio on the current device.
+	DeviceClass *string `json:"device_class"`
+}
+
+// knownDeviceClasses whitelists the device classes the context-affinity facet
+// buckets by (#1551). A client sends one; anything unrecognized normalizes to
+// "other", and empty/absent to "" (stored NULL → excluded from the device
+// dimension). Kept permissive (no DB CHECK) so a new client class is one
+// whitelist entry, not a migration.
+var knownDeviceClasses = map[string]bool{
+	"mobile": true, "tablet": true, "desktop": true,
+	"web": true, "tv": true, "watch": true,
+}
+
+func normalizeDeviceClass(dc *string) string {
+	if dc == nil {
+		return ""
+	}
+	s := strings.ToLower(strings.TrimSpace(*dc))
+	if s == "" {
+		return ""
+	}
+	if knownDeviceClasses[s] {
+		return s
+	}
+	return "other"
 }
 
 type playStartedResponse struct {
@@ -114,7 +142,9 @@ func (h *handlers) handleEventPlayStarted(
 	if req.Source != nil {
 		source = *req.Source
 	}
-	res, err := h.events.RecordPlayStartedWithSource(r.Context(), user.ID, trackID, clientID, source, at)
+	deviceClass := normalizeDeviceClass(req.DeviceClass)
+	res, err := h.events.RecordPlayStartedWithSource(
+		r.Context(), user.ID, trackID, clientID, source, deviceClass, at)
 	if err != nil {
 		h.logger.Error("api: events: play_started", "err", err)
 		writeErr(w, apierror.InternalMsg("record failed", err))
@@ -159,7 +189,8 @@ func (h *handlers) handleEventPlayOffline(
 		source = *req.Source
 	}
 	if err := h.events.RecordOfflinePlay(
-		r.Context(), user.ID, trackID, clientID, source, at, *req.DurationPlayedMs,
+		r.Context(), user.ID, trackID, clientID, source,
+		normalizeDeviceClass(req.DeviceClass), at, *req.DurationPlayedMs,
 	); err != nil {
 		h.logger.Error("api: events: play_offline", "err", err)
 		writeErr(w, apierror.InternalMsg("record failed", err))

internal/api/radio.go

@@ -1,6 +1,7 @@
 package api
 
 import (
+	"context"
 	"encoding/json"
 	"errors"
 	"log/slog"
@@ -81,6 +82,9 @@ func (h *handlers) handleRadio(w http.ResponseWriter, r *http.Request) {
 	}
 
 	currentVec := loadCurrentSessionVector(r, q, user.ID, h.logger)
+	// Condition on the current device (#1551): the latest play's device is a
+	// cheap, request-free proxy for what the user is on right now.
+	currentVec.DeviceClass = latestDeviceClass(r.Context(), q, user.ID, h.logger)
 
 	exclude := parseExcludeParam(r.URL.Query().Get("exclude"))
 	limits := recommendation.DefaultCandidateSourceLimits()
@@ -150,6 +154,24 @@ func loadCurrentSessionVector(r *http.Request, q *dbq.Queries, userID pgtype.UUI
 	return v
 }
 
+// latestDeviceClass returns the device_class of the user's most recent play as
+// the "current device" for context conditioning (#1551), or "" when unknown
+// (no plays yet, or the latest play predates device capture). Best-effort: a
+// lookup failure yields a device-agnostic ("") affinity cell.
+func latestDeviceClass(ctx context.Context, q *dbq.Queries, userID pgtype.UUID, logger *slog.Logger) string {
+	dc, err := q.GetLatestPlayDeviceClassForUser(ctx, userID)
+	if err != nil {
+		if !errors.Is(err, pgx.ErrNoRows) {
+			logger.Warn("api: radio: latest device class", "err", err)
+		}
+		return ""
+	}
+	if dc == nil {
+		return ""
+	}
+	return *dc
+}
+
 // parseExcludeParam parses a comma-separated list of UUIDs from the
 // `exclude` query string, silently dropping malformed entries. Returns
 // nil for empty or all-malformed input.

internal/coplay/worker.go

@@ -0,0 +1,86 @@
+// Package coplay builds household co-play similarity edges (#1533, milestone
+// #160 Opt 5). Minstrel is a single shared-library, multi-user server (no
+// per-user library ACL), so the "household" is the whole instance's user set.
+// A periodic worker recomputes artist–artist co-occurrence from play_events
+// entirely in SQL (no external API) and stores the edges in artist_similarity
+// under source='user_cooccurrence' — the pre-provisioned co-occurrence source
+// from the 0009 schema — which the radio/mix candidate pool consumes as a
+// collaborative arm. Single-user servers produce no edges (the >= 2 co-player
+// gate), so the feature is a graceful no-op there.
+package coplay
+
+import (
+	"context"
+	"log/slog"
+	"time"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
+)
+
+// minJaccard is the co-play edge floor: prune weak pairs and self-limit hub
+// artists, whose large combined-audience denominators pull their Jaccard down.
+// 0.1 keeps only pairs whose co-player overlap is a real fraction of their
+// combined audience.
+const minJaccard = 0.1
+
+// Worker periodically rebuilds the household co-play edge set. Pure local SQL,
+// so there are no rate limits — but the pair self-join is roughly
+// O(users × artists_per_user²), so it ticks slowly: co-listening shifts over
+// days, not minutes, and a frequent rebuild would burn CPU for no fresher
+// signal.
+type Worker struct {
+	pool   *pgxpool.Pool
+	logger *slog.Logger
+	tick   time.Duration
+}
+
+// NewWorker constructs a worker with the production default 6h tick.
+func NewWorker(pool *pgxpool.Pool, logger *slog.Logger) *Worker {
+	return &Worker{pool: pool, logger: logger, tick: 6 * time.Hour}
+}
+
+// Run rebuilds once at startup (so edges exist without waiting a full tick),
+// then every w.tick until ctx is cancelled. Runs in its own goroutine, so a
+// slow initial rebuild never blocks boot.
+func (w *Worker) Run(ctx context.Context) {
+	if err := w.rebuild(ctx); err != nil {
+		w.logger.Error("coplay: initial rebuild failed", "err", err)
+	}
+	t := time.NewTicker(w.tick)
+	defer t.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-t.C:
+			if err := w.rebuild(ctx); err != nil {
+				w.logger.Error("coplay: rebuild failed", "err", err)
+			}
+		}
+	}
+}
+
+// rebuild atomic-replaces the user_cooccurrence edge set inside one
+// transaction — delete the old edges, recompute from current play history — so
+// the candidate pool never observes a half-built set.
+func (w *Worker) rebuild(ctx context.Context) error {
+	tx, err := w.pool.Begin(ctx)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = tx.Rollback(ctx) }()
+	q := dbq.New(tx)
+	if err := q.DeleteArtistCoplayEdges(ctx); err != nil {
+		return err
+	}
+	if err := q.InsertArtistCoplayEdges(ctx, minJaccard); err != nil {
+		return err
+	}
+	if err := tx.Commit(ctx); err != nil {
+		return err
+	}
+	w.logger.Debug("coplay: edges rebuilt")
+	return nil
+}

internal/coplay/worker_integration_test.go

@@ -0,0 +1,162 @@
+package coplay
+
+import (
+	"context"
+	"io"
+	"log/slog"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/jackc/pgx/v5/pgtype"
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"git.fabledsword.com/bvandeusen/minstrel/internal/db"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/dbtest"
+)
+
+func testPool(t *testing.T) *pgxpool.Pool {
+	t.Helper()
+	if testing.Short() {
+		t.Skip("skipping in -short mode")
+	}
+	dsn := os.Getenv("MINSTREL_TEST_DATABASE_URL")
+	if dsn == "" {
+		t.Skip("MINSTREL_TEST_DATABASE_URL not set")
+	}
+	if err := db.Migrate(dsn, slog.New(slog.NewTextHandler(io.Discard, nil))); err != nil {
+		t.Fatalf("migrate: %v", err)
+	}
+	pool, err := pgxpool.New(context.Background(), dsn)
+	if err != nil {
+		t.Fatalf("pool: %v", err)
+	}
+	t.Cleanup(pool.Close)
+	dbtest.ResetDB(t, pool)
+	return pool
+}
+
+func discardLogger() *slog.Logger { return slog.New(slog.NewTextHandler(io.Discard, nil)) }
+
+func seedUser(t *testing.T, q *dbq.Queries, name string) pgtype.UUID {
+	t.Helper()
+	u, err := q.CreateUser(context.Background(), dbq.CreateUserParams{
+		Username: dbtest.TestUserPrefix + name, PasswordHash: "x", ApiToken: name + "-tok", IsAdmin: false,
+	})
+	if err != nil {
+		t.Fatalf("seed user %s: %v", name, err)
+	}
+	return u.ID
+}
+
+// seedArtistTrack creates an artist + album + one track, returning both ids.
+func seedArtistTrack(t *testing.T, q *dbq.Queries, name string) (pgtype.UUID, pgtype.UUID) {
+	t.Helper()
+	ctx := context.Background()
+	a, err := q.UpsertArtist(ctx, dbq.UpsertArtistParams{Name: name, SortName: name})
+	if err != nil {
+		t.Fatalf("seed artist: %v", err)
+	}
+	al, err := q.UpsertAlbum(ctx, dbq.UpsertAlbumParams{Title: name, SortTitle: name, ArtistID: a.ID})
+	if err != nil {
+		t.Fatalf("seed album: %v", err)
+	}
+	tr, err := q.UpsertTrack(ctx, dbq.UpsertTrackParams{
+		Title: name, AlbumID: al.ID, ArtistID: a.ID,
+		DurationMs: 1000, FilePath: "/tmp/coplay-" + name + ".mp3",
+		FileSize: 1, FileFormat: "mp3",
+	})
+	if err != nil {
+		t.Fatalf("seed track: %v", err)
+	}
+	return a.ID, tr.ID
+}
+
+func play(t *testing.T, pool *pgxpool.Pool, userID, trackID pgtype.UUID) {
+	t.Helper()
+	ctx := context.Background()
+	at := time.Now()
+	var sessionID pgtype.UUID
+	if err := pool.QueryRow(ctx,
+		`INSERT INTO play_sessions (user_id, started_at, last_event_at, client_id)
+		 VALUES ($1, $2, $2, 'coplay-test') RETURNING id`,
+		userID, at).Scan(&sessionID); err != nil {
+		t.Fatalf("insert play_session: %v", err)
+	}
+	if _, err := pool.Exec(ctx,
+		`INSERT INTO play_events (user_id, track_id, session_id, started_at, was_skipped)
+		 VALUES ($1, $2, $3, $4, false)`,
+		userID, trackID, sessionID, at); err != nil {
+		t.Fatalf("insert play_event: %v", err)
+	}
+}
+
+func coplayEdgeCount(t *testing.T, pool *pgxpool.Pool) int {
+	t.Helper()
+	var n int
+	if err := pool.QueryRow(context.Background(),
+		`SELECT count(*) FROM artist_similarity WHERE source='user_cooccurrence'`).Scan(&n); err != nil {
+		t.Fatalf("count edges: %v", err)
+	}
+	return n
+}
+
+// TestCoplayWorker_BuildsEdges: two users who both play two artists produce a
+// perfect-overlap co-play edge (Jaccard 1.0) in each direction.
+func TestCoplayWorker_BuildsEdges(t *testing.T) {
+	pool := testPool(t)
+	ctx := context.Background()
+	q := dbq.New(pool)
+
+	u1 := seedUser(t, q, "cop1")
+	u2 := seedUser(t, q, "cop2")
+	aA, tA := seedArtistTrack(t, q, "ArtA")
+	aB, tB := seedArtistTrack(t, q, "ArtB")
+
+	for _, u := range []pgtype.UUID{u1, u2} {
+		play(t, pool, u, tA)
+		play(t, pool, u, tB)
+	}
+
+	if err := NewWorker(pool, discardLogger()).rebuild(ctx); err != nil {
+		t.Fatalf("rebuild: %v", err)
+	}
+
+	var score float64
+	if err := pool.QueryRow(ctx,
+		`SELECT score FROM artist_similarity
+		 WHERE artist_a_id=$1 AND artist_b_id=$2 AND source='user_cooccurrence'`,
+		aA, aB).Scan(&score); err != nil {
+		t.Fatalf("expected co-play edge ArtA→ArtB: %v", err)
+	}
+	// Jaccard of perfectly-overlapping player sets (both users play both):
+	// coplayers=2, players each=2 → 2/(2+2-2) = 1.0.
+	if score != 1.0 {
+		t.Errorf("edge score = %v, want 1.0 (perfect overlap)", score)
+	}
+	if got := coplayEdgeCount(t, pool); got != 2 {
+		t.Errorf("edge count = %d, want 2 (A→B and B→A)", got)
+	}
+}
+
+// TestCoplayWorker_SingleUserNoEdges: one user's own co-listening yields no
+// edges — the >= 2 distinct-co-player gate keeps single-user servers empty.
+func TestCoplayWorker_SingleUserNoEdges(t *testing.T) {
+	pool := testPool(t)
+	ctx := context.Background()
+	q := dbq.New(pool)
+
+	u := seedUser(t, q, "solo")
+	_, tA := seedArtistTrack(t, q, "SoloA")
+	_, tB := seedArtistTrack(t, q, "SoloB")
+	play(t, pool, u, tA)
+	play(t, pool, u, tB)
+
+	if err := NewWorker(pool, discardLogger()).rebuild(ctx); err != nil {
+		t.Fatalf("rebuild: %v", err)
+	}
+	if got := coplayEdgeCount(t, pool); got != 0 {
+		t.Errorf("single-user edge count = %d, want 0 (>= 2 co-player gate)", got)
+	}
+}

internal/db/dbq/coplay.sql.go

@@ -0,0 +1,78 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.31.1
+// source: coplay.sql
+
+package dbq
+
+import (
+	"context"
+)
+
+const deleteArtistCoplayEdges = `-- name: DeleteArtistCoplayEdges :exec
+
+DELETE FROM artist_similarity WHERE source = 'user_cooccurrence'
+`
+
+// Household co-play similarity (#1533, milestone #160 Opt 5). Minstrel is a
+// single shared-library, multi-user server (no per-user library ACL), so the
+// "household" is the whole instance's user set. These queries recompute
+// artist–artist co-occurrence edges from play_events and store them in
+// artist_similarity under the pre-provisioned source = 'user_cooccurrence'
+// (whitelisted in the 0009 CHECK from day one). A periodic worker DELETEs then
+// re-INSERTs so edges that fall below threshold disappear. Single-user servers
+// produce no edges (the >= 2 co-player gate), so the arm is empty there.
+func (q *Queries) DeleteArtistCoplayEdges(ctx context.Context) error {
+	_, err := q.db.Exec(ctx, deleteArtistCoplayEdges)
+	return err
+}
+
+const insertArtistCoplayEdges = `-- name: InsertArtistCoplayEdges :exec
+WITH user_artists AS (
+    SELECT DISTINCT pe.user_id, t.artist_id
+    FROM play_events pe
+    JOIN tracks t ON t.id = pe.track_id
+    WHERE pe.was_skipped = false
+      AND pe.started_at > now() - interval '365 days'
+),
+artist_players AS (
+    SELECT artist_id, count(*)::float8 AS players
+    FROM user_artists
+    GROUP BY artist_id
+),
+pairs AS (
+    SELECT ua.artist_id AS a_id,
+           ub.artist_id AS b_id,
+           count(*)::float8 AS coplayers
+    FROM user_artists ua
+    JOIN user_artists ub
+      ON ua.user_id = ub.user_id AND ua.artist_id <> ub.artist_id
+    GROUP BY ua.artist_id, ub.artist_id
+    HAVING count(*) >= 2
+),
+scored AS (
+    SELECT p.a_id, p.b_id,
+           p.coplayers / (pa.players + pb.players - p.coplayers) AS score
+    FROM pairs p
+    JOIN artist_players pa ON pa.artist_id = p.a_id
+    JOIN artist_players pb ON pb.artist_id = p.b_id
+)
+INSERT INTO artist_similarity (artist_a_id, artist_b_id, score, source, fetched_at)
+SELECT a_id, b_id, score, 'user_cooccurrence', now()
+FROM scored
+WHERE score >= $1
+ON CONFLICT (artist_a_id, artist_b_id, source)
+DO UPDATE SET score = EXCLUDED.score, fetched_at = EXCLUDED.fetched_at
+`
+
+// Two artists are "co-played" when the same users play both. score is the
+// Jaccard of their distinct-player sets — coplayers / (playersA + playersB −
+// coplayers) in (0,1] — which controls for globally-popular artists (an artist
+// everyone plays would otherwise co-occur with everything). Only pairs with
+// >= 2 distinct co-players AND Jaccard >= $1 (a floor that both prunes weak
+// edges and self-limits hub artists, whose large denominators drag their
+// Jaccard down) are kept. Completed plays only, 365-day window.
+func (q *Queries) InsertArtistCoplayEdges(ctx context.Context, score float64) error {
+	_, err := q.db.Exec(ctx, insertArtistCoplayEdges, score)
+	return err
+}

internal/db/dbq/events.sql.go

@@ -54,7 +54,7 @@ func (q *Queries) GetMostRecentPlaySessionForUser(ctx context.Context, userID pg
 }
 
 const getOpenPlayEventForUser = `-- name: GetOpenPlayEventForUser :one
-SELECT id, user_id, track_id, session_id, started_at, ended_at, duration_played_ms, completion_ratio, was_skipped, client_id, session_vector_at_play, scrobbled_at, source, pick_kind FROM play_events
+SELECT id, user_id, track_id, session_id, started_at, ended_at, duration_played_ms, completion_ratio, was_skipped, client_id, session_vector_at_play, scrobbled_at, source, pick_kind, device_class FROM play_events
 WHERE user_id = $1 AND ended_at IS NULL
 ORDER BY started_at DESC
 LIMIT 1
@@ -80,12 +80,13 @@ func (q *Queries) GetOpenPlayEventForUser(ctx context.Context, userID pgtype.UUI
 		&i.ScrobbledAt,
 		&i.Source,
 		&i.PickKind,
+		&i.DeviceClass,
 	)
 	return i, err
 }
 
 const getPlayEventByID = `-- name: GetPlayEventByID :one
-SELECT id, user_id, track_id, session_id, started_at, ended_at, duration_played_ms, completion_ratio, was_skipped, client_id, session_vector_at_play, scrobbled_at, source, pick_kind FROM play_events WHERE id = $1
+SELECT id, user_id, track_id, session_id, started_at, ended_at, duration_played_ms, completion_ratio, was_skipped, client_id, session_vector_at_play, scrobbled_at, source, pick_kind, device_class FROM play_events WHERE id = $1
 `
 
 func (q *Queries) GetPlayEventByID(ctx context.Context, id pgtype.UUID) (PlayEvent, error) {
@@ -106,6 +107,7 @@ func (q *Queries) GetPlayEventByID(ctx context.Context, id pgtype.UUID) (PlayEve
 		&i.ScrobbledAt,
 		&i.Source,
 		&i.PickKind,
+		&i.DeviceClass,
 	)
 	return i, err
 }
@@ -144,19 +146,22 @@ func (q *Queries) GetSystemPickKindForTrack(ctx context.Context, arg GetSystemPi
 
 const insertPlayEvent = `-- name: InsertPlayEvent :one
 INSERT INTO play_events (
-    user_id, track_id, session_id, started_at, client_id, source, pick_kind
-) VALUES ($1, $2, $3, $4, $5, $6, $7::text)
-RETURNING id, user_id, track_id, session_id, started_at, ended_at, duration_played_ms, completion_ratio, was_skipped, client_id, session_vector_at_play, scrobbled_at, source, pick_kind
+    user_id, track_id, session_id, started_at, client_id, source, pick_kind,
+    device_class
+) VALUES ($1, $2, $3, $4, $5, $6, $7::text,
+    $8::text)
+RETURNING id, user_id, track_id, session_id, started_at, ended_at, duration_played_ms, completion_ratio, was_skipped, client_id, session_vector_at_play, scrobbled_at, source, pick_kind, device_class
 `
 
 type InsertPlayEventParams struct {
-	UserID    pgtype.UUID
-	TrackID   pgtype.UUID
-	SessionID pgtype.UUID
-	StartedAt pgtype.Timestamptz
-	ClientID  *string
-	Source    *string
-	PickKind  *string
+	UserID      pgtype.UUID
+	TrackID     pgtype.UUID
+	SessionID   pgtype.UUID
+	StartedAt   pgtype.Timestamptz
+	ClientID    *string
+	Source      *string
+	PickKind    *string
+	DeviceClass *string
 }
 
 // pick_kind is non-NULL only for system-playlist plays whose track was
@@ -171,6 +176,7 @@ func (q *Queries) InsertPlayEvent(ctx context.Context, arg InsertPlayEventParams
 		arg.ClientID,
 		arg.Source,
 		arg.PickKind,
+		arg.DeviceClass,
 	)
 	var i PlayEvent
 	err := row.Scan(
@@ -188,6 +194,7 @@ func (q *Queries) InsertPlayEvent(ctx context.Context, arg InsertPlayEventParams
 		&i.ScrobbledAt,
 		&i.Source,
 		&i.PickKind,
+		&i.DeviceClass,
 	)
 	return i, err
 }
@@ -333,7 +340,7 @@ SET ended_at = $2,
     completion_ratio = $4,
     was_skipped = $5
 WHERE id = $1
-RETURNING id, user_id, track_id, session_id, started_at, ended_at, duration_played_ms, completion_ratio, was_skipped, client_id, session_vector_at_play, scrobbled_at, source, pick_kind
+RETURNING id, user_id, track_id, session_id, started_at, ended_at, duration_played_ms, completion_ratio, was_skipped, client_id, session_vector_at_play, scrobbled_at, source, pick_kind, device_class
 `
 
 type UpdatePlayEventEndedParams struct {
@@ -371,6 +378,7 @@ func (q *Queries) UpdatePlayEventEnded(ctx context.Context, arg UpdatePlayEventE
 		&i.ScrobbledAt,
 		&i.Source,
 		&i.PickKind,
+		&i.DeviceClass,
 	)
 	return i, err
 }

internal/db/dbq/models.go

@@ -384,6 +384,7 @@ type PlayEvent struct {
 	ScrobbledAt         pgtype.Timestamptz
 	Source              *string
 	PickKind            *string
+	DeviceClass         *string
 }
 
 type PlaySession struct {
@@ -446,16 +447,17 @@ type RecommendationTuningAudit struct {
 }
 
 type RecommendationWeightProfile struct {
-	Profile          string
-	BaseWeight       float64
-	LikeBoost        float64
-	RecencyWeight    float64
-	SkipPenalty      float64
-	JitterMagnitude  float64
-	ContextWeight    float64
-	SimilarityWeight float64
-	TasteWeight      float64
-	UpdatedAt        pgtype.Timestamptz
+	Profile           string
+	BaseWeight        float64
+	LikeBoost         float64
+	RecencyWeight     float64
+	SkipPenalty       float64
+	JitterMagnitude   float64
+	ContextWeight     float64
+	SimilarityWeight  float64
+	TasteWeight       float64
+	UpdatedAt         pgtype.Timestamptz
+	ContextTimeWeight float64
 }
 
 type RegistrationSetting struct {
@@ -554,6 +556,20 @@ type TasteProfileArtist struct {
 	UpdatedAt pgtype.Timestamptz
 }
 
+type TasteProfileEra struct {
+	UserID    pgtype.UUID
+	Era       string
+	Weight    float64
+	UpdatedAt pgtype.Timestamptz
+}
+
+type TasteProfileMood struct {
+	UserID    pgtype.UUID
+	Mood      string
+	Weight    float64
+	UpdatedAt pgtype.Timestamptz
+}
+
 type TasteProfileTag struct {
 	UserID    pgtype.UUID
 	Tag       string
@@ -568,6 +584,9 @@ type TasteTuning struct {
 	EngagementNeutral  float64
 	EngagementFull     float64
 	UpdatedAt          pgtype.Timestamptz
+	EnrichedTagScale   float64
+	EraScale           float64
+	MoodScale          float64
 }
 
 type Track struct {

internal/db/dbq/recommendation.sql.go

@@ -11,6 +11,110 @@ import (
 	"github.com/jackc/pgx/v5/pgtype"
 )
 
+const getLatestPlayDeviceClassForUser = `-- name: GetLatestPlayDeviceClassForUser :one
+SELECT device_class
+FROM play_events
+WHERE user_id = $1
+ORDER BY started_at DESC
+LIMIT 1
+`
+
+// The device_class of the user's most recent play (#1551), used as the
+// "current device" for radio context conditioning. NULL when the latest play
+// predates device capture or came from a client that didn't send one.
+func (q *Queries) GetLatestPlayDeviceClassForUser(ctx context.Context, userID pgtype.UUID) (*string, error) {
+	row := q.db.QueryRow(ctx, getLatestPlayDeviceClassForUser, userID)
+	var device_class *string
+	err := row.Scan(&device_class)
+	return device_class, err
+}
+
+const listArtistContextPlayCountsForUser = `-- name: ListArtistContextPlayCountsForUser :many
+WITH tz AS (
+    SELECT COALESCE(NULLIF(u.timezone, ''), 'UTC') AS zone
+    FROM users u WHERE u.id = $1
+),
+now_cell AS (
+    SELECT
+        CASE
+            WHEN EXTRACT(hour FROM now() AT TIME ZONE tz.zone) < 5  THEN 3
+            WHEN EXTRACT(hour FROM now() AT TIME ZONE tz.zone) < 12 THEN 0
+            WHEN EXTRACT(hour FROM now() AT TIME ZONE tz.zone) < 17 THEN 1
+            WHEN EXTRACT(hour FROM now() AT TIME ZONE tz.zone) < 22 THEN 2
+            ELSE 3
+        END AS daypart,
+        (EXTRACT(isodow FROM now() AT TIME ZONE tz.zone) >= 6) AS is_weekend
+    FROM tz
+),
+plays AS (
+    SELECT t.artist_id,
+           pe.device_class,
+           CASE
+               WHEN EXTRACT(hour FROM pe.started_at AT TIME ZONE tz.zone) < 5  THEN 3
+               WHEN EXTRACT(hour FROM pe.started_at AT TIME ZONE tz.zone) < 12 THEN 0
+               WHEN EXTRACT(hour FROM pe.started_at AT TIME ZONE tz.zone) < 17 THEN 1
+               WHEN EXTRACT(hour FROM pe.started_at AT TIME ZONE tz.zone) < 22 THEN 2
+               ELSE 3
+           END AS daypart,
+           (EXTRACT(isodow FROM pe.started_at AT TIME ZONE tz.zone) >= 6) AS is_weekend
+    FROM play_events pe
+    JOIN tracks t ON t.id = pe.track_id
+    CROSS JOIN tz
+    WHERE pe.user_id = $1
+      AND pe.was_skipped = false
+      AND pe.started_at > now() - interval '365 days'
+)
+SELECT p.artist_id,
+       count(*) AS total_plays,
+       count(*) FILTER (
+           WHERE p.daypart = (SELECT daypart FROM now_cell)
+             AND p.is_weekend = (SELECT is_weekend FROM now_cell)
+             AND ($2::text = '' OR p.device_class = $2::text)
+       ) AS cell_plays
+FROM plays p
+GROUP BY p.artist_id
+`
+
+type ListArtistContextPlayCountsForUserParams struct {
+	ID      pgtype.UUID
+	Column2 string
+}
+
+type ListArtistContextPlayCountsForUserRow struct {
+	ArtistID   pgtype.UUID
+	TotalPlays int64
+	CellPlays  int64
+}
+
+// Per-artist completed-play counts split by whether each play falls in the
+// CURRENT context cell, in the user's local timezone (#1531). The cell is
+// daypart × weekday-type, optionally narrowed by device class (#1551): when
+// $2 (the current device) is ”, the device dimension is ignored (identical to
+// the time-only #1531 behaviour, used by the daily mixes which have no device);
+// when $2 is set (radio), a play only counts in the cell if its device_class
+// matches. Feeds the context-affinity scoring term. Skips excluded; a 365-day
+// window bounds cost. Daypart buckets: night [22,5) morning [5,12)
+// afternoon [12,17) evening [17,22). Weekend = ISO days 6–7 (Sat/Sun).
+func (q *Queries) ListArtistContextPlayCountsForUser(ctx context.Context, arg ListArtistContextPlayCountsForUserParams) ([]ListArtistContextPlayCountsForUserRow, error) {
+	rows, err := q.db.Query(ctx, listArtistContextPlayCountsForUser, arg.ID, arg.Column2)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var items []ListArtistContextPlayCountsForUserRow
+	for rows.Next() {
+		var i ListArtistContextPlayCountsForUserRow
+		if err := rows.Scan(&i.ArtistID, &i.TotalPlays, &i.CellPlays); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
 const listLastPlayedArtistsForUser = `-- name: ListLastPlayedArtistsForUser :many
 WITH user_plays AS (
     SELECT t.artist_id, max(pe.started_at) AS last_started
@@ -585,8 +689,10 @@ SELECT
     (l.user_id IS NOT NULL)::bool AS is_liked,
     pe.last_played_at::timestamptz AS last_played_at,
     pe.play_count,
-    pe.skip_count
+    pe.skip_count,
+    al.release_date AS release_date
 FROM tracks t
+JOIN albums al ON al.id = t.album_id
 LEFT JOIN general_likes l ON l.user_id = $1 AND l.track_id = t.id
 LEFT JOIN LATERAL (
     SELECT
@@ -620,6 +726,7 @@ type LoadRadioCandidatesRow struct {
 	LastPlayedAt pgtype.Timestamptz
 	PlayCount    int64
 	SkipCount    int64
+	ReleaseDate  pgtype.Date
 }
 
 // Returns all tracks except the seed and any played by the user within
@@ -660,6 +767,7 @@ func (q *Queries) LoadRadioCandidates(ctx context.Context, arg LoadRadioCandidat
 			&i.LastPlayedAt,
 			&i.PlayCount,
 			&i.SkipCount,
+			&i.ReleaseDate,
 		); err != nil {
 			return nil, err
 		}
@@ -754,6 +862,22 @@ taste_overlap AS (
     ORDER BY tpa.weight DESC, t.id
     LIMIT $10
 ),
+coplay_artists AS (
+    -- Household co-play (#1533): tracks by artists co-played across the
+    -- instance with the seed's artist (source='user_cooccurrence', built by
+    -- the coplay worker). Mirrors similar_artists but from local co-occurrence
+    -- instead of ListenBrainz; empty on single-user servers. Same 0.5 damp as
+    -- similar_artists since it's artist-level.
+    SELECT t.id AS track_id, asim.score * 0.5 AS sim_score
+    FROM artist_similarity asim
+    JOIN tracks t ON t.artist_id = asim.artist_b_id
+    JOIN seed_artist sa ON asim.artist_a_id = sa.artist_id
+    WHERE asim.source = 'user_cooccurrence'
+      AND t.id NOT IN (SELECT id FROM excluded_ids)
+      AND t.id <> $2
+    ORDER BY asim.score DESC, random()
+    LIMIT $11
+),
 random_fill AS (
     SELECT t.id AS track_id, 0.0::float8 AS sim_score
     FROM tracks t
@@ -765,6 +889,7 @@ random_fill AS (
           UNION SELECT track_id FROM tag_overlap
           UNION SELECT track_id FROM likes_overlap
           UNION SELECT track_id FROM taste_overlap
+          UNION SELECT track_id FROM coplay_artists
       )
     ORDER BY random()
     LIMIT $9
@@ -775,6 +900,7 @@ SELECT
     pe.last_played_at::timestamptz AS last_played_at,
     pe.play_count,
     pe.skip_count,
+    al.release_date AS release_date,
     COALESCE(max(u.sim_score), 0.0) AS similarity_score
 FROM (
     SELECT track_id, sim_score FROM lb_similar
@@ -782,9 +908,11 @@ FROM (
     UNION ALL SELECT track_id, sim_score FROM tag_overlap
     UNION ALL SELECT track_id, sim_score FROM likes_overlap
     UNION ALL SELECT track_id, sim_score FROM taste_overlap
+    UNION ALL SELECT track_id, sim_score FROM coplay_artists
     UNION ALL SELECT track_id, sim_score FROM random_fill
 ) u
 JOIN tracks t ON t.id = u.track_id
+JOIN albums al ON al.id = t.album_id
 LEFT JOIN general_likes l ON l.user_id = $1 AND l.track_id = t.id
 LEFT JOIN LATERAL (
     SELECT max(started_at) AS last_played_at,
@@ -796,7 +924,8 @@ LEFT JOIN LATERAL (
 GROUP BY t.id, t.title, t.album_id, t.artist_id, t.duration_ms, t.file_path,
          t.file_format, t.file_size, t.bitrate, t.track_number, t.disc_number,
          t.mbid, t.genre, t.added_at, t.updated_at,
-         l.user_id, pe.last_played_at, pe.play_count, pe.skip_count
+         l.user_id, pe.last_played_at, pe.play_count, pe.skip_count,
+         al.release_date
 `
 
 type LoadRadioCandidatesV2Params struct {
@@ -810,6 +939,7 @@ type LoadRadioCandidatesV2Params struct {
 	Limit_4 int32
 	Limit_5 int32
 	Limit_6 int32
+	Limit_7 int32
 }
 
 type LoadRadioCandidatesV2Row struct {
@@ -818,6 +948,7 @@ type LoadRadioCandidatesV2Row struct {
 	LastPlayedAt    pgtype.Timestamptz
 	PlayCount       int64
 	SkipCount       int64
+	ReleaseDate     pgtype.Date
 	SimilarityScore interface{}
 }
 
@@ -829,7 +960,9 @@ type LoadRadioCandidatesV2Row struct {
 //	$10 taste_overlap K (#796 phase 2b — tracks by the user's top
 //	positively-weighted taste-profile artists, so taste-relevant tracks
 //	enter the pool even when the similarity/random arms miss them; scored
-//	in Go via TasteMatch, so sim_score here is 0 pool-inclusion).
+//	in Go via TasteMatch, so sim_score here is 0 pool-inclusion),
+//	$11 coplay_artists K (#1533 — tracks by artists co-played across the
+//	instance with the seed's artist; source='user_cooccurrence').
 //
 // Returns same shape as LoadRadioCandidates plus similarity_score column.
 func (q *Queries) LoadRadioCandidatesV2(ctx context.Context, arg LoadRadioCandidatesV2Params) ([]LoadRadioCandidatesV2Row, error) {
@@ -844,6 +977,7 @@ func (q *Queries) LoadRadioCandidatesV2(ctx context.Context, arg LoadRadioCandid
 		arg.Limit_4,
 		arg.Limit_5,
 		arg.Limit_6,
+		arg.Limit_7,
 	)
 	if err != nil {
 		return nil, err
@@ -874,6 +1008,7 @@ func (q *Queries) LoadRadioCandidatesV2(ctx context.Context, arg LoadRadioCandid
 			&i.LastPlayedAt,
 			&i.PlayCount,
 			&i.SkipCount,
+			&i.ReleaseDate,
 			&i.SimilarityScore,
 		); err != nil {
 			return nil, err

internal/db/dbq/recommendation_tuning.sql.go

@@ -10,7 +10,7 @@ import (
 )
 
 const getTasteTuning = `-- name: GetTasteTuning :one
-SELECT singleton, half_life_days, engagement_hard_skip, engagement_neutral, engagement_full, updated_at FROM taste_tuning WHERE singleton = true
+SELECT singleton, half_life_days, engagement_hard_skip, engagement_neutral, engagement_full, updated_at, enriched_tag_scale, era_scale, mood_scale FROM taste_tuning WHERE singleton = true
 `
 
 func (q *Queries) GetTasteTuning(ctx context.Context) (TasteTuning, error) {
@@ -23,6 +23,9 @@ func (q *Queries) GetTasteTuning(ctx context.Context) (TasteTuning, error) {
 		&i.EngagementNeutral,
 		&i.EngagementFull,
 		&i.UpdatedAt,
+		&i.EnrichedTagScale,
+		&i.EraScale,
+		&i.MoodScale,
 	)
 	return i, err
 }
@@ -80,7 +83,7 @@ func (q *Queries) ListTuningAudit(ctx context.Context, limit int32) ([]Recommend
 }
 
 const listWeightProfiles = `-- name: ListWeightProfiles :many
-SELECT profile, base_weight, like_boost, recency_weight, skip_penalty, jitter_magnitude, context_weight, similarity_weight, taste_weight, updated_at FROM recommendation_weight_profiles ORDER BY profile
+SELECT profile, base_weight, like_boost, recency_weight, skip_penalty, jitter_magnitude, context_weight, similarity_weight, taste_weight, updated_at, context_time_weight FROM recommendation_weight_profiles ORDER BY profile
 `
 
 func (q *Queries) ListWeightProfiles(ctx context.Context) ([]RecommendationWeightProfile, error) {
@@ -103,6 +106,7 @@ func (q *Queries) ListWeightProfiles(ctx context.Context) ([]RecommendationWeigh
 			&i.SimilarityWeight,
 			&i.TasteWeight,
 			&i.UpdatedAt,
+			&i.ContextTimeWeight,
 		); err != nil {
 			return nil, err
 		}
@@ -120,9 +124,12 @@ UPDATE taste_tuning
        engagement_hard_skip = $2,
        engagement_neutral   = $3,
        engagement_full      = $4,
+       enriched_tag_scale   = $5,
+       era_scale            = $6,
+       mood_scale           = $7,
        updated_at           = now()
  WHERE singleton = true
-RETURNING singleton, half_life_days, engagement_hard_skip, engagement_neutral, engagement_full, updated_at
+RETURNING singleton, half_life_days, engagement_hard_skip, engagement_neutral, engagement_full, updated_at, enriched_tag_scale, era_scale, mood_scale
 `
 
 type UpdateTasteTuningParams struct {
@@ -130,6 +137,9 @@ type UpdateTasteTuningParams struct {
 	EngagementHardSkip float64
 	EngagementNeutral  float64
 	EngagementFull     float64
+	EnrichedTagScale   float64
+	EraScale           float64
+	MoodScale          float64
 }
 
 func (q *Queries) UpdateTasteTuning(ctx context.Context, arg UpdateTasteTuningParams) (TasteTuning, error) {
@@ -138,6 +148,9 @@ func (q *Queries) UpdateTasteTuning(ctx context.Context, arg UpdateTasteTuningPa
 		arg.EngagementHardSkip,
 		arg.EngagementNeutral,
 		arg.EngagementFull,
+		arg.EnrichedTagScale,
+		arg.EraScale,
+		arg.MoodScale,
 	)
 	var i TasteTuning
 	err := row.Scan(
@@ -147,35 +160,40 @@ func (q *Queries) UpdateTasteTuning(ctx context.Context, arg UpdateTasteTuningPa
 		&i.EngagementNeutral,
 		&i.EngagementFull,
 		&i.UpdatedAt,
+		&i.EnrichedTagScale,
+		&i.EraScale,
+		&i.MoodScale,
 	)
 	return i, err
 }
 
 const updateWeightProfile = `-- name: UpdateWeightProfile :one
 UPDATE recommendation_weight_profiles
-   SET base_weight       = $2,
-       like_boost        = $3,
-       recency_weight    = $4,
-       skip_penalty      = $5,
-       jitter_magnitude  = $6,
-       context_weight    = $7,
-       similarity_weight = $8,
-       taste_weight      = $9,
-       updated_at        = now()
+   SET base_weight         = $2,
+       like_boost          = $3,
+       recency_weight      = $4,
+       skip_penalty        = $5,
+       jitter_magnitude    = $6,
+       context_weight      = $7,
+       similarity_weight   = $8,
+       taste_weight        = $9,
+       context_time_weight = $10,
+       updated_at          = now()
  WHERE profile = $1
-RETURNING profile, base_weight, like_boost, recency_weight, skip_penalty, jitter_magnitude, context_weight, similarity_weight, taste_weight, updated_at
+RETURNING profile, base_weight, like_boost, recency_weight, skip_penalty, jitter_magnitude, context_weight, similarity_weight, taste_weight, updated_at, context_time_weight
 `
 
 type UpdateWeightProfileParams struct {
-	Profile          string
-	BaseWeight       float64
-	LikeBoost        float64
-	RecencyWeight    float64
-	SkipPenalty      float64
-	JitterMagnitude  float64
-	ContextWeight    float64
-	SimilarityWeight float64
-	TasteWeight      float64
+	Profile           string
+	BaseWeight        float64
+	LikeBoost         float64
+	RecencyWeight     float64
+	SkipPenalty       float64
+	JitterMagnitude   float64
+	ContextWeight     float64
+	SimilarityWeight  float64
+	TasteWeight       float64
+	ContextTimeWeight float64
 }
 
 func (q *Queries) UpdateWeightProfile(ctx context.Context, arg UpdateWeightProfileParams) (RecommendationWeightProfile, error) {
@@ -189,6 +207,7 @@ func (q *Queries) UpdateWeightProfile(ctx context.Context, arg UpdateWeightProfi
 		arg.ContextWeight,
 		arg.SimilarityWeight,
 		arg.TasteWeight,
+		arg.ContextTimeWeight,
 	)
 	var i RecommendationWeightProfile
 	err := row.Scan(
@@ -202,6 +221,7 @@ func (q *Queries) UpdateWeightProfile(ctx context.Context, arg UpdateWeightProfi
 		&i.SimilarityWeight,
 		&i.TasteWeight,
 		&i.UpdatedAt,
+		&i.ContextTimeWeight,
 	)
 	return i, err
 }
@@ -209,8 +229,9 @@ func (q *Queries) UpdateWeightProfile(ctx context.Context, arg UpdateWeightProfi
 const upsertTasteTuningDefaults = `-- name: UpsertTasteTuningDefaults :exec
 INSERT INTO taste_tuning (
     singleton, half_life_days, engagement_hard_skip,
-    engagement_neutral, engagement_full
-) VALUES (true, $1, $2, $3, $4)
+    engagement_neutral, engagement_full, enriched_tag_scale, era_scale,
+    mood_scale
+) VALUES (true, $1, $2, $3, $4, $5, $6, $7)
 ON CONFLICT (singleton) DO NOTHING
 `
 
@@ -219,6 +240,9 @@ type UpsertTasteTuningDefaultsParams struct {
 	EngagementHardSkip float64
 	EngagementNeutral  float64
 	EngagementFull     float64
+	EnrichedTagScale   float64
+	EraScale           float64
+	MoodScale          float64
 }
 
 func (q *Queries) UpsertTasteTuningDefaults(ctx context.Context, arg UpsertTasteTuningDefaultsParams) error {
@@ -227,6 +251,9 @@ func (q *Queries) UpsertTasteTuningDefaults(ctx context.Context, arg UpsertTaste
 		arg.EngagementHardSkip,
 		arg.EngagementNeutral,
 		arg.EngagementFull,
+		arg.EnrichedTagScale,
+		arg.EraScale,
+		arg.MoodScale,
 	)
 	return err
 }
@@ -235,21 +262,23 @@ const upsertWeightProfileDefaults = `-- name: UpsertWeightProfileDefaults :exec
 
 INSERT INTO recommendation_weight_profiles (
     profile, base_weight, like_boost, recency_weight, skip_penalty,
-    jitter_magnitude, context_weight, similarity_weight, taste_weight
-) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
+    jitter_magnitude, context_weight, similarity_weight, taste_weight,
+    context_time_weight
+) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)
 ON CONFLICT (profile) DO NOTHING
 `
 
 type UpsertWeightProfileDefaultsParams struct {
-	Profile          string
-	BaseWeight       float64
-	LikeBoost        float64
-	RecencyWeight    float64
-	SkipPenalty      float64
-	JitterMagnitude  float64
-	ContextWeight    float64
-	SimilarityWeight float64
-	TasteWeight      float64
+	Profile           string
+	BaseWeight        float64
+	LikeBoost         float64
+	RecencyWeight     float64
+	SkipPenalty       float64
+	JitterMagnitude   float64
+	ContextWeight     float64
+	SimilarityWeight  float64
+	TasteWeight       float64
+	ContextTimeWeight float64
 }
 
 // Recommendation tuning lab queries (#1250). Seeding happens via the
@@ -267,6 +296,7 @@ func (q *Queries) UpsertWeightProfileDefaults(ctx context.Context, arg UpsertWei
 		arg.ContextWeight,
 		arg.SimilarityWeight,
 		arg.TasteWeight,
+		arg.ContextTimeWeight,
 	)
 	return err
 }

internal/db/dbq/taste_profile.sql.go

@@ -20,6 +20,24 @@ func (q *Queries) DeleteTasteProfileArtistsForUser(ctx context.Context, userID p
 	return err
 }
 
+const deleteTasteProfileErasForUser = `-- name: DeleteTasteProfileErasForUser :exec
+DELETE FROM taste_profile_eras WHERE user_id = $1
+`
+
+func (q *Queries) DeleteTasteProfileErasForUser(ctx context.Context, userID pgtype.UUID) error {
+	_, err := q.db.Exec(ctx, deleteTasteProfileErasForUser, userID)
+	return err
+}
+
+const deleteTasteProfileMoodsForUser = `-- name: DeleteTasteProfileMoodsForUser :exec
+DELETE FROM taste_profile_moods WHERE user_id = $1
+`
+
+func (q *Queries) DeleteTasteProfileMoodsForUser(ctx context.Context, userID pgtype.UUID) error {
+	_, err := q.db.Exec(ctx, deleteTasteProfileMoodsForUser, userID)
+	return err
+}
+
 const deleteTasteProfileTagsForUser = `-- name: DeleteTasteProfileTagsForUser :exec
 DELETE FROM taste_profile_tags WHERE user_id = $1
 `
@@ -45,6 +63,38 @@ func (q *Queries) InsertTasteProfileArtist(ctx context.Context, arg InsertTasteP
 	return err
 }
 
+const insertTasteProfileEra = `-- name: InsertTasteProfileEra :exec
+INSERT INTO taste_profile_eras (user_id, era, weight)
+VALUES ($1, $2, $3)
+`
+
+type InsertTasteProfileEraParams struct {
+	UserID pgtype.UUID
+	Era    string
+	Weight float64
+}
+
+func (q *Queries) InsertTasteProfileEra(ctx context.Context, arg InsertTasteProfileEraParams) error {
+	_, err := q.db.Exec(ctx, insertTasteProfileEra, arg.UserID, arg.Era, arg.Weight)
+	return err
+}
+
+const insertTasteProfileMood = `-- name: InsertTasteProfileMood :exec
+INSERT INTO taste_profile_moods (user_id, mood, weight)
+VALUES ($1, $2, $3)
+`
+
+type InsertTasteProfileMoodParams struct {
+	UserID pgtype.UUID
+	Mood   string
+	Weight float64
+}
+
+func (q *Queries) InsertTasteProfileMood(ctx context.Context, arg InsertTasteProfileMoodParams) error {
+	_, err := q.db.Exec(ctx, insertTasteProfileMood, arg.UserID, arg.Mood, arg.Weight)
+	return err
+}
+
 const insertTasteProfileTag = `-- name: InsertTasteProfileTag :exec
 INSERT INTO taste_profile_tags (user_id, tag, weight)
 VALUES ($1, $2, $3)
@@ -87,21 +137,23 @@ func (q *Queries) ListLikedArtistIDsForUser(ctx context.Context, userID pgtype.U
 }
 
 const listLikedTrackTasteInputsForUser = `-- name: ListLikedTrackTasteInputsForUser :many
-SELECT t.id AS track_id, t.artist_id, t.genre
+SELECT t.id AS track_id, t.artist_id, t.genre, a.release_date
 FROM general_likes gl
 JOIN tracks t ON t.id = gl.track_id
+JOIN albums a ON a.id = t.album_id
 WHERE gl.user_id = $1
 `
 
 type ListLikedTrackTasteInputsForUserRow struct {
-	TrackID  pgtype.UUID
-	ArtistID pgtype.UUID
-	Genre    *string
+	TrackID     pgtype.UUID
+	ArtistID    pgtype.UUID
+	Genre       *string
+	ReleaseDate pgtype.Date
 }
 
-// (track_id, artist_id, genre) for each track the user has explicitly
-// liked. Feeds the track-like bonus into the liked track's artist and
-// tags; track_id keys the enriched track_tags lookup (#1490).
+// (track_id, artist_id, genre, release_date) for each track the user has
+// explicitly liked. Feeds the track-like bonus into the liked track's artist,
+// tags, and era (#1530); track_id keys the enriched track_tags lookup (#1490).
 func (q *Queries) ListLikedTrackTasteInputsForUser(ctx context.Context, userID pgtype.UUID) ([]ListLikedTrackTasteInputsForUserRow, error) {
 	rows, err := q.db.Query(ctx, listLikedTrackTasteInputsForUser, userID)
 	if err != nil {
@@ -111,7 +163,12 @@ func (q *Queries) ListLikedTrackTasteInputsForUser(ctx context.Context, userID p
 	var items []ListLikedTrackTasteInputsForUserRow
 	for rows.Next() {
 		var i ListLikedTrackTasteInputsForUserRow
-		if err := rows.Scan(&i.TrackID, &i.ArtistID, &i.Genre); err != nil {
+		if err := rows.Scan(
+			&i.TrackID,
+			&i.ArtistID,
+			&i.Genre,
+			&i.ReleaseDate,
+		); err != nil {
 			return nil, err
 		}
 		items = append(items, i)
@@ -128,6 +185,7 @@ SELECT
     t.id AS track_id,
     t.artist_id,
     t.genre,
+    a.release_date,
     LEAST(GREATEST(
         COALESCE(pe.completion_ratio,
                  pe.duration_played_ms::float8 / NULLIF(t.duration_ms, 0),
@@ -135,6 +193,7 @@ SELECT
     (EXTRACT(epoch FROM now() - pe.started_at) / 86400.0)::float8 AS age_days
 FROM play_events pe
 JOIN tracks t ON t.id = pe.track_id
+JOIN albums a ON a.id = t.album_id
 WHERE pe.user_id = $1
   AND pe.started_at > now() - ($2::float8 * INTERVAL '1 day')
   AND NOT EXISTS (
@@ -149,11 +208,12 @@ type ListPlayEngagementInputsForUserParams struct {
 }
 
 type ListPlayEngagementInputsForUserRow struct {
-	TrackID    pgtype.UUID
-	ArtistID   pgtype.UUID
-	Genre      *string
-	Completion float64
-	AgeDays    float64
+	TrackID     pgtype.UUID
+	ArtistID    pgtype.UUID
+	Genre       *string
+	ReleaseDate pgtype.Date
+	Completion  float64
+	AgeDays     float64
 }
 
 // Taste profile (#796 phase 1). The daily build computes signed artist/tag
@@ -162,7 +222,8 @@ type ListPlayEngagementInputsForUserRow struct {
 // One row per play in the decay-relevant window. completion is the play's
 // completion ratio (precomputed column when present, else duration_played /
 // track duration, clamped to [0,1]); age_days drives the time-decay. Genre
-// is split into tags in Go. Quarantined tracks are excluded.
+// is split into tags in Go; release_date derives the decade for the era
+// facet (#1530). Quarantined tracks are excluded.
 func (q *Queries) ListPlayEngagementInputsForUser(ctx context.Context, arg ListPlayEngagementInputsForUserParams) ([]ListPlayEngagementInputsForUserRow, error) {
 	rows, err := q.db.Query(ctx, listPlayEngagementInputsForUser, arg.UserID, arg.Column2)
 	if err != nil {
@@ -176,6 +237,7 @@ func (q *Queries) ListPlayEngagementInputsForUser(ctx context.Context, arg ListP
 			&i.TrackID,
 			&i.ArtistID,
 			&i.Genre,
+			&i.ReleaseDate,
 			&i.Completion,
 			&i.AgeDays,
 		); err != nil {
@@ -228,6 +290,84 @@ func (q *Queries) ListTasteProfileArtistsForUser(ctx context.Context, arg ListTa
 	return items, nil
 }
 
+const listTasteProfileErasForUser = `-- name: ListTasteProfileErasForUser :many
+SELECT era, weight
+FROM taste_profile_eras
+WHERE user_id = $1
+ORDER BY weight DESC
+LIMIT $2
+`
+
+type ListTasteProfileErasForUserParams struct {
+	UserID pgtype.UUID
+	Limit  int32
+}
+
+type ListTasteProfileErasForUserRow struct {
+	Era    string
+	Weight float64
+}
+
+// Top-weighted taste eras (#1530); consumed by the scorer's era term.
+func (q *Queries) ListTasteProfileErasForUser(ctx context.Context, arg ListTasteProfileErasForUserParams) ([]ListTasteProfileErasForUserRow, error) {
+	rows, err := q.db.Query(ctx, listTasteProfileErasForUser, arg.UserID, arg.Limit)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var items []ListTasteProfileErasForUserRow
+	for rows.Next() {
+		var i ListTasteProfileErasForUserRow
+		if err := rows.Scan(&i.Era, &i.Weight); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
+const listTasteProfileMoodsForUser = `-- name: ListTasteProfileMoodsForUser :many
+SELECT mood, weight
+FROM taste_profile_moods
+WHERE user_id = $1
+ORDER BY weight DESC
+LIMIT $2
+`
+
+type ListTasteProfileMoodsForUserParams struct {
+	UserID pgtype.UUID
+	Limit  int32
+}
+
+type ListTasteProfileMoodsForUserRow struct {
+	Mood   string
+	Weight float64
+}
+
+// Top-weighted taste moods (#1534); consumed by the scorer's mood term.
+func (q *Queries) ListTasteProfileMoodsForUser(ctx context.Context, arg ListTasteProfileMoodsForUserParams) ([]ListTasteProfileMoodsForUserRow, error) {
+	rows, err := q.db.Query(ctx, listTasteProfileMoodsForUser, arg.UserID, arg.Limit)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var items []ListTasteProfileMoodsForUserRow
+	for rows.Next() {
+		var i ListTasteProfileMoodsForUserRow
+		if err := rows.Scan(&i.Mood, &i.Weight); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
 const listTasteProfileTagsForUser = `-- name: ListTasteProfileTagsForUser :many
 SELECT tag, weight
 FROM taste_profile_tags

internal/db/dbq/track_tags.sql.go

@@ -110,9 +110,43 @@ func (q *Queries) ListPlayedTrackTagsForUser(ctx context.Context, arg ListPlayed
 	return items, nil
 }
 
+const listTrackTagsForTracks = `-- name: ListTrackTagsForTracks :many
+SELECT tt.track_id, tt.tag
+  FROM track_tags tt
+ WHERE tt.track_id = ANY($1::uuid[])
+`
+
+type ListTrackTagsForTracksRow struct {
+	TrackID pgtype.UUID
+	Tag     string
+}
+
+// Enriched tags for a set of candidate tracks (#1534), so the scorer can
+// derive each candidate's mood buckets at scoring time. One row per (track,
+// tag); the caller filters to mood words via the internal/mood vocabulary.
+func (q *Queries) ListTrackTagsForTracks(ctx context.Context, dollar_1 []pgtype.UUID) ([]ListTrackTagsForTracksRow, error) {
+	rows, err := q.db.Query(ctx, listTrackTagsForTracks, dollar_1)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var items []ListTrackTagsForTracksRow
+	for rows.Next() {
+		var i ListTrackTagsForTracksRow
+		if err := rows.Scan(&i.TrackID, &i.Tag); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
 const listTracksMissingTags = `-- name: ListTracksMissingTags :many
 
-SELECT t.id, t.mbid, t.title, a.name AS artist_name
+SELECT t.id, t.mbid, t.title, a.name AS artist_name, a.mbid AS artist_mbid
   FROM tracks t
   JOIN artists a ON a.id = t.artist_id
  WHERE t.tag_source IS NULL
@@ -131,6 +165,7 @@ type ListTracksMissingTagsRow struct {
 	Mbid       *string
 	Title      string
 	ArtistName string
+	ArtistMbid *string
 }
 
 // Track-tag enrichment queries (milestone #160, #1490). The tag enricher
@@ -140,7 +175,8 @@ type ListTracksMissingTagsRow struct {
 // Tracks eligible for tag enrichment: never processed (tag_source NULL)
 // or previously settled 'none' under an older provider version. Returns
 // the fields the provider chain needs — recording MBID (nullable) for
-// keyed lookups, plus title + artist name for name-based fallback.
+// keyed lookups, title + artist name for name-based fallback, and the
+// artist MBID (nullable) for MusicBrainz's artist-tag fallback (#1519).
 // $1 = current tag_sources_version, $2 = limit.
 func (q *Queries) ListTracksMissingTags(ctx context.Context, arg ListTracksMissingTagsParams) ([]ListTracksMissingTagsRow, error) {
 	rows, err := q.db.Query(ctx, listTracksMissingTags, arg.TagSourcesVersion, arg.Limit)
@@ -156,6 +192,7 @@ func (q *Queries) ListTracksMissingTags(ctx context.Context, arg ListTracksMissi
 			&i.Mbid,
 			&i.Title,
 			&i.ArtistName,
+			&i.ArtistMbid,
 		); err != nil {
 			return nil, err
 		}

internal/db/migrations/0044_taste_tuning_enriched_tag_scale.down.sql

@@ -0,0 +1,2 @@
+-- Reverse 0044_taste_tuning_enriched_tag_scale.up.sql.
+ALTER TABLE taste_tuning DROP COLUMN IF EXISTS enriched_tag_scale;

internal/db/migrations/0044_taste_tuning_enriched_tag_scale.up.sql

@@ -0,0 +1,6 @@
+-- Expose EnrichedTagScale in the tuning lab (#1520). Adds the enriched-tag
+-- weight knob to the taste_tuning singleton so operators can dial how much
+-- folksonomy tags (#1490) count vs raw ID3 genre. DEFAULT 0.5 backfills the
+-- existing row and matches taste.DefaultConfig().EnrichedTagScale.
+ALTER TABLE taste_tuning
+    ADD COLUMN enriched_tag_scale double precision NOT NULL DEFAULT 0.5;

internal/db/migrations/0045_taste_profile_eras.down.sql

@@ -0,0 +1,2 @@
+ALTER TABLE taste_tuning DROP COLUMN IF EXISTS era_scale;
+DROP TABLE IF EXISTS taste_profile_eras;

internal/db/migrations/0045_taste_profile_eras.up.sql

@@ -0,0 +1,26 @@
+-- 0045_taste_profile_eras.up.sql — era/decade taste facet (#1530,
+-- milestone #160 Opt 2). A third taste facet alongside artists + tags:
+-- signed weights over decade buckets ("1990s") derived from
+-- albums.release_date, rebuilt daily by internal/taste next to the
+-- artist/tag facets. Weight is a signed float — positive = drawn to
+-- that era, negative = passively avoided; magnitude reflects decayed
+-- engagement. Consumed by the recommendation scorer's taste match.
+-- Mirrors taste_profile_tags: CASCADE on user delete, indexed by
+-- (user_id, weight DESC) so "top eras" reads stay cheap.
+CREATE TABLE taste_profile_eras (
+    user_id    uuid             NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    era        text             NOT NULL,
+    weight     double precision NOT NULL,
+    updated_at timestamptz      NOT NULL DEFAULT now(),
+    PRIMARY KEY (user_id, era)
+);
+
+CREATE INDEX taste_profile_eras_user_weight_idx
+    ON taste_profile_eras (user_id, weight DESC);
+
+-- Era-facet build knob, tunable in the lab (mirrors enriched_tag_scale,
+-- #1520): scales how strongly a decade-play imprints on the profile.
+-- DEFAULT 0.5 backfills the existing singleton and matches
+-- taste.DefaultConfig().EraScale; 0 disables the era facet entirely.
+ALTER TABLE taste_tuning
+    ADD COLUMN era_scale double precision NOT NULL DEFAULT 0.5;

internal/db/migrations/0046_context_time_weight.down.sql

@@ -0,0 +1 @@
+ALTER TABLE recommendation_weight_profiles DROP COLUMN IF EXISTS context_time_weight;

internal/db/migrations/0046_context_time_weight.up.sql

@@ -0,0 +1,12 @@
+-- 0046_context_time_weight.up.sql — time-of-day/weekday context conditioning
+-- (#1531, milestone #160 Opt 3). Adds a per-profile scoring weight for the new
+-- context-affinity term: how strongly a candidate is boosted when its artist's
+-- play history concentrates in the current daypart × weekday-type cell (in the
+-- user's local timezone). Mirrors the other ScoringWeights columns.
+--
+-- DEFAULT 1.0 backfills both existing profile rows to a modest on-value; the
+-- Go ShippedRadioWeights/ShippedDailyMixWeights carry the same 1.0 so fresh
+-- installs seed identically. Reconcile only seeds MISSING rows (ON CONFLICT DO
+-- NOTHING), so existing rows rely on this DEFAULT until an operator resets.
+ALTER TABLE recommendation_weight_profiles
+    ADD COLUMN context_time_weight double precision NOT NULL DEFAULT 1.0;

internal/db/migrations/0047_taste_profile_moods.down.sql

@@ -0,0 +1,2 @@
+ALTER TABLE taste_tuning DROP COLUMN IF EXISTS mood_scale;
+DROP TABLE IF EXISTS taste_profile_moods;

internal/db/migrations/0047_taste_profile_moods.up.sql

@@ -0,0 +1,25 @@
+-- 0047_taste_profile_moods.up.sql — mood taste facet (#1534, milestone #160
+-- Opt 2b). A fourth taste facet alongside artists + tags + eras: signed weights
+-- over canonical mood buckets (melancholic / energetic / chill / …) derived
+-- from a track's enriched folksonomy tags (#1490) via the internal/mood
+-- vocabulary, rebuilt daily. Weight is a signed float — positive = drawn to
+-- that mood, negative = passively avoided. Coverage is partial (grows with tag
+-- enrichment), so it's a supplement, not a foundation. Mirrors
+-- taste_profile_tags: CASCADE on user delete, indexed by (user_id, weight DESC).
+CREATE TABLE taste_profile_moods (
+    user_id    uuid             NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    mood       text             NOT NULL,
+    weight     double precision NOT NULL,
+    updated_at timestamptz      NOT NULL DEFAULT now(),
+    PRIMARY KEY (user_id, mood)
+);
+
+CREATE INDEX taste_profile_moods_user_weight_idx
+    ON taste_profile_moods (user_id, weight DESC);
+
+-- Mood-facet build knob, tunable in the lab (mirrors era_scale / enriched_tag_
+-- scale): scales how strongly a mood-tagged play imprints on the profile.
+-- DEFAULT 0.5 backfills the existing singleton and matches
+-- taste.DefaultConfig().MoodScale; 0 disables the mood facet entirely.
+ALTER TABLE taste_tuning
+    ADD COLUMN mood_scale double precision NOT NULL DEFAULT 0.5;

internal/db/migrations/0048_play_events_device_class.down.sql

@@ -0,0 +1 @@
+ALTER TABLE play_events DROP COLUMN IF EXISTS device_class;

internal/db/migrations/0048_play_events_device_class.up.sql

@@ -0,0 +1,9 @@
+-- 0048_play_events_device_class.up.sql — device-class context conditioning
+-- (#1551, milestone #160 Opt 3b). Records which class of device a play came
+-- from (mobile / web / …), sent by the client on play-start and normalized
+-- server-side. Extends the #1531 time-of-day/weekday affinity cell to
+-- (daypart × weekday × device) for the radio path. Nullable + no CHECK: values
+-- are normalized in Go (avoids a CHECK-migration each time a client class is
+-- added, rule #36), and historical rows stay NULL → excluded from the device
+-- dimension (a graceful cold-start; the facet ramps as new plays land).
+ALTER TABLE play_events ADD COLUMN device_class text;

internal/db/queries/coplay.sql

@@ -0,0 +1,55 @@
+-- Household co-play similarity (#1533, milestone #160 Opt 5). Minstrel is a
+-- single shared-library, multi-user server (no per-user library ACL), so the
+-- "household" is the whole instance's user set. These queries recompute
+-- artist–artist co-occurrence edges from play_events and store them in
+-- artist_similarity under the pre-provisioned source = 'user_cooccurrence'
+-- (whitelisted in the 0009 CHECK from day one). A periodic worker DELETEs then
+-- re-INSERTs so edges that fall below threshold disappear. Single-user servers
+-- produce no edges (the >= 2 co-player gate), so the arm is empty there.
+
+-- name: DeleteArtistCoplayEdges :exec
+DELETE FROM artist_similarity WHERE source = 'user_cooccurrence';
+
+-- name: InsertArtistCoplayEdges :exec
+-- Two artists are "co-played" when the same users play both. score is the
+-- Jaccard of their distinct-player sets — coplayers / (playersA + playersB −
+-- coplayers) in (0,1] — which controls for globally-popular artists (an artist
+-- everyone plays would otherwise co-occur with everything). Only pairs with
+-- >= 2 distinct co-players AND Jaccard >= $1 (a floor that both prunes weak
+-- edges and self-limits hub artists, whose large denominators drag their
+-- Jaccard down) are kept. Completed plays only, 365-day window.
+WITH user_artists AS (
+    SELECT DISTINCT pe.user_id, t.artist_id
+    FROM play_events pe
+    JOIN tracks t ON t.id = pe.track_id
+    WHERE pe.was_skipped = false
+      AND pe.started_at > now() - interval '365 days'
+),
+artist_players AS (
+    SELECT artist_id, count(*)::float8 AS players
+    FROM user_artists
+    GROUP BY artist_id
+),
+pairs AS (
+    SELECT ua.artist_id AS a_id,
+           ub.artist_id AS b_id,
+           count(*)::float8 AS coplayers
+    FROM user_artists ua
+    JOIN user_artists ub
+      ON ua.user_id = ub.user_id AND ua.artist_id <> ub.artist_id
+    GROUP BY ua.artist_id, ub.artist_id
+    HAVING count(*) >= 2
+),
+scored AS (
+    SELECT p.a_id, p.b_id,
+           p.coplayers / (pa.players + pb.players - p.coplayers) AS score
+    FROM pairs p
+    JOIN artist_players pa ON pa.artist_id = p.a_id
+    JOIN artist_players pb ON pb.artist_id = p.b_id
+)
+INSERT INTO artist_similarity (artist_a_id, artist_b_id, score, source, fetched_at)
+SELECT a_id, b_id, score, 'user_cooccurrence', now()
+FROM scored
+WHERE score >= $1
+ON CONFLICT (artist_a_id, artist_b_id, source)
+DO UPDATE SET score = EXCLUDED.score, fetched_at = EXCLUDED.fetched_at;

internal/db/queries/events.sql

@@ -28,8 +28,10 @@ LIMIT 1;
 -- found (with a stamped kind) in the user's live snapshot for that
 -- variant at ingestion time (#1249, generalized in #1270).
 INSERT INTO play_events (
-    user_id, track_id, session_id, started_at, client_id, source, pick_kind
-) VALUES ($1, $2, $3, $4, $5, $6, sqlc.narg(pick_kind)::text)
+    user_id, track_id, session_id, started_at, client_id, source, pick_kind,
+    device_class
+) VALUES ($1, $2, $3, $4, $5, $6, sqlc.narg(pick_kind)::text,
+    sqlc.narg(device_class)::text)
 RETURNING *;
 
 -- name: GetSystemPickKindForTrack :one

internal/db/queries/recommendation.sql

@@ -10,8 +10,10 @@ SELECT
     (l.user_id IS NOT NULL)::bool AS is_liked,
     pe.last_played_at::timestamptz AS last_played_at,
     pe.play_count,
-    pe.skip_count
+    pe.skip_count,
+    al.release_date AS release_date
 FROM tracks t
+JOIN albums al ON al.id = t.album_id
 LEFT JOIN general_likes l ON l.user_id = $1 AND l.track_id = t.id
 LEFT JOIN LATERAL (
     SELECT
@@ -40,7 +42,9 @@ WHERE t.id <> $2
 --   $10 taste_overlap K (#796 phase 2b — tracks by the user's top
 --   positively-weighted taste-profile artists, so taste-relevant tracks
 --   enter the pool even when the similarity/random arms miss them; scored
---   in Go via TasteMatch, so sim_score here is 0 pool-inclusion).
+--   in Go via TasteMatch, so sim_score here is 0 pool-inclusion),
+--   $11 coplay_artists K (#1533 — tracks by artists co-played across the
+--   instance with the seed's artist; source='user_cooccurrence').
 -- Returns same shape as LoadRadioCandidates plus similarity_score column.
 
 WITH
@@ -124,6 +128,22 @@ taste_overlap AS (
     ORDER BY tpa.weight DESC, t.id
     LIMIT $10
 ),
+coplay_artists AS (
+    -- Household co-play (#1533): tracks by artists co-played across the
+    -- instance with the seed's artist (source='user_cooccurrence', built by
+    -- the coplay worker). Mirrors similar_artists but from local co-occurrence
+    -- instead of ListenBrainz; empty on single-user servers. Same 0.5 damp as
+    -- similar_artists since it's artist-level.
+    SELECT t.id AS track_id, asim.score * 0.5 AS sim_score
+    FROM artist_similarity asim
+    JOIN tracks t ON t.artist_id = asim.artist_b_id
+    JOIN seed_artist sa ON asim.artist_a_id = sa.artist_id
+    WHERE asim.source = 'user_cooccurrence'
+      AND t.id NOT IN (SELECT id FROM excluded_ids)
+      AND t.id <> $2
+    ORDER BY asim.score DESC, random()
+    LIMIT $11
+),
 random_fill AS (
     SELECT t.id AS track_id, 0.0::float8 AS sim_score
     FROM tracks t
@@ -135,6 +155,7 @@ random_fill AS (
           UNION SELECT track_id FROM tag_overlap
           UNION SELECT track_id FROM likes_overlap
           UNION SELECT track_id FROM taste_overlap
+          UNION SELECT track_id FROM coplay_artists
       )
     ORDER BY random()
     LIMIT $9
@@ -145,6 +166,7 @@ SELECT
     pe.last_played_at::timestamptz AS last_played_at,
     pe.play_count,
     pe.skip_count,
+    al.release_date AS release_date,
     COALESCE(max(u.sim_score), 0.0) AS similarity_score
 FROM (
     SELECT track_id, sim_score FROM lb_similar
@@ -152,9 +174,11 @@ FROM (
     UNION ALL SELECT track_id, sim_score FROM tag_overlap
     UNION ALL SELECT track_id, sim_score FROM likes_overlap
     UNION ALL SELECT track_id, sim_score FROM taste_overlap
+    UNION ALL SELECT track_id, sim_score FROM coplay_artists
     UNION ALL SELECT track_id, sim_score FROM random_fill
 ) u
 JOIN tracks t ON t.id = u.track_id
+JOIN albums al ON al.id = t.album_id
 LEFT JOIN general_likes l ON l.user_id = $1 AND l.track_id = t.id
 LEFT JOIN LATERAL (
     SELECT max(started_at) AS last_played_at,
@@ -166,7 +190,72 @@ LEFT JOIN LATERAL (
 GROUP BY t.id, t.title, t.album_id, t.artist_id, t.duration_ms, t.file_path,
          t.file_format, t.file_size, t.bitrate, t.track_number, t.disc_number,
          t.mbid, t.genre, t.added_at, t.updated_at,
-         l.user_id, pe.last_played_at, pe.play_count, pe.skip_count;
+         l.user_id, pe.last_played_at, pe.play_count, pe.skip_count,
+         al.release_date;
+
+-- name: ListArtistContextPlayCountsForUser :many
+-- Per-artist completed-play counts split by whether each play falls in the
+-- CURRENT context cell, in the user's local timezone (#1531). The cell is
+-- daypart × weekday-type, optionally narrowed by device class (#1551): when
+-- $2 (the current device) is '', the device dimension is ignored (identical to
+-- the time-only #1531 behaviour, used by the daily mixes which have no device);
+-- when $2 is set (radio), a play only counts in the cell if its device_class
+-- matches. Feeds the context-affinity scoring term. Skips excluded; a 365-day
+-- window bounds cost. Daypart buckets: night [22,5) morning [5,12)
+-- afternoon [12,17) evening [17,22). Weekend = ISO days 6–7 (Sat/Sun).
+WITH tz AS (
+    SELECT COALESCE(NULLIF(u.timezone, ''), 'UTC') AS zone
+    FROM users u WHERE u.id = $1
+),
+now_cell AS (
+    SELECT
+        CASE
+            WHEN EXTRACT(hour FROM now() AT TIME ZONE tz.zone) < 5  THEN 3
+            WHEN EXTRACT(hour FROM now() AT TIME ZONE tz.zone) < 12 THEN 0
+            WHEN EXTRACT(hour FROM now() AT TIME ZONE tz.zone) < 17 THEN 1
+            WHEN EXTRACT(hour FROM now() AT TIME ZONE tz.zone) < 22 THEN 2
+            ELSE 3
+        END AS daypart,
+        (EXTRACT(isodow FROM now() AT TIME ZONE tz.zone) >= 6) AS is_weekend
+    FROM tz
+),
+plays AS (
+    SELECT t.artist_id,
+           pe.device_class,
+           CASE
+               WHEN EXTRACT(hour FROM pe.started_at AT TIME ZONE tz.zone) < 5  THEN 3
+               WHEN EXTRACT(hour FROM pe.started_at AT TIME ZONE tz.zone) < 12 THEN 0
+               WHEN EXTRACT(hour FROM pe.started_at AT TIME ZONE tz.zone) < 17 THEN 1
+               WHEN EXTRACT(hour FROM pe.started_at AT TIME ZONE tz.zone) < 22 THEN 2
+               ELSE 3
+           END AS daypart,
+           (EXTRACT(isodow FROM pe.started_at AT TIME ZONE tz.zone) >= 6) AS is_weekend
+    FROM play_events pe
+    JOIN tracks t ON t.id = pe.track_id
+    CROSS JOIN tz
+    WHERE pe.user_id = $1
+      AND pe.was_skipped = false
+      AND pe.started_at > now() - interval '365 days'
+)
+SELECT p.artist_id,
+       count(*) AS total_plays,
+       count(*) FILTER (
+           WHERE p.daypart = (SELECT daypart FROM now_cell)
+             AND p.is_weekend = (SELECT is_weekend FROM now_cell)
+             AND ($2::text = '' OR p.device_class = $2::text)
+       ) AS cell_plays
+FROM plays p
+GROUP BY p.artist_id;
+
+-- name: GetLatestPlayDeviceClassForUser :one
+-- The device_class of the user's most recent play (#1551), used as the
+-- "current device" for radio context conditioning. NULL when the latest play
+-- predates device capture or came from a client that didn't send one.
+SELECT device_class
+FROM play_events
+WHERE user_id = $1
+ORDER BY started_at DESC
+LIMIT 1;
 
 -- name: SuggestArtistsForUser :many
 -- M5c: per-user artist suggestions ranked by signal x similarity. The

internal/db/queries/recommendation_tuning.sql

@@ -6,8 +6,9 @@
 -- doesn't exist yet. Never overwrites operator-tuned values.
 INSERT INTO recommendation_weight_profiles (
     profile, base_weight, like_boost, recency_weight, skip_penalty,
-    jitter_magnitude, context_weight, similarity_weight, taste_weight
-) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
+    jitter_magnitude, context_weight, similarity_weight, taste_weight,
+    context_time_weight
+) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)
 ON CONFLICT (profile) DO NOTHING;
 
 -- name: ListWeightProfiles :many
@@ -15,23 +16,25 @@ SELECT * FROM recommendation_weight_profiles ORDER BY profile;
 
 -- name: UpdateWeightProfile :one
 UPDATE recommendation_weight_profiles
-   SET base_weight       = $2,
-       like_boost        = $3,
-       recency_weight    = $4,
-       skip_penalty      = $5,
-       jitter_magnitude  = $6,
-       context_weight    = $7,
-       similarity_weight = $8,
-       taste_weight      = $9,
-       updated_at        = now()
+   SET base_weight         = $2,
+       like_boost          = $3,
+       recency_weight      = $4,
+       skip_penalty        = $5,
+       jitter_magnitude    = $6,
+       context_weight      = $7,
+       similarity_weight   = $8,
+       taste_weight        = $9,
+       context_time_weight = $10,
+       updated_at          = now()
  WHERE profile = $1
 RETURNING *;
 
 -- name: UpsertTasteTuningDefaults :exec
 INSERT INTO taste_tuning (
     singleton, half_life_days, engagement_hard_skip,
-    engagement_neutral, engagement_full
-) VALUES (true, $1, $2, $3, $4)
+    engagement_neutral, engagement_full, enriched_tag_scale, era_scale,
+    mood_scale
+) VALUES (true, $1, $2, $3, $4, $5, $6, $7)
 ON CONFLICT (singleton) DO NOTHING;
 
 -- name: GetTasteTuning :one
@@ -43,6 +46,9 @@ UPDATE taste_tuning
        engagement_hard_skip = $2,
        engagement_neutral   = $3,
        engagement_full      = $4,
+       enriched_tag_scale   = $5,
+       era_scale            = $6,
+       mood_scale           = $7,
        updated_at           = now()
  WHERE singleton = true
 RETURNING *;

internal/db/queries/taste_profile.sql

@@ -6,11 +6,13 @@
 -- One row per play in the decay-relevant window. completion is the play's
 -- completion ratio (precomputed column when present, else duration_played /
 -- track duration, clamped to [0,1]); age_days drives the time-decay. Genre
--- is split into tags in Go. Quarantined tracks are excluded.
+-- is split into tags in Go; release_date derives the decade for the era
+-- facet (#1530). Quarantined tracks are excluded.
 SELECT
     t.id AS track_id,
     t.artist_id,
     t.genre,
+    a.release_date,
     LEAST(GREATEST(
         COALESCE(pe.completion_ratio,
                  pe.duration_played_ms::float8 / NULLIF(t.duration_ms, 0),
@@ -18,6 +20,7 @@ SELECT
     (EXTRACT(epoch FROM now() - pe.started_at) / 86400.0)::float8 AS age_days
 FROM play_events pe
 JOIN tracks t ON t.id = pe.track_id
+JOIN albums a ON a.id = t.album_id
 WHERE pe.user_id = $1
   AND pe.started_at > now() - ($2::float8 * INTERVAL '1 day')
   AND NOT EXISTS (
@@ -26,12 +29,13 @@ WHERE pe.user_id = $1
   );
 
 -- name: ListLikedTrackTasteInputsForUser :many
--- (track_id, artist_id, genre) for each track the user has explicitly
--- liked. Feeds the track-like bonus into the liked track's artist and
--- tags; track_id keys the enriched track_tags lookup (#1490).
-SELECT t.id AS track_id, t.artist_id, t.genre
+-- (track_id, artist_id, genre, release_date) for each track the user has
+-- explicitly liked. Feeds the track-like bonus into the liked track's artist,
+-- tags, and era (#1530); track_id keys the enriched track_tags lookup (#1490).
+SELECT t.id AS track_id, t.artist_id, t.genre, a.release_date
 FROM general_likes gl
 JOIN tracks t ON t.id = gl.track_id
+JOIN albums a ON a.id = t.album_id
 WHERE gl.user_id = $1;
 
 -- name: ListLikedArtistIDsForUser :many
@@ -66,3 +70,33 @@ FROM taste_profile_tags
 WHERE user_id = $1
 ORDER BY weight DESC
 LIMIT $2;
+
+-- name: DeleteTasteProfileErasForUser :exec
+DELETE FROM taste_profile_eras WHERE user_id = $1;
+
+-- name: InsertTasteProfileEra :exec
+INSERT INTO taste_profile_eras (user_id, era, weight)
+VALUES ($1, $2, $3);
+
+-- name: ListTasteProfileErasForUser :many
+-- Top-weighted taste eras (#1530); consumed by the scorer's era term.
+SELECT era, weight
+FROM taste_profile_eras
+WHERE user_id = $1
+ORDER BY weight DESC
+LIMIT $2;
+
+-- name: DeleteTasteProfileMoodsForUser :exec
+DELETE FROM taste_profile_moods WHERE user_id = $1;
+
+-- name: InsertTasteProfileMood :exec
+INSERT INTO taste_profile_moods (user_id, mood, weight)
+VALUES ($1, $2, $3);
+
+-- name: ListTasteProfileMoodsForUser :many
+-- Top-weighted taste moods (#1534); consumed by the scorer's mood term.
+SELECT mood, weight
+FROM taste_profile_moods
+WHERE user_id = $1
+ORDER BY weight DESC
+LIMIT $2;

internal/db/queries/track_tags.sql

@@ -7,9 +7,10 @@
 -- Tracks eligible for tag enrichment: never processed (tag_source NULL)
 -- or previously settled 'none' under an older provider version. Returns
 -- the fields the provider chain needs — recording MBID (nullable) for
--- keyed lookups, plus title + artist name for name-based fallback.
+-- keyed lookups, title + artist name for name-based fallback, and the
+-- artist MBID (nullable) for MusicBrainz's artist-tag fallback (#1519).
 -- $1 = current tag_sources_version, $2 = limit.
-SELECT t.id, t.mbid, t.title, a.name AS artist_name
+SELECT t.id, t.mbid, t.title, a.name AS artist_name, a.mbid AS artist_mbid
   FROM tracks t
   JOIN artists a ON a.id = t.artist_id
  WHERE t.tag_source IS NULL
@@ -55,3 +56,11 @@ SELECT tt.track_id, tt.tag, tt.weight
   FROM track_tags tt
   JOIN general_likes gl ON gl.track_id = tt.track_id
  WHERE gl.user_id = $1;
+
+-- name: ListTrackTagsForTracks :many
+-- Enriched tags for a set of candidate tracks (#1534), so the scorer can
+-- derive each candidate's mood buckets at scoring time. One row per (track,
+-- tag); the caller filters to mood words via the internal/mood vocabulary.
+SELECT tt.track_id, tt.tag
+  FROM track_tags tt
+ WHERE tt.track_id = ANY($1::uuid[]);

internal/mood/mood.go

@@ -0,0 +1,58 @@
+// Package mood maps folksonomy tags (from the track_tags cache, #1490) to a
+// small set of canonical mood buckets (#1534, milestone #160 Opt 2b). Both the
+// taste-profile builder and the recommendation scorer classify a track's tags
+// through Of() so a track's mood is derived the same way on both sides.
+//
+// The vocabulary is intentionally narrow: only words that clearly denote mood
+// (not genre). A track with no mood-word tags contributes nothing — the mood
+// facet is a supplement whose coverage grows with folksonomy enrichment
+// (thin on MusicBrainz-only, richer once Last.fm is keyed).
+package mood
+
+import "strings"
+
+// vocab maps a lowercased folksonomy tag to its canonical mood bucket. Several
+// synonyms collapse to one bucket so "sad" / "melancholy" / "melancholic" all
+// score the same dimension.
+var vocab = map[string]string{
+	// melancholic
+	"melancholic": "melancholic", "melancholy": "melancholic", "sad": "melancholic",
+	"sombre": "melancholic", "somber": "melancholic", "wistful": "melancholic",
+	"bittersweet": "melancholic", "mournful": "melancholic",
+	// energetic
+	"energetic": "energetic", "energy": "energetic", "upbeat": "energetic",
+	"uplifting": "energetic", "party": "energetic", "anthemic": "energetic",
+	// chill
+	"chill": "chill", "chillout": "chill", "chilled": "chill", "mellow": "chill",
+	"relaxing": "chill", "relaxed": "chill", "calm": "chill", "laid-back": "chill",
+	"laidback": "chill", "soothing": "chill",
+	// aggressive
+	"aggressive": "aggressive", "angry": "aggressive", "intense": "aggressive",
+	"heavy": "aggressive", "brutal": "aggressive",
+	// dark
+	"dark": "dark", "moody": "dark", "brooding": "dark", "haunting": "dark", "eerie": "dark",
+	// dreamy
+	"dreamy": "dreamy", "ethereal": "dreamy", "atmospheric": "dreamy",
+	"ambient": "dreamy", "hypnotic": "dreamy",
+	// happy
+	"happy": "happy", "cheerful": "happy", "feel good": "happy", "feel-good": "happy",
+	"feelgood": "happy", "joyful": "happy", "fun": "happy",
+	// romantic
+	"romantic": "romantic", "sensual": "romantic", "sexy": "romantic", "sentimental": "romantic",
+}
+
+// Of returns the distinct canonical mood buckets present in tags, lowercasing +
+// trimming each tag before lookup. Returns nil when no tag maps to a mood, so
+// callers get no mood signal for a track with only genre/descriptive tags.
+func Of(tags []string) []string {
+	var out []string
+	seen := make(map[string]bool)
+	for _, t := range tags {
+		key := strings.ToLower(strings.TrimSpace(t))
+		if m, ok := vocab[key]; ok && !seen[m] {
+			seen[m] = true
+			out = append(out, m)
+		}
+	}
+	return out
+}

internal/mood/mood_test.go

@@ -0,0 +1,43 @@
+package mood
+
+import (
+	"sort"
+	"testing"
+)
+
+func TestOf(t *testing.T) {
+	cases := []struct {
+		name string
+		in   []string
+		want []string
+	}{
+		{"synonyms collapse", []string{"sad", "melancholy", "melancholic"}, []string{"melancholic"}},
+		{"case + whitespace", []string{" CHILL ", "Mellow"}, []string{"chill"}},
+		{"multiple buckets", []string{"energetic", "dark"}, []string{"dark", "energetic"}},
+		{"genre-only → none", []string{"rock", "shoegaze", "post-punk"}, nil},
+		{"empty", nil, nil},
+	}
+	for _, c := range cases {
+		got := Of(c.in)
+		sort.Strings(got)
+		want := append([]string(nil), c.want...)
+		sort.Strings(want)
+		if len(got) != len(want) {
+			t.Errorf("%s: Of(%v) = %v, want %v", c.name, c.in, got, want)
+			continue
+		}
+		for i := range got {
+			if got[i] != want[i] {
+				t.Errorf("%s: Of(%v) = %v, want %v", c.name, c.in, got, want)
+				break
+			}
+		}
+	}
+}
+
+func TestOf_Dedupes(t *testing.T) {
+	// Three tags mapping to the same bucket yield one entry.
+	if got := Of([]string{"chill", "mellow", "relaxed"}); len(got) != 1 || got[0] != "chill" {
+		t.Errorf("Of dedupe = %v, want [chill]", got)
+	}
+}

internal/playevents/writer.go

@@ -65,7 +65,16 @@ func (w *Writer) RecordPlayStarted(
 	clientID string,
 	at time.Time,
 ) (StartedResult, error) {
-	return w.RecordPlayStartedWithSource(ctx, userID, trackID, clientID, "", at)
+	return w.RecordPlayStartedWithSource(ctx, userID, trackID, clientID, "", "", at)
+}
+
+// strPtrOrNil maps an empty string to a NULL text column (nullable pointer),
+// mirroring the clientID/source nil-on-empty pattern used above.
+func strPtrOrNil(s string) *string {
+	if s == "" {
+		return nil
+	}
+	return &s
 }
 
 // systemPlaylistSources are the play_events.source values that count
@@ -136,7 +145,7 @@ func lookupSystemPickKind(
 func (w *Writer) RecordPlayStartedWithSource(
 	ctx context.Context,
 	userID, trackID pgtype.UUID,
-	clientID, source string,
+	clientID, source, deviceClass string,
 	at time.Time,
 ) (StartedResult, error) {
 	var out StartedResult
@@ -165,13 +174,14 @@ func (w *Writer) RecordPlayStartedWithSource(
 			}
 		}
 		ev, err := q.InsertPlayEvent(ctx, dbq.InsertPlayEventParams{
-			UserID:    userID,
-			TrackID:   trackID,
-			SessionID: sessionID,
-			StartedAt: pgtype.Timestamptz{Time: at, Valid: true},
-			ClientID:  clientIDPtr,
-			Source:    sourcePtr,
-			PickKind:  pickKind,
+			UserID:      userID,
+			TrackID:     trackID,
+			SessionID:   sessionID,
+			StartedAt:   pgtype.Timestamptz{Time: at, Valid: true},
+			ClientID:    clientIDPtr,
+			Source:      sourcePtr,
+			PickKind:    pickKind,
+			DeviceClass: strPtrOrNil(deviceClass),
 		})
 		if err != nil {
 			return err
@@ -389,7 +399,7 @@ func (w *Writer) RecordSyntheticCompletedPlay(
 func (w *Writer) RecordOfflinePlay(
 	ctx context.Context,
 	userID, trackID pgtype.UUID,
-	clientID, source string,
+	clientID, source, deviceClass string,
 	at time.Time,
 	durationPlayedMs int32,
 ) error {
@@ -441,13 +451,14 @@ func (w *Writer) RecordOfflinePlay(
 			}
 		}
 		ev, err := q.InsertPlayEvent(ctx, dbq.InsertPlayEventParams{
-			UserID:    userID,
-			TrackID:   trackID,
-			SessionID: sessionID,
-			StartedAt: pgtype.Timestamptz{Time: at, Valid: true},
-			ClientID:  clientIDPtr,
-			Source:    sourcePtr,
-			PickKind:  pickKind,
+			UserID:      userID,
+			TrackID:     trackID,
+			SessionID:   sessionID,
+			StartedAt:   pgtype.Timestamptz{Time: at, Valid: true},
+			ClientID:    clientIDPtr,
+			Source:      sourcePtr,
+			PickKind:    pickKind,
+			DeviceClass: strPtrOrNil(deviceClass),
 		})
 		if err != nil {
 			return err

internal/playevents/writer_test.go

@@ -226,10 +226,10 @@ func TestRecordOfflinePlay_DedupsByUserTrackStartedAt(t *testing.T) {
 	f := newFixture(t, 200_000)
 	ctx := context.Background()
 	at := time.Now().UTC()
-	if err := f.w.RecordOfflinePlay(ctx, f.user, f.track, "c", "", at, 120_000); err != nil {
+	if err := f.w.RecordOfflinePlay(ctx, f.user, f.track, "c", "", "", at, 120_000); err != nil {
 		t.Fatalf("first offline: %v", err)
 	}
-	if err := f.w.RecordOfflinePlay(ctx, f.user, f.track, "c", "", at, 120_000); err != nil {
+	if err := f.w.RecordOfflinePlay(ctx, f.user, f.track, "c", "", "", at, 120_000); err != nil {
 		t.Fatalf("replay offline: %v", err)
 	}
 	var count int
@@ -444,7 +444,7 @@ func TestRecordPlayStartedWithSource_AppendsRotation(t *testing.T) {
 	f := newFixture(t, 200_000)
 	now := time.Now().UTC()
 	if _, err := f.w.RecordPlayStartedWithSource(
-		context.Background(), f.user, f.track, "c", "for_you", now,
+		context.Background(), f.user, f.track, "c", "for_you", "", now,
 	); err != nil {
 		t.Fatalf("RecordPlayStartedWithSource: %v", err)
 	}
@@ -460,7 +460,7 @@ func TestRecordPlayStartedWithSource_AppendsRotation(t *testing.T) {
 
 	// Re-playing the same track stays a set (no duplicate append).
 	if _, err := f.w.RecordPlayStartedWithSource(
-		context.Background(), f.user, f.track, "c", "for_you", now.Add(time.Minute),
+		context.Background(), f.user, f.track, "c", "for_you", "", now.Add(time.Minute),
 	); err != nil {
 		t.Fatalf("RecordPlayStartedWithSource 2: %v", err)
 	}
@@ -511,7 +511,7 @@ func TestRecordPlayStartedWithSource_StampsForYouPickKind(t *testing.T) {
 	f := newFixture(t, 200_000)
 	seedSystemSnapshot(t, f, "for_you", "fresh")
 	res, err := f.w.RecordPlayStartedWithSource(
-		context.Background(), f.user, f.track, "c", "for_you", time.Now().UTC(),
+		context.Background(), f.user, f.track, "c", "for_you", "", time.Now().UTC(),
 	)
 	if err != nil {
 		t.Fatalf("RecordPlayStartedWithSource: %v", err)
@@ -530,7 +530,7 @@ func TestRecordPlayStartedWithSource_NoSnapshotMatch_PickKindNull(t *testing.T)
 	// out, or no snapshot exists) stays unattributed rather than guessing.
 	f := newFixture(t, 200_000)
 	res, err := f.w.RecordPlayStartedWithSource(
-		context.Background(), f.user, f.track, "c", "for_you", time.Now().UTC(),
+		context.Background(), f.user, f.track, "c", "for_you", "", time.Now().UTC(),
 	)
 	if err != nil {
 		t.Fatalf("RecordPlayStartedWithSource: %v", err)
@@ -552,7 +552,7 @@ func TestRecordPlayStartedWithSource_CrossVariant_PickKindNull(t *testing.T) {
 	f := newFixture(t, 200_000)
 	seedSystemSnapshot(t, f, "for_you", "taste")
 	res, err := f.w.RecordPlayStartedWithSource(
-		context.Background(), f.user, f.track, "c", "discover", time.Now().UTC(),
+		context.Background(), f.user, f.track, "c", "discover", "", time.Now().UTC(),
 	)
 	if err != nil {
 		t.Fatalf("RecordPlayStartedWithSource: %v", err)
@@ -572,7 +572,7 @@ func TestRecordPlayStartedWithSource_StampsDiscoverBucket(t *testing.T) {
 	f := newFixture(t, 200_000)
 	seedSystemSnapshot(t, f, "discover", "dormant")
 	res, err := f.w.RecordPlayStartedWithSource(
-		context.Background(), f.user, f.track, "c", "discover", time.Now().UTC(),
+		context.Background(), f.user, f.track, "c", "discover", "", time.Now().UTC(),
 	)
 	if err != nil {
 		t.Fatalf("RecordPlayStartedWithSource: %v", err)
@@ -593,7 +593,7 @@ func TestRecordOfflinePlay_StampsForYouPickKind(t *testing.T) {
 	seedSystemSnapshot(t, f, "for_you", "taste")
 	at := time.Now().UTC().Add(-time.Hour)
 	if err := f.w.RecordOfflinePlay(
-		context.Background(), f.user, f.track, "c", "for_you", at, 180_000,
+		context.Background(), f.user, f.track, "c", "for_you", "", at, 180_000,
 	); err != nil {
 		t.Fatalf("RecordOfflinePlay: %v", err)
 	}

internal/playlists/system.go

@@ -215,6 +215,9 @@ var (
 		// [-1,+1], so 1.5 makes a strong taste fit comparable to a like boost
 		// while passive avoidance (negative) gently demotes.
 		TasteWeight: 1.5,
+		// Time-of-day/weekday context affinity (#1531), in [-1,+1]. Starts
+		// uniform with radio pending trend data.
+		ContextTimeWeight: 1.0,
 	}
 	systemTasteConfig = taste.DefaultConfig()
 )
@@ -543,6 +546,9 @@ func systemForYouSourceLimits() recommendation.CandidateSourceLimits {
 		// deep slice of the user's top taste-profile artists into the pool
 		// (#796 phase 2b). Empty for cold-start users (no profile yet).
 		TasteOverlap: 80,
+		// Household co-play (#1533): a deeper collaborative slice for the
+		// taste surfaces. Empty on single-user servers.
+		UserCoplay: 40,
 	}
 }
 

internal/recommendation/candidates.go

@@ -8,6 +8,7 @@ import (
 	"github.com/jackc/pgx/v5/pgtype"
 
 	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/mood"
 )
 
 // LoadCandidates fetches the candidate pool for radio scoring. Combines
@@ -41,6 +42,11 @@ func LoadCandidates(
 		return nil, err
 	}
 
+	affinity, err := LoadContextAffinity(ctx, q, userID, currentVector.DeviceClass)
+	if err != nil {
+		return nil, err
+	}
+
 	out := make([]Candidate, 0, len(rows))
 	for _, r := range rows {
 		var lpt *time.Time
@@ -57,7 +63,11 @@ func LoadCandidates(
 				PlayCount:            int(r.PlayCount),
 				SkipCount:            int(r.SkipCount),
 				ContextualMatchScore: ctxScore,
-				TasteMatchScore:      profile.Match(r.Track.ArtistID, r.Track.Genre),
+				// Fallback path: mood is scored only in the primary
+				// (similarity) loader — loading per-candidate tags over this
+				// near-whole-library pool isn't worth it (nil moods → 0).
+				TasteMatchScore:      profile.Match(r.Track.ArtistID, r.Track.Genre, r.ReleaseDate, nil),
+				ContextAffinityScore: affinity.Affinity(r.Track.ArtistID),
 			},
 		})
 	}
@@ -76,6 +86,10 @@ type CandidateSourceLimits struct {
 	// weighted taste-profile artists. 0 disables the arm (e.g. cold-start
 	// users have an empty profile, so it contributes nothing anyway).
 	TasteOverlap int
+	// UserCoplay (#1533): tracks by artists co-played across the instance
+	// with the seed's artist (source='user_cooccurrence'). Empty on
+	// single-user servers, so it contributes nothing there.
+	UserCoplay int
 }
 
 // DefaultCandidateSourceLimits returns the v1 hardcoded constants per spec.
@@ -87,6 +101,7 @@ func DefaultCandidateSourceLimits() CandidateSourceLimits {
 		LikesOverlap:  20,
 		RandomFill:    30,
 		TasteOverlap:  20,
+		UserCoplay:    20,
 	}
 }
 
@@ -119,6 +134,7 @@ func LoadCandidatesFromSimilarity(
 		Limit_4: int32(limits.LikesOverlap),
 		Limit_5: int32(limits.RandomFill),
 		Limit_6: int32(limits.TasteOverlap),
+		Limit_7: int32(limits.UserCoplay),
 	})
 	if err != nil {
 		return nil, err
@@ -134,6 +150,20 @@ func LoadCandidatesFromSimilarity(
 		return nil, err
 	}
 
+	affinity, err := LoadContextAffinity(ctx, q, userID, currentVector.DeviceClass)
+	if err != nil {
+		return nil, err
+	}
+
+	trackIDs := make([]pgtype.UUID, 0, len(rows))
+	for _, r := range rows {
+		trackIDs = append(trackIDs, r.Track.ID)
+	}
+	moods, err := loadCandidateMoods(ctx, q, trackIDs)
+	if err != nil {
+		return nil, err
+	}
+
 	out := make([]Candidate, 0, len(rows))
 	for _, r := range rows {
 		var lpt *time.Time
@@ -158,13 +188,42 @@ func LoadCandidatesFromSimilarity(
 				SkipCount:            int(r.SkipCount),
 				ContextualMatchScore: ctxScore,
 				SimilarityScore:      simScore,
-				TasteMatchScore:      profile.Match(r.Track.ArtistID, r.Track.Genre),
+				TasteMatchScore: profile.Match(
+					r.Track.ArtistID, r.Track.Genre, r.ReleaseDate, moods[r.Track.ID]),
+				ContextAffinityScore: affinity.Affinity(r.Track.ArtistID),
 			},
 		})
 	}
 	return out, nil
 }
 
+// loadCandidateMoods fetches the enriched tags for the given candidate tracks
+// and reduces each to its canonical mood buckets (internal/mood, #1534), so the
+// scorer can apply the mood facet per candidate. Tracks with no mood-word tags
+// are absent from the map (→ no mood signal). Empty input short-circuits.
+func loadCandidateMoods(
+	ctx context.Context, q *dbq.Queries, trackIDs []pgtype.UUID,
+) (map[pgtype.UUID][]string, error) {
+	if len(trackIDs) == 0 {
+		return map[pgtype.UUID][]string{}, nil
+	}
+	rows, err := q.ListTrackTagsForTracks(ctx, trackIDs)
+	if err != nil {
+		return nil, err
+	}
+	tagsByTrack := make(map[pgtype.UUID][]string)
+	for _, r := range rows {
+		tagsByTrack[r.TrackID] = append(tagsByTrack[r.TrackID], r.Tag)
+	}
+	out := make(map[pgtype.UUID][]string, len(tagsByTrack))
+	for id, tags := range tagsByTrack {
+		if m := mood.Of(tags); len(m) > 0 {
+			out[id] = m
+		}
+	}
+	return out, nil
+}
+
 // loadContextualLikesByTrack fetches the user's active contextual_likes in
 // one query and groups them by track_id. Rows whose session_vector fails
 // to unmarshal are skipped with no error (don't poison scoring over one

internal/recommendation/context.go

@@ -0,0 +1,75 @@
+package recommendation
+
+import (
+	"context"
+
+	"github.com/jackc/pgx/v5/pgtype"
+
+	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
+)
+
+// contextAffinityShrinkage is the pseudo-count that pulls a low-play artist's
+// cell-share toward the user's baseline, so an artist with one or two plays
+// can't swing its affinity to ±1 on noise. At k plays the estimate sits
+// halfway between the raw cell-share and the baseline.
+const contextAffinityShrinkage = 5.0
+
+// ContextAffinity is the read-side map of per-artist time-of-day/weekday
+// affinity for the CURRENT context (#1531): artist_id → score in [-1, +1].
+// Absent artists (no play history) score 0, so cold-start candidates stay
+// neutral. The zero value is a valid all-neutral affinity.
+type ContextAffinity struct {
+	byArtist map[pgtype.UUID]float64
+}
+
+// Affinity returns the artist's current-context affinity, or 0 if unknown.
+func (c ContextAffinity) Affinity(artistID pgtype.UUID) float64 {
+	return c.byArtist[artistID]
+}
+
+// LoadContextAffinity computes each artist's affinity for the user's CURRENT
+// context cell — daypart × weekday, narrowed by deviceClass when non-empty
+// (#1551; radio passes the current device, the daily mixes pass "" for a
+// device-agnostic cell). For every artist with completed plays in the window it
+// compares the share of that artist's plays that fall in the current cell
+// against the user's overall baseline share, shrinking sparse artists toward
+// the baseline. Returns an empty (all-neutral) affinity when the user has no
+// plays.
+func LoadContextAffinity(
+	ctx context.Context, q *dbq.Queries, userID pgtype.UUID, deviceClass string,
+) (ContextAffinity, error) {
+	rows, err := q.ListArtistContextPlayCountsForUser(ctx, dbq.ListArtistContextPlayCountsForUserParams{
+		ID:      userID,
+		Column2: deviceClass,
+	})
+	if err != nil {
+		return ContextAffinity{}, err
+	}
+	var totalPlays, cellPlays int64
+	for _, r := range rows {
+		totalPlays += r.TotalPlays
+		cellPlays += r.CellPlays
+	}
+	out := ContextAffinity{byArtist: make(map[pgtype.UUID]float64, len(rows))}
+	if totalPlays == 0 {
+		return out, nil
+	}
+	baseline := float64(cellPlays) / float64(totalPlays)
+	for _, r := range rows {
+		out.byArtist[r.ArtistID] = contextAffinity(
+			float64(r.CellPlays), float64(r.TotalPlays), baseline, contextAffinityShrinkage)
+	}
+	return out, nil
+}
+
+// contextAffinity returns an artist's shrunk cell-share minus the user's
+// baseline share, clamped to [-1, 1]. The shrinkage pseudo-count k pulls
+// low-play artists toward the baseline (→ 0 affinity) so noise can't dominate;
+// a heavily-played artist keeps close to its raw over/under-representation.
+func contextAffinity(cellPlays, totalPlays, baseline, k float64) float64 {
+	if totalPlays == 0 {
+		return 0
+	}
+	shrunk := (cellPlays + baseline*k) / (totalPlays + k)
+	return clampUnit(shrunk - baseline)
+}

internal/recommendation/context_device_integration_test.go

@@ -0,0 +1,87 @@
+package recommendation
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/jackc/pgx/v5/pgtype"
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
+)
+
+func insertPlayEventDevice(
+	t *testing.T, pool *pgxpool.Pool, userID, trackID pgtype.UUID, startedAt time.Time, device string,
+) {
+	t.Helper()
+	ctx := context.Background()
+	var sessionID pgtype.UUID
+	if err := pool.QueryRow(ctx,
+		`INSERT INTO play_sessions (user_id, started_at, last_event_at, client_id)
+		 VALUES ($1, $2, $2, 'ctx-dev-test') RETURNING id`,
+		userID, startedAt).Scan(&sessionID); err != nil {
+		t.Fatalf("insert play_session: %v", err)
+	}
+	if _, err := pool.Exec(ctx,
+		`INSERT INTO play_events (user_id, track_id, session_id, started_at, was_skipped, device_class)
+		 VALUES ($1, $2, $3, $4, false, $5)`,
+		userID, trackID, sessionID, startedAt, device); err != nil {
+		t.Fatalf("insert play_event: %v", err)
+	}
+}
+
+// TestLoadContextAffinity_DeviceNarrowing seeds one artist played only on
+// mobile and another only on web (all in the current time cell), and verifies
+// the current-device parameter narrows the affinity cell (#1551): on 'mobile'
+// the mobile artist out-scores the web artist and vice-versa, while the
+// device-agnostic (”) pass treats them equally.
+func TestLoadContextAffinity_DeviceNarrowing(t *testing.T) {
+	pool := newPool(t)
+	ctx := context.Background()
+	q := dbq.New(pool)
+
+	u := seedUser(t, pool, "ctx-dev")
+	aMobile := seedArtist(t, pool, "MobileArtist", "")
+	aWeb := seedArtist(t, pool, "WebArtist", "")
+	alM := seedAlbumForArtist(t, pool, aMobile.ID, "AlbM")
+	tM := seedTrackOnAlbum(t, pool, alM.ID, aMobile.ID, "TrkM")
+	alW := seedAlbumForArtist(t, pool, aWeb.ID, "AlbW")
+	tW := seedTrackOnAlbum(t, pool, alW.ID, aWeb.ID, "TrkW")
+
+	now := time.Now()
+	for i := 0; i < 5; i++ {
+		insertPlayEventDevice(t, pool, u.ID, tM.ID, now, "mobile")
+		insertPlayEventDevice(t, pool, u.ID, tW.ID, now, "web")
+	}
+
+	mob, err := LoadContextAffinity(ctx, q, u.ID, "mobile")
+	if err != nil {
+		t.Fatalf("mobile: %v", err)
+	}
+	if mob.Affinity(aMobile.ID) <= mob.Affinity(aWeb.ID) {
+		t.Errorf("on mobile, mobile artist (%.3f) should out-score web artist (%.3f)",
+			mob.Affinity(aMobile.ID), mob.Affinity(aWeb.ID))
+	}
+
+	web, err := LoadContextAffinity(ctx, q, u.ID, "web")
+	if err != nil {
+		t.Fatalf("web: %v", err)
+	}
+	if web.Affinity(aWeb.ID) <= web.Affinity(aMobile.ID) {
+		t.Errorf("on web, web artist (%.3f) should out-score mobile artist (%.3f)",
+			web.Affinity(aWeb.ID), web.Affinity(aMobile.ID))
+	}
+
+	// Device-agnostic ('' ): all plays fall in the same time cell, so the two
+	// artists are treated identically — the device dimension is what separates
+	// them above.
+	agn, err := LoadContextAffinity(ctx, q, u.ID, "")
+	if err != nil {
+		t.Fatalf("agnostic: %v", err)
+	}
+	if agn.Affinity(aMobile.ID) != agn.Affinity(aWeb.ID) {
+		t.Errorf("device-agnostic affinities should match, got mobile=%.3f web=%.3f",
+			agn.Affinity(aMobile.ID), agn.Affinity(aWeb.ID))
+	}
+}

internal/recommendation/context_test.go

@@ -0,0 +1,57 @@
+package recommendation
+
+import (
+	"testing"
+	"time"
+)
+
+func TestContextAffinity(t *testing.T) {
+	const baseline = 0.4 // 40% of the user's plays fall in the current cell
+	const k = contextAffinityShrinkage
+
+	// Heavy history, over-represented in the current cell → positive.
+	if a := contextAffinity(80, 100, baseline, k); a <= 0 {
+		t.Errorf("over-represented artist affinity = %.3f, want positive", a)
+	}
+	// Heavy history, under-represented → negative.
+	if a := contextAffinity(10, 100, baseline, k); a >= 0 {
+		t.Errorf("under-represented artist affinity = %.3f, want negative", a)
+	}
+	// A sparse artist (1/1) shrinks toward the baseline, so its affinity is
+	// smaller than a heavily-played artist with the same raw cell-share.
+	sparse := contextAffinity(1, 1, baseline, k)
+	heavy := contextAffinity(100, 100, baseline, k)
+	if sparse >= heavy {
+		t.Errorf("sparse (%.3f) should shrink below heavy (%.3f)", sparse, heavy)
+	}
+	// No plays → neutral.
+	if a := contextAffinity(0, 0, baseline, k); a != 0 {
+		t.Errorf("no plays affinity = %.3f, want 0", a)
+	}
+	// Result stays within [-1, 1].
+	for _, tc := range [][2]float64{{100, 100}, {0, 100}, {50, 50}} {
+		a := contextAffinity(tc[0], tc[1], baseline, k)
+		if a < -1 || a > 1 {
+			t.Errorf("affinity out of [-1,1]: %.3f", a)
+		}
+	}
+}
+
+func TestScore_ContextTermAddsAndSubtracts(t *testing.T) {
+	now := time.Now()
+	zeroJitter := func() float64 { return 0.5 } // (0.5*2-1)=0 with any magnitude
+	w := ScoringWeights{ContextTimeWeight: 2.0} // all other weights 0
+
+	pos := Score(ScoringInputs{ContextAffinityScore: 1.0}, w, now, zeroJitter)
+	if !almostEq(pos, 2.0) {
+		t.Errorf("positive context affinity: Score = %.3f, want 2.0", pos)
+	}
+	neg := Score(ScoringInputs{ContextAffinityScore: -1.0}, w, now, zeroJitter)
+	if !almostEq(neg, -2.0) {
+		t.Errorf("negative context affinity: Score = %.3f, want -2.0 (demotes)", neg)
+	}
+	off := Score(ScoringInputs{ContextAffinityScore: 1.0}, ScoringWeights{}, now, zeroJitter)
+	if !almostEq(off, 0.0) {
+		t.Errorf("ContextTimeWeight 0: Score = %.3f, want 0 (no effect)", off)
+	}
+}

internal/recommendation/score.go

@@ -24,19 +24,26 @@ type ScoringInputs struct {
 	// user's taste, negative reflects passive avoidance, 0 when there's no
 	// profile signal (cold start / artist+tags absent from the profile).
 	TasteMatchScore float64
+	// ContextAffinityScore is the candidate artist's time-of-day/weekday
+	// affinity for the CURRENT context (#1531), in [-1, +1]: positive when the
+	// artist's plays concentrate in the current daypart × weekday-type cell
+	// more than the user's baseline, negative when under-represented, 0 when
+	// there's no history (cold-start neutral).
+	ContextAffinityScore float64
 }
 
 // ScoringWeights are the operator-tunable knobs. Defaults live in
 // config.RecommendationConfig and are propagated here per request.
 type ScoringWeights struct {
-	BaseWeight       float64
-	LikeBoost        float64
-	RecencyWeight    float64
-	SkipPenalty      float64
-	JitterMagnitude  float64
-	ContextWeight    float64
-	SimilarityWeight float64
-	TasteWeight      float64
+	BaseWeight        float64
+	LikeBoost         float64
+	RecencyWeight     float64
+	SkipPenalty       float64
+	JitterMagnitude   float64
+	ContextWeight     float64
+	SimilarityWeight  float64
+	TasteWeight       float64
+	ContextTimeWeight float64
 }
 
 // Score computes the weighted-shuffle score per spec §6:
@@ -48,6 +55,7 @@ type ScoringWeights struct {
 //	      + contextual_match_score * ContextWeight
 //	      + similarity_score * SimilarityWeight
 //	      + taste_match_score * TasteWeight
+//	      + context_affinity_score * ContextTimeWeight
 //	      + small_random_jitter
 //
 // Higher score = more likely to surface. rng is a function returning a
@@ -63,6 +71,7 @@ func Score(in ScoringInputs, w ScoringWeights, now time.Time, rng func() float64
 	s += in.ContextualMatchScore * w.ContextWeight
 	s += in.SimilarityScore * w.SimilarityWeight
 	s += in.TasteMatchScore * w.TasteWeight
+	s += in.ContextAffinityScore * w.ContextTimeWeight
 	s += (rng()*2 - 1) * w.JitterMagnitude
 	return s
 }

internal/recommendation/sessionvector.go

@@ -13,6 +13,11 @@ type SessionVector struct {
 	Artists        []string       `json:"artists"`
 	Tags           map[string]int `json:"tags"`
 	RecentTrackIDs []string       `json:"recent_track_ids"`
+	// DeviceClass is the current request's device (#1551), set by the radio
+	// handler from the user's latest play; drives the device dimension of the
+	// context-affinity term. Empty (omitted) for the daily mixes and for the
+	// snapshot stored on play_events, so it never narrows those.
+	DeviceClass string `json:"device_class,omitempty"`
 }
 
 func BuildSessionVector(priorTracks []dbq.Track) SessionVector {

internal/recommendation/taste.go

@@ -2,6 +2,7 @@ package recommendation
 
 import (
 	"context"
+	"fmt"
 	"math"
 
 	"github.com/jackc/pgx/v5/pgtype"
@@ -10,24 +11,37 @@ import (
 )
 
 // Taste-match tuning. The taste profile (written by internal/taste) holds
-// signed, unbounded artist/tag weights; these scales squash them into a
+// signed, unbounded artist/tag/era weights; these scales squash them into a
 // bounded [-1, +1] match via tanh, so one outlier artist can't compress the
 // rest toward zero (as a per-user max-normalisation would). A weight at the
 // scale value maps to tanh(1) ≈ 0.76 — "clearly a preference."
+//
+// The era (#1530) and mood (#1534) terms are added on TOP of artist+tag
+// (shares don't sum to 1) so they're pure nudges that never weaken the existing
+// artist/tag signal when a track lacks a date or mood tags; clampUnit bounds
+// the combined result. Their shares are small — both are coarse, partial-
+// coverage signals — and re-bakeable if the lab shows they should carry more.
 const (
 	tasteArtistScale  = 4.0
 	tasteTagScale     = 3.0
+	tasteEraScale     = 4.0
+	tasteMoodScale    = 3.0
 	tasteArtistShare  = 0.7
 	tasteTagShare     = 0.3
+	tasteEraShare     = 0.15
+	tasteMoodShare    = 0.12
 	tasteProfileLimit = 2000 // read cap; profiles are size-capped on write
 )
 
-// TasteProfile is the read-side view of a user's learned taste: signed
-// weights over artists and genre tags. The zero value (and any unknown
-// artist/tag) contributes 0, so cold-start users get no taste effect.
+// TasteProfile is the read-side view of a user's learned taste: signed weights
+// over artists, genre tags, decade/era buckets, and mood buckets. The zero
+// value (and any unknown key) contributes 0, so cold-start users get no taste
+// effect.
 type TasteProfile struct {
 	artists map[pgtype.UUID]float64
 	tags    map[string]float64
+	eras    map[string]float64
+	moods   map[string]float64
 }
 
 // LoadTasteProfile reads the user's taste profile from the taste_profile_*
@@ -46,9 +60,23 @@ func LoadTasteProfile(ctx context.Context, q *dbq.Queries, userID pgtype.UUID) (
 	if err != nil {
 		return TasteProfile{}, err
 	}
+	eras, err := q.ListTasteProfileErasForUser(ctx, dbq.ListTasteProfileErasForUserParams{
+		UserID: userID, Limit: tasteProfileLimit,
+	})
+	if err != nil {
+		return TasteProfile{}, err
+	}
+	moods, err := q.ListTasteProfileMoodsForUser(ctx, dbq.ListTasteProfileMoodsForUserParams{
+		UserID: userID, Limit: tasteProfileLimit,
+	})
+	if err != nil {
+		return TasteProfile{}, err
+	}
 	p := TasteProfile{
 		artists: make(map[pgtype.UUID]float64, len(arts)),
 		tags:    make(map[string]float64, len(tags)),
+		eras:    make(map[string]float64, len(eras)),
+		moods:   make(map[string]float64, len(moods)),
 	}
 	for _, a := range arts {
 		p.artists[a.ArtistID] = a.Weight
@@ -56,13 +84,23 @@ func LoadTasteProfile(ctx context.Context, q *dbq.Queries, userID pgtype.UUID) (
 	for _, t := range tags {
 		p.tags[t.Tag] = t.Weight
 	}
+	for _, e := range eras {
+		p.eras[e.Era] = e.Weight
+	}
+	for _, m := range moods {
+		p.moods[m.Mood] = m.Weight
+	}
 	return p, nil
 }
 
 // Match scores a candidate track's fit to the profile in [-1, +1]: a blend of
-// the artist's taste weight and the average of its genre tags' weights, each
-// tanh-squashed. Absent artist/tags contribute 0.
-func (p TasteProfile) Match(artistID pgtype.UUID, genre *string) float64 {
+// the artist's taste weight, the average of its genre tags' weights, its
+// decade/era weight, and the average of its mood buckets' weights, each
+// tanh-squashed. moods are the candidate's canonical mood buckets (from
+// internal/mood; nil when unknown). Absent artist/tags/era/moods contribute 0.
+func (p TasteProfile) Match(
+	artistID pgtype.UUID, genre *string, releaseDate pgtype.Date, moods []string,
+) float64 {
 	a := math.Tanh(p.artists[artistID] / tasteArtistScale)
 
 	var tg float64
@@ -76,7 +114,31 @@ func (p TasteProfile) Match(artistID pgtype.UUID, genre *string) float64 {
 			tg = math.Tanh((sum / float64(len(tags))) / tasteTagScale)
 		}
 	}
-	return clampUnit(tasteArtistShare*a + tasteTagShare*tg)
+
+	var er float64
+	if decade := decadeOf(releaseDate); decade != "" {
+		er = math.Tanh(p.eras[decade] / tasteEraScale)
+	}
+
+	var mo float64
+	if len(moods) > 0 {
+		var sum float64
+		for _, m := range moods {
+			sum += p.moods[m]
+		}
+		mo = math.Tanh((sum / float64(len(moods))) / tasteMoodScale)
+	}
+	return clampUnit(tasteArtistShare*a + tasteTagShare*tg + tasteEraShare*er + tasteMoodShare*mo)
+}
+
+// decadeOf maps an album release date to a decade bucket ("1990s"), or "" for
+// an absent date. Mirrors the taste builder's helper (kept local to avoid a
+// cross-package dependency) so a candidate's era is derived exactly as learned.
+func decadeOf(d pgtype.Date) string {
+	if !d.Valid {
+		return ""
+	}
+	return fmt.Sprintf("%ds", (d.Time.Year()/10)*10)
 }
 
 // clampUnit constrains x to [-1, 1].

internal/recommendation/taste_test.go

@@ -17,6 +17,14 @@ func uuidN(n byte) pgtype.UUID {
 
 func strPtr(s string) *string { return &s }
 
+// noDate is an absent release date — the era term contributes 0.
+func noDate() pgtype.Date { return pgtype.Date{} }
+
+// dateInYear builds a valid release date in the given year (era = its decade).
+func dateInYear(year int) pgtype.Date {
+	return pgtype.Date{Time: time.Date(year, 1, 1, 0, 0, 0, 0, time.UTC), Valid: true}
+}
+
 func TestTasteProfile_Match(t *testing.T) {
 	loved := uuidN(1)
 	disliked := uuidN(2)
@@ -26,32 +34,76 @@ func TestTasteProfile_Match(t *testing.T) {
 		tags:    map[string]float64{"Jazz": 6.0, "Noise": -6.0},
 	}
 
-	if m := p.Match(loved, strPtr("Jazz")); m <= 0.5 {
+	if m := p.Match(loved, strPtr("Jazz"), noDate(), nil); m <= 0.5 {
 		t.Errorf("loved artist + loved tag = %.3f, want strongly positive", m)
 	}
-	if m := p.Match(disliked, strPtr("Noise")); m >= -0.5 {
+	if m := p.Match(disliked, strPtr("Noise"), noDate(), nil); m >= -0.5 {
 		t.Errorf("disliked artist + disliked tag = %.3f, want strongly negative", m)
 	}
-	if m := p.Match(unknown, nil); m != 0 {
+	if m := p.Match(unknown, nil, noDate(), nil); m != 0 {
 		t.Errorf("unknown artist, no genre = %.3f, want 0", m)
 	}
 	// Artist dominates (0.7 share): loved artist with an unknown tag is still
 	// clearly positive.
-	if m := p.Match(loved, strPtr("Unheard")); m <= 0 {
+	if m := p.Match(loved, strPtr("Unheard"), noDate(), nil); m <= 0 {
 		t.Errorf("loved artist + unknown tag = %.3f, want positive", m)
 	}
 	// Output stays within [-1, 1] even with saturated inputs.
 	for _, a := range []pgtype.UUID{loved, disliked, unknown} {
-		m := p.Match(a, strPtr("Jazz"))
+		m := p.Match(a, strPtr("Jazz"), dateInYear(1994), nil)
 		if m < -1 || m > 1 {
 			t.Errorf("Match out of [-1,1]: %.3f", m)
 		}
 	}
 }
 
+// TestTasteProfile_EraTerm verifies the decade facet nudges the match: with
+// artist + genre held neutral, a loved era lifts the score and a disliked era
+// lowers it, while an undated track is unaffected.
+func TestTasteProfile_EraTerm(t *testing.T) {
+	art := uuidN(1)
+	p := TasteProfile{
+		artists: map[pgtype.UUID]float64{},
+		tags:    map[string]float64{},
+		eras:    map[string]float64{"1990s": 8.0, "1980s": -8.0},
+	}
+	loved := p.Match(art, nil, dateInYear(1994), nil)
+	if loved <= 0 {
+		t.Errorf("loved era (1990s) = %.3f, want positive", loved)
+	}
+	disliked := p.Match(art, nil, dateInYear(1987), nil)
+	if disliked >= 0 {
+		t.Errorf("disliked era (1980s) = %.3f, want negative", disliked)
+	}
+	if m := p.Match(art, nil, noDate(), nil); m != 0 {
+		t.Errorf("undated track = %.3f, want 0 (no era contribution)", m)
+	}
+}
+
+// TestTasteProfile_MoodTerm verifies the mood facet nudges the match: with
+// artist/genre/era neutral, a loved mood lifts the score and a disliked mood
+// lowers it, while a track with no mood buckets is unaffected.
+func TestTasteProfile_MoodTerm(t *testing.T) {
+	art := uuidN(1)
+	p := TasteProfile{
+		artists: map[pgtype.UUID]float64{},
+		tags:    map[string]float64{},
+		moods:   map[string]float64{"chill": 8.0, "aggressive": -8.0},
+	}
+	if m := p.Match(art, nil, noDate(), []string{"chill"}); m <= 0 {
+		t.Errorf("loved mood (chill) = %.3f, want positive", m)
+	}
+	if m := p.Match(art, nil, noDate(), []string{"aggressive"}); m >= 0 {
+		t.Errorf("disliked mood (aggressive) = %.3f, want negative", m)
+	}
+	if m := p.Match(art, nil, noDate(), nil); m != 0 {
+		t.Errorf("no moods = %.3f, want 0 (no mood contribution)", m)
+	}
+}
+
 func TestTasteProfile_EmptyIsNeutral(t *testing.T) {
 	var p TasteProfile // zero value: nil maps
-	if m := p.Match(uuidN(1), strPtr("Jazz")); m != 0 {
+	if m := p.Match(uuidN(1), strPtr("Jazz"), dateInYear(1994), nil); m != 0 {
 		t.Errorf("empty profile Match = %.3f, want 0 (cold start neutral)", m)
 	}
 }
@@ -100,10 +152,10 @@ func TestLoadTasteProfile_RoundTrip(t *testing.T) {
 	if err != nil {
 		t.Fatalf("load: %v", err)
 	}
-	if m := p.Match(art.ID, strPtr("Jazz")); m <= 0.5 {
+	if m := p.Match(art.ID, strPtr("Jazz"), noDate(), nil); m <= 0.5 {
 		t.Errorf("round-trip Match = %.3f, want strongly positive", m)
 	}
-	if m := p.Match(uuidN(9), nil); m != 0 {
+	if m := p.Match(uuidN(9), nil, noDate(), nil); m != 0 {
 		t.Errorf("absent artist Match = %.3f, want 0", m)
 	}
 }

internal/recsettings/patch.go

@@ -67,6 +67,10 @@ var weightFields = map[string]weightField{
 		get: func(w recommendation.ScoringWeights) float64 { return w.TasteWeight },
 		set: func(w *recommendation.ScoringWeights, v float64) { w.TasteWeight = v },
 	},
+	"context_time_weight": {
+		get: func(w recommendation.ScoringWeights) float64 { return w.ContextTimeWeight },
+		set: func(w *recommendation.ScoringWeights, v float64) { w.ContextTimeWeight = v },
+	},
 }
 
 // applyWeightPatch validates and applies a partial update, returning
@@ -129,6 +133,12 @@ func applyTastePatch(current TasteTuning, patch map[string]float64) (TasteTuning
 			target = &next.EngagementNeutral
 		case "engagement_full":
 			target = &next.EngagementFull
+		case "enriched_tag_scale":
+			target = &next.EnrichedTagScale
+		case "era_scale":
+			target = &next.EraScale
+		case "mood_scale":
+			target = &next.MoodScale
 		default:
 			return current, nil, fmt.Errorf("%w: %q", ErrUnknownField, field)
 		}
@@ -174,5 +184,8 @@ func diffTaste(a, b TasteTuning) []fieldChange {
 	add("engagement_hard_skip", a.EngagementHardSkip, b.EngagementHardSkip)
 	add("engagement_neutral", a.EngagementNeutral, b.EngagementNeutral)
 	add("engagement_full", a.EngagementFull, b.EngagementFull)
+	add("enriched_tag_scale", a.EnrichedTagScale, b.EnrichedTagScale)
+	add("era_scale", a.EraScale, b.EraScale)
+	add("mood_scale", a.MoodScale, b.MoodScale)
 	return out
 }

internal/recsettings/service.go

@@ -38,28 +38,36 @@ const (
 )
 
 // TasteTuning is the tunable subset of taste.Config: the engagement
-// half-life and the completion→engagement curve points.
+// half-life, the completion→engagement curve points, the enriched-tag
+// weight (how much folksonomy tags count vs raw ID3 genre, #1520), and the
+// era-facet weight (how strongly a decade-play imprints, #1530).
 type TasteTuning struct {
 	HalfLifeDays       float64
 	EngagementHardSkip float64
 	EngagementNeutral  float64
 	EngagementFull     float64
+	EnrichedTagScale   float64
+	EraScale           float64
+	MoodScale          float64
 }
 
 // ShippedRadioWeights are the shipped radio-profile defaults (moved
 // here from config.RecommendationConfig — YAML is bootstrap-only,
 // rule: config in UI). Radio is seed-directed (the user picked a
 // direction), so taste is a lighter nudge than in the daily mixes.
+// ContextTimeWeight starts uniform (1.0) across both profiles pending
+// trend data (#1531); split them once the metrics view justifies it.
 func ShippedRadioWeights() recommendation.ScoringWeights {
 	return recommendation.ScoringWeights{
-		BaseWeight:       1.0,
-		LikeBoost:        2.0,
-		RecencyWeight:    1.0,
-		SkipPenalty:      1.0,
-		JitterMagnitude:  0.1,
-		ContextWeight:    2.0,
-		SimilarityWeight: 2.0,
-		TasteWeight:      1.0,
+		BaseWeight:        1.0,
+		LikeBoost:         2.0,
+		RecencyWeight:     1.0,
+		SkipPenalty:       1.0,
+		JitterMagnitude:   0.1,
+		ContextWeight:     2.0,
+		SimilarityWeight:  2.0,
+		TasteWeight:       1.0,
+		ContextTimeWeight: 1.0,
 	}
 }
 
@@ -67,14 +75,15 @@ func ShippedRadioWeights() recommendation.ScoringWeights {
 // Must stay in sync with the pre-push literal in playlists/system.go.
 func ShippedDailyMixWeights() recommendation.ScoringWeights {
 	return recommendation.ScoringWeights{
-		BaseWeight:       1.0,
-		LikeBoost:        2.0,
-		RecencyWeight:    1.0,
-		SkipPenalty:      2.0,
-		JitterMagnitude:  0.1,
-		ContextWeight:    0.5,
-		SimilarityWeight: 1.5,
-		TasteWeight:      1.5,
+		BaseWeight:        1.0,
+		LikeBoost:         2.0,
+		RecencyWeight:     1.0,
+		SkipPenalty:       2.0,
+		JitterMagnitude:   0.1,
+		ContextWeight:     0.5,
+		SimilarityWeight:  1.5,
+		TasteWeight:       1.5,
+		ContextTimeWeight: 1.0,
 	}
 }
 
@@ -86,6 +95,9 @@ func ShippedTasteTuning() TasteTuning {
 		EngagementHardSkip: d.Engagement.HardSkip,
 		EngagementNeutral:  d.Engagement.NeutralCompletion,
 		EngagementFull:     d.Engagement.FullCompletion,
+		EnrichedTagScale:   d.EnrichedTagScale,
+		EraScale:           d.EraScale,
+		MoodScale:          d.MoodScale,
 	}
 }
 
@@ -133,6 +145,9 @@ func (s *Service) reconcile(ctx context.Context) error {
 		EngagementHardSkip: st.EngagementHardSkip,
 		EngagementNeutral:  st.EngagementNeutral,
 		EngagementFull:     st.EngagementFull,
+		EnrichedTagScale:   st.EnrichedTagScale,
+		EraScale:           st.EraScale,
+		MoodScale:          st.MoodScale,
 	}); err != nil {
 		return fmt.Errorf("seed taste tuning: %w", err)
 	}
@@ -156,6 +171,9 @@ func (s *Service) reconcile(ctx context.Context) error {
 		EngagementHardSkip: tt.EngagementHardSkip,
 		EngagementNeutral:  tt.EngagementNeutral,
 		EngagementFull:     tt.EngagementFull,
+		EnrichedTagScale:   tt.EnrichedTagScale,
+		EraScale:           tt.EraScale,
+		MoodScale:          tt.MoodScale,
 	}
 	s.mu.Unlock()
 
@@ -205,6 +223,9 @@ func (s *Service) TasteConfig() taste.Config {
 		NeutralCompletion: t.EngagementNeutral,
 		FullCompletion:    t.EngagementFull,
 	}
+	cfg.EnrichedTagScale = t.EnrichedTagScale
+	cfg.EraScale = t.EraScale
+	cfg.MoodScale = t.MoodScale
 	return cfg
 }
 
@@ -301,6 +322,9 @@ func (s *Service) persistTaste(
 		EngagementHardSkip: t.EngagementHardSkip,
 		EngagementNeutral:  t.EngagementNeutral,
 		EngagementFull:     t.EngagementFull,
+		EnrichedTagScale:   t.EnrichedTagScale,
+		EraScale:           t.EraScale,
+		MoodScale:          t.MoodScale,
 	}); err != nil {
 		return fmt.Errorf("update taste tuning: %w", err)
 	}
@@ -334,41 +358,44 @@ func (s *Service) audit(
 
 func upsertParams(profile string, w recommendation.ScoringWeights) dbq.UpsertWeightProfileDefaultsParams {
 	return dbq.UpsertWeightProfileDefaultsParams{
-		Profile:          profile,
-		BaseWeight:       w.BaseWeight,
-		LikeBoost:        w.LikeBoost,
-		RecencyWeight:    w.RecencyWeight,
-		SkipPenalty:      w.SkipPenalty,
-		JitterMagnitude:  w.JitterMagnitude,
-		ContextWeight:    w.ContextWeight,
-		SimilarityWeight: w.SimilarityWeight,
-		TasteWeight:      w.TasteWeight,
+		Profile:           profile,
+		BaseWeight:        w.BaseWeight,
+		LikeBoost:         w.LikeBoost,
+		RecencyWeight:     w.RecencyWeight,
+		SkipPenalty:       w.SkipPenalty,
+		JitterMagnitude:   w.JitterMagnitude,
+		ContextWeight:     w.ContextWeight,
+		SimilarityWeight:  w.SimilarityWeight,
+		TasteWeight:       w.TasteWeight,
+		ContextTimeWeight: w.ContextTimeWeight,
 	}
 }
 
 func updateParams(profile string, w recommendation.ScoringWeights) dbq.UpdateWeightProfileParams {
 	return dbq.UpdateWeightProfileParams{
-		Profile:          profile,
-		BaseWeight:       w.BaseWeight,
-		LikeBoost:        w.LikeBoost,
-		RecencyWeight:    w.RecencyWeight,
-		SkipPenalty:      w.SkipPenalty,
-		JitterMagnitude:  w.JitterMagnitude,
-		ContextWeight:    w.ContextWeight,
-		SimilarityWeight: w.SimilarityWeight,
-		TasteWeight:      w.TasteWeight,
+		Profile:           profile,
+		BaseWeight:        w.BaseWeight,
+		LikeBoost:         w.LikeBoost,
+		RecencyWeight:     w.RecencyWeight,
+		SkipPenalty:       w.SkipPenalty,
+		JitterMagnitude:   w.JitterMagnitude,
+		ContextWeight:     w.ContextWeight,
+		SimilarityWeight:  w.SimilarityWeight,
+		TasteWeight:       w.TasteWeight,
+		ContextTimeWeight: w.ContextTimeWeight,
 	}
 }
 
 func weightsFromRow(r dbq.RecommendationWeightProfile) recommendation.ScoringWeights {
 	return recommendation.ScoringWeights{
-		BaseWeight:       r.BaseWeight,
-		LikeBoost:        r.LikeBoost,
-		RecencyWeight:    r.RecencyWeight,
-		SkipPenalty:      r.SkipPenalty,
-		JitterMagnitude:  r.JitterMagnitude,
-		ContextWeight:    r.ContextWeight,
-		SimilarityWeight: r.SimilarityWeight,
-		TasteWeight:      r.TasteWeight,
+		BaseWeight:        r.BaseWeight,
+		LikeBoost:         r.LikeBoost,
+		RecencyWeight:     r.RecencyWeight,
+		SkipPenalty:       r.SkipPenalty,
+		JitterMagnitude:   r.JitterMagnitude,
+		ContextWeight:     r.ContextWeight,
+		SimilarityWeight:  r.SimilarityWeight,
+		TasteWeight:       r.TasteWeight,
+		ContextTimeWeight: r.ContextTimeWeight,
 	}
 }

internal/recsettings/service_test.go

@@ -182,6 +182,67 @@ func TestUpdateTaste_CurveOrderingEnforced(t *testing.T) {
 	}
 }
 
+func TestUpdateTaste_EnrichedTagScale(t *testing.T) {
+	pool := newPool(t)
+	s := newService(t, pool)
+	// In-range update persists into cache + the assembled taste config.
+	if err := s.UpdateTaste(context.Background(),
+		map[string]float64{"enriched_tag_scale": 0.8}); err != nil {
+		t.Fatalf("UpdateTaste: %v", err)
+	}
+	if got := s.Taste().EnrichedTagScale; got != 0.8 {
+		t.Errorf("Taste().EnrichedTagScale = %v, want 0.8", got)
+	}
+	if got := s.TasteConfig().EnrichedTagScale; got != 0.8 {
+		t.Errorf("TasteConfig().EnrichedTagScale = %v, want 0.8", got)
+	}
+	// Out of [0,1] rejects.
+	if err := s.UpdateTaste(context.Background(),
+		map[string]float64{"enriched_tag_scale": 1.5}); !errors.Is(err, ErrOutOfRange) {
+		t.Errorf("err = %v, want ErrOutOfRange for 1.5", err)
+	}
+}
+
+func TestUpdateTaste_EraScale(t *testing.T) {
+	pool := newPool(t)
+	s := newService(t, pool)
+	// In-range update persists into cache + the assembled taste config.
+	if err := s.UpdateTaste(context.Background(),
+		map[string]float64{"era_scale": 0.8}); err != nil {
+		t.Fatalf("UpdateTaste: %v", err)
+	}
+	if got := s.Taste().EraScale; got != 0.8 {
+		t.Errorf("Taste().EraScale = %v, want 0.8", got)
+	}
+	if got := s.TasteConfig().EraScale; got != 0.8 {
+		t.Errorf("TasteConfig().EraScale = %v, want 0.8", got)
+	}
+	// Out of [0,1] rejects.
+	if err := s.UpdateTaste(context.Background(),
+		map[string]float64{"era_scale": 1.5}); !errors.Is(err, ErrOutOfRange) {
+		t.Errorf("err = %v, want ErrOutOfRange for 1.5", err)
+	}
+}
+
+func TestUpdateTaste_MoodScale(t *testing.T) {
+	pool := newPool(t)
+	s := newService(t, pool)
+	if err := s.UpdateTaste(context.Background(),
+		map[string]float64{"mood_scale": 0.8}); err != nil {
+		t.Fatalf("UpdateTaste: %v", err)
+	}
+	if got := s.Taste().MoodScale; got != 0.8 {
+		t.Errorf("Taste().MoodScale = %v, want 0.8", got)
+	}
+	if got := s.TasteConfig().MoodScale; got != 0.8 {
+		t.Errorf("TasteConfig().MoodScale = %v, want 0.8", got)
+	}
+	if err := s.UpdateTaste(context.Background(),
+		map[string]float64{"mood_scale": 1.5}); !errors.Is(err, ErrOutOfRange) {
+		t.Errorf("err = %v, want ErrOutOfRange for 1.5", err)
+	}
+}
+
 func TestReset_RestoresShippedAndAudits(t *testing.T) {
 	pool := newPool(t)
 	s := newService(t, pool)

internal/tags/enricher.go

@@ -171,6 +171,9 @@ func (e *Enricher) EnrichTrackBatch(ctx context.Context, limit int,
 		if r.Mbid != nil {
 			ref.MBID = *r.Mbid
 		}
+		if r.ArtistMbid != nil {
+			ref.ArtistMBID = *r.ArtistMbid
+		}
 		oc, eerr := e.EnrichTrack(ctx, r.ID, ref)
 		if eerr != nil {
 			e.logger.Warn("tags: batch entry failed", "track_id", uuidString(r.ID), "err", eerr)

internal/tags/provider.go

@@ -32,11 +32,14 @@ type Tag struct {
 
 // TrackRef is the lookup key passed to a provider. MBID is the track's
 // recording MBID (preferred by MBID-keyed providers); ArtistName + Title
-// are the always-populated fallback for name-based providers (Last.fm).
+// are the always-populated fallback for name-based providers (Last.fm);
+// ArtistMBID (nullable) enables MusicBrainz's artist-tag fallback (#1519)
+// when the recording itself is untagged or MBID-less.
 type TrackRef struct {
 	MBID       string
 	ArtistName string
 	Title      string
+	ArtistMBID string
 }
 
 // Provider is the base shape every tag source implements. Providers

internal/tags/provider_musicbrainz.go

@@ -17,13 +17,18 @@ const (
 	mbMinPeriod = 1100 * time.Millisecond
 	// mbUserAgent identifies the app — MusicBrainz rejects requests without one.
 	mbUserAgent = "Minstrel/1.0 ( https://git.fabledsword.com/bvandeusen/minstrel )"
+	// artistTagWeightFactor down-weights artist-level fallback tags relative
+	// to recording-specific tags — the artist's overall character is a coarser
+	// signal than a tag on the exact recording (#1519).
+	artistTagWeightFactor = 0.6
 )
 
-// musicbrainzProvider fetches recording-level folksonomy tags from the
-// MusicBrainz web service. Keyless (the public endpoint needs no auth) and
-// on by default — the always-available baseline source. MBID-only: a track
-// with no recording MBID yields ErrNotFound (name search is ambiguous for
-// recordings and deferred to name-based providers like Last.fm).
+// musicbrainzProvider fetches folksonomy tags from the MusicBrainz web
+// service. Keyless (the public endpoint needs no auth) and on by default —
+// the always-available baseline source. Prefers recording-level tags by the
+// track's recording MBID; when the recording is untagged or MBID-less it
+// falls back to the artist's tags by artist MBID (#1519), down-weighted as a
+// coarser signal. Name-based lookup is deferred to providers like Last.fm.
 type musicbrainzProvider struct {
 	enabled atomic.Bool
 	client  *httpClient
@@ -61,24 +66,54 @@ type mbTag struct {
 	Name  string `json:"name"`
 }
 
-// FetchTrackTags looks up the recording's tags by MBID. Returns ErrNotFound
-// when disabled, when the track has no MBID, or when MusicBrainz has no tags.
+// FetchTrackTags looks up recording tags by MBID, then falls back to artist
+// tags by artist MBID when the recording is untagged or MBID-less. Returns
+// ErrNotFound when disabled or when neither level yields tags. A transient
+// error at the recording step is returned as-is (retry) rather than silently
+// masked by the artist fallback.
 func (p *musicbrainzProvider) FetchTrackTags(ctx context.Context, ref TrackRef) ([]Tag, error) {
-	if !p.enabled.Load() || ref.MBID == "" {
+	if !p.enabled.Load() {
 		return nil, ErrNotFound
 	}
-	q := url.Values{"inc": {"tags"}, "fmt": {"json"}}
-	full := mbBaseURL + "/recording/" + url.PathEscape(ref.MBID) + "?" + q.Encode()
+	if ref.MBID != "" {
+		tags, err := p.fetchEntityTags(ctx, "recording", ref.MBID, 1.0)
+		if err != nil && !errors.Is(err, ErrNotFound) {
+			return nil, err
+		}
+		if len(tags) > 0 {
+			return tags, nil
+		}
+	}
+	if ref.ArtistMBID != "" {
+		tags, err := p.fetchEntityTags(ctx, "artist", ref.ArtistMBID, artistTagWeightFactor)
+		if err != nil && !errors.Is(err, ErrNotFound) {
+			return nil, err
+		}
+		if len(tags) > 0 {
+			return tags, nil
+		}
+	}
+	return nil, ErrNotFound
+}
 
+// fetchEntityTags loads folksonomy tags for a MusicBrainz entity ("recording"
+// or "artist") by MBID and scales the normalized weights by `scale`. Returns
+// an empty slice (not ErrNotFound) when the entity exists but is untagged, so
+// the caller can decide whether to fall through to the next level.
+func (p *musicbrainzProvider) fetchEntityTags(ctx context.Context, entity, mbid string, scale float64) ([]Tag, error) {
+	q := url.Values{"inc": {"tags"}, "fmt": {"json"}}
+	full := mbBaseURL + "/" + entity + "/" + url.PathEscape(mbid) + "?" + q.Encode()
 	var resp mbTagsResponse
 	if err := p.client.getJSON(ctx, full, &resp); err != nil {
 		return nil, err
 	}
-	out := normalizeMBTags(resp.Tags)
-	if len(out) == 0 {
-		return nil, ErrNotFound
+	tags := normalizeMBTags(resp.Tags)
+	if scale != 1.0 {
+		for i := range tags {
+			tags[i].Weight *= scale
+		}
 	}
-	return out, nil
+	return tags, nil
 }
 
 // TestConnection issues a tiny search request; any non-transient response

internal/tags/provider_musicbrainz_test.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"net/http"
 	"net/http/httptest"
+	"strings"
 	"testing"
 )
 
@@ -50,13 +51,98 @@ func TestMusicBrainzFetch_GatedOff(t *testing.T) {
 		TrackRef{MBID: "abc"}); !errors.Is(err, ErrNotFound) {
 		t.Errorf("disabled: err = %v, want ErrNotFound", err)
 	}
-	// No MBID → ErrNotFound (MBID-only provider).
+	// No recording MBID and no artist MBID → nothing to look up → ErrNotFound.
 	if _, err := newMBProvider(true).FetchTrackTags(context.Background(),
 		TrackRef{ArtistName: "A", Title: "B"}); !errors.Is(err, ErrNotFound) {
 		t.Errorf("no MBID: err = %v, want ErrNotFound", err)
 	}
 }
 
+// mbEntityServer returns tags keyed by entity path segment ("recording" or
+// "artist"), so a test can make the recording untagged while the artist has
+// tags (or vice-versa). An empty body string means "{tags:[]}".
+func mbEntityServer(recordingJSON, artistJSON string) *httptest.Server {
+	empty := `{"tags":[]}`
+	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		body := empty
+		switch {
+		case strings.Contains(r.URL.Path, "/recording/"):
+			if recordingJSON != "" {
+				body = recordingJSON
+			}
+		case strings.Contains(r.URL.Path, "/artist/"):
+			if artistJSON != "" {
+				body = artistJSON
+			}
+		}
+		_, _ = w.Write([]byte(body))
+	}))
+}
+
+func TestMusicBrainzFetch_ArtistFallbackWhenRecordingUntagged(t *testing.T) {
+	// Recording exists but has no tags; artist has tags → use the artist's,
+	// down-weighted by artistTagWeightFactor.
+	srv := mbEntityServer(``, `{"tags":[{"count":4,"name":"art rock"},{"count":2,"name":"experimental"}]}`)
+	defer srv.Close()
+	old := mbBaseURL
+	mbBaseURL = srv.URL
+	defer func() { mbBaseURL = old }()
+
+	tags, err := newMBProvider(true).FetchTrackTags(context.Background(),
+		TrackRef{MBID: "rec-1", ArtistMBID: "art-1"})
+	if err != nil {
+		t.Fatalf("fetch: %v", err)
+	}
+	m := tagsByName(tags)
+	// "art rock" is the top artist tag (weight 1.0) × 0.6 fallback factor.
+	if got := m["art rock"]; got != 0.6 {
+		t.Errorf("art rock = %v, want 0.6 (down-weighted)", got)
+	}
+	if got := m["experimental"]; got != 0.3 { // 0.5 × 0.6
+		t.Errorf("experimental = %v, want 0.3", got)
+	}
+}
+
+func TestMusicBrainzFetch_ArtistOnlyWhenNoRecordingMBID(t *testing.T) {
+	srv := mbEntityServer(``, `{"tags":[{"count":1,"name":"folk"}]}`)
+	defer srv.Close()
+	old := mbBaseURL
+	mbBaseURL = srv.URL
+	defer func() { mbBaseURL = old }()
+
+	tags, err := newMBProvider(true).FetchTrackTags(context.Background(),
+		TrackRef{ArtistName: "A", Title: "B", ArtistMBID: "art-2"})
+	if err != nil {
+		t.Fatalf("fetch: %v", err)
+	}
+	if got := tagsByName(tags)["folk"]; got != 0.6 {
+		t.Errorf("folk = %v, want 0.6", got)
+	}
+}
+
+func TestMusicBrainzFetch_RecordingPreferredOverArtist(t *testing.T) {
+	// Recording has tags → they win at full weight; artist is never consulted.
+	srv := mbEntityServer(`{"tags":[{"count":3,"name":"shoegaze"}]}`,
+		`{"tags":[{"count":9,"name":"rock"}]}`)
+	defer srv.Close()
+	old := mbBaseURL
+	mbBaseURL = srv.URL
+	defer func() { mbBaseURL = old }()
+
+	tags, err := newMBProvider(true).FetchTrackTags(context.Background(),
+		TrackRef{MBID: "rec-2", ArtistMBID: "art-3"})
+	if err != nil {
+		t.Fatalf("fetch: %v", err)
+	}
+	m := tagsByName(tags)
+	if got := m["shoegaze"]; got != 1.0 {
+		t.Errorf("shoegaze = %v, want 1.0 (recording, full weight)", got)
+	}
+	if _, ok := m["rock"]; ok {
+		t.Error("artist tag 'rock' leaked in — recording tags should win outright")
+	}
+}
+
 func TestMusicBrainzFetch_ParsesTags(t *testing.T) {
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 		_, _ = w.Write([]byte(`{"tags":[{"count":2,"name":"post-punk"},{"count":4,"name":"melancholic"}]}`))

internal/taste/profile.go

@@ -16,6 +16,7 @@ import (
 	"github.com/jackc/pgx/v5/pgxpool"
 
 	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/mood"
 )
 
 // Config holds the operator-tunable knobs. DefaultConfig supplies tuned
@@ -46,6 +47,21 @@ type Config struct {
 	// contribution entirely (falls back to genre-only).
 	EnrichedTagScale float64
 
+	// EraScale weights the decade/era facet (#1530): each play adds
+	// base × this scale to its album's decade bucket ("1990s"), where base
+	// is the decayed engagement (or the tag-like bonus for a liked track).
+	// Era is a coarse signal, so it's kept ≤ 1 to imprint at most as strongly
+	// as the raw engagement; 0 disables the era facet entirely. Tunable in the
+	// lab (mirrors EnrichedTagScale, #1520).
+	EraScale float64
+
+	// MoodScale weights the mood facet (#1534): each play adds base × this
+	// scale to the canonical mood buckets (melancholic / chill / …) derived
+	// from its enriched folksonomy tags via internal/mood. Coverage is partial
+	// (depends on tag enrichment), so it's a supplement kept ≤ 1; 0 disables
+	// the mood facet entirely. Tunable in the lab (mirrors EraScale).
+	MoodScale float64
+
 	// ArtistFloor / TagFloor clamp how negative a single entity's weight may
 	// go. Aggregation already protects an artist the user likes (one skip
 	// nets out against many good plays); the floor additionally bounds the
@@ -58,11 +74,17 @@ type Config struct {
 	WeightEpsilon float64
 
 	// Size caps (guard rails for pathological libraries). Persist the top
-	// MaxArtists by weight plus the most-negative MaxNegArtists; same for tags.
+	// MaxArtists by weight plus the most-negative MaxNegArtists; same for tags
+	// and eras. Real libraries span ~a dozen decades, so the era caps rarely
+	// bind — they exist for symmetry with the other facets.
 	MaxArtists    int
 	MaxNegArtists int
 	MaxTags       int
 	MaxNegTags    int
+	MaxEras       int
+	MaxNegEras    int
+	MaxMoods      int
+	MaxNegMoods   int
 }
 
 // DefaultConfig returns the tuned starting configuration.
@@ -75,6 +97,8 @@ func DefaultConfig() Config {
 		TrackLikeBonus:   1.0,
 		TagLikeBonus:     0.5,
 		EnrichedTagScale: 0.5,
+		EraScale:         0.5,
+		MoodScale:        0.5,
 		ArtistFloor:      -3.0,
 		TagFloor:         -3.0,
 		WeightEpsilon:    0.05,
@@ -82,6 +106,10 @@ func DefaultConfig() Config {
 		MaxNegArtists:    150,
 		MaxTags:          200,
 		MaxNegTags:       60,
+		MaxEras:          30,
+		MaxNegEras:       15,
+		MaxMoods:         20,
+		MaxNegMoods:      10,
 	}
 }
 
@@ -101,36 +129,42 @@ func BuildTasteProfile(
 ) error {
 	q := dbq.New(pool)
 
-	artistW, tagW, err := accumulate(ctx, q, userID, cfg)
+	artistW, tagW, eraW, moodW, err := accumulate(ctx, q, userID, cfg)
 	if err != nil {
 		return err
 	}
 	applyFloor(artistW, cfg.ArtistFloor)
 	applyFloor(tagW, cfg.TagFloor)
+	// Era + mood share the tag floor (all text-keyed facets; a decade or mood
+	// that's been heavily skipped shouldn't dominate as an extreme negative).
+	applyFloor(eraW, cfg.TagFloor)
+	applyFloor(moodW, cfg.TagFloor)
 
+	strLess := func(a, b string) bool { return a < b }
 	artists := rankWeighted(artistW, cfg.WeightEpsilon, cfg.MaxArtists, cfg.MaxNegArtists, uuidLess)
-	tags := rankWeighted(tagW, cfg.WeightEpsilon, cfg.MaxTags, cfg.MaxNegTags,
-		func(a, b string) bool { return a < b })
+	tags := rankWeighted(tagW, cfg.WeightEpsilon, cfg.MaxTags, cfg.MaxNegTags, strLess)
+	eras := rankWeighted(eraW, cfg.WeightEpsilon, cfg.MaxEras, cfg.MaxNegEras, strLess)
+	moods := rankWeighted(moodW, cfg.WeightEpsilon, cfg.MaxMoods, cfg.MaxNegMoods, strLess)
 
-	if err := persist(ctx, pool, userID, artists, tags); err != nil {
+	if err := persist(ctx, pool, userID, artists, tags, eras, moods); err != nil {
 		return err
 	}
-	logger.Debug("taste: profile rebuilt",
-		"user_id", uuidString(userID), "artists", len(artists), "tags", len(tags))
+	logger.Debug("taste: profile rebuilt", "user_id", uuidString(userID),
+		"artists", len(artists), "tags", len(tags), "eras", len(eras), "moods", len(moods))
 	return nil
 }
 
-// accumulate sums decayed play engagement and like bonuses into artist/tag
-// weight maps.
+// accumulate sums decayed play engagement and like bonuses into
+// artist/tag/era/mood weight maps.
 func accumulate(
 	ctx context.Context, q *dbq.Queries, userID pgtype.UUID, cfg Config,
-) (map[pgtype.UUID]float64, map[string]float64, error) {
+) (map[pgtype.UUID]float64, map[string]float64, map[string]float64, map[string]float64, error) {
 	plays, err := q.ListPlayEngagementInputsForUser(ctx, dbq.ListPlayEngagementInputsForUserParams{
 		UserID:  userID,
 		Column2: cfg.WindowDays,
 	})
 	if err != nil {
-		return nil, nil, fmt.Errorf("taste: load play engagement: %w", err)
+		return nil, nil, nil, nil, fmt.Errorf("taste: load play engagement: %w", err)
 	}
 	// Enriched folksonomy tags keyed by track (#1490) — folded into the tag
 	// facet alongside raw ID3 genre so a coarse "Rock" gains the cached
@@ -141,12 +175,14 @@ func accumulate(
 		Column2: int32(cfg.WindowDays),
 	})
 	if err != nil {
-		return nil, nil, fmt.Errorf("taste: load played track tags: %w", err)
+		return nil, nil, nil, nil, fmt.Errorf("taste: load played track tags: %w", err)
 	}
 	playedTags := groupTagsByTrack(playedTagRows)
 
 	artistW := make(map[pgtype.UUID]float64)
 	tagW := make(map[string]float64)
+	eraW := make(map[string]float64)
+	moodW := make(map[string]float64)
 	for _, p := range plays {
 		e := Engagement(p.Completion, cfg.Engagement) * decay(p.AgeDays, cfg.HalfLifeDays)
 		artistW[p.ArtistID] += e
@@ -154,15 +190,17 @@ func accumulate(
 			tagW[tag] += e
 		}
 		foldEnrichedTags(tagW, playedTags[p.TrackID], e, cfg.EnrichedTagScale)
+		foldEra(eraW, p.ReleaseDate, e, cfg.EraScale)
+		foldMoods(moodW, playedTags[p.TrackID], e, cfg.MoodScale)
 	}
 
 	likedTracks, err := q.ListLikedTrackTasteInputsForUser(ctx, userID)
 	if err != nil {
-		return nil, nil, fmt.Errorf("taste: load liked tracks: %w", err)
+		return nil, nil, nil, nil, fmt.Errorf("taste: load liked tracks: %w", err)
 	}
 	likedTagRows, err := q.ListLikedTrackTagsForUser(ctx, userID)
 	if err != nil {
-		return nil, nil, fmt.Errorf("taste: load liked track tags: %w", err)
+		return nil, nil, nil, nil, fmt.Errorf("taste: load liked track tags: %w", err)
 	}
 	likedTags := groupTagsByTrack(likedTagRows)
 	for _, lt := range likedTracks {
@@ -171,16 +209,18 @@ func accumulate(
 			tagW[tag] += cfg.TagLikeBonus
 		}
 		foldEnrichedTags(tagW, likedTags[lt.TrackID], cfg.TagLikeBonus, cfg.EnrichedTagScale)
+		foldEra(eraW, lt.ReleaseDate, cfg.TagLikeBonus, cfg.EraScale)
+		foldMoods(moodW, likedTags[lt.TrackID], cfg.TagLikeBonus, cfg.MoodScale)
 	}
 
 	likedArtists, err := q.ListLikedArtistIDsForUser(ctx, userID)
 	if err != nil {
-		return nil, nil, fmt.Errorf("taste: load liked artists: %w", err)
+		return nil, nil, nil, nil, fmt.Errorf("taste: load liked artists: %w", err)
 	}
 	for _, aid := range likedArtists {
 		artistW[aid] += cfg.ArtistLikeBonus
 	}
-	return artistW, tagW, nil
+	return artistW, tagW, eraW, moodW, nil
 }
 
 // groupTagsByTrack buckets flat (track, tag, weight) rows by track id so
@@ -206,10 +246,51 @@ func foldEnrichedTags(tagW map[string]float64, tags []dbq.TrackTag, base, scale
 	}
 }
 
+// foldEra adds a track's decade bucket to eraW weighted by base × scale — base
+// is the play's decayed engagement or the tag-like bonus, scale (EraScale)
+// dials the facet's strength. scale=0 disables the era facet; undated tracks
+// (decade "") contribute nothing so they don't pollute the profile.
+func foldEra(eraW map[string]float64, d pgtype.Date, base, scale float64) {
+	if scale == 0 {
+		return
+	}
+	if decade := decadeOf(d); decade != "" {
+		eraW[decade] += base * scale
+	}
+}
+
+// foldMoods adds a track's canonical mood buckets (derived from its enriched
+// folksonomy tags via internal/mood) to moodW weighted by base × scale. base is
+// the play's decayed engagement or the tag-like bonus; scale (MoodScale) dials
+// the facet's strength. scale=0 disables the mood facet; tracks with no
+// mood-word tags contribute nothing.
+func foldMoods(moodW map[string]float64, tags []dbq.TrackTag, base, scale float64) {
+	if scale == 0 {
+		return
+	}
+	names := make([]string, len(tags))
+	for i, t := range tags {
+		names[i] = t.Tag
+	}
+	for _, m := range mood.Of(names) {
+		moodW[m] += base * scale
+	}
+}
+
+// decadeOf maps an album release date to a decade bucket like "1990s", or ""
+// for an absent/invalid date. Mirrored by the recommendation scorer so a
+// candidate's era is derived the same way it was learned.
+func decadeOf(d pgtype.Date) string {
+	if !d.Valid {
+		return ""
+	}
+	return fmt.Sprintf("%ds", (d.Time.Year()/10)*10)
+}
+
 // persist atomic-replaces the user's profile rows inside one transaction.
 func persist(
 	ctx context.Context, pool *pgxpool.Pool, userID pgtype.UUID,
-	artists []weighted[pgtype.UUID], tags []weighted[string],
+	artists []weighted[pgtype.UUID], tags, eras, moods []weighted[string],
 ) error {
 	tx, err := pool.Begin(ctx)
 	if err != nil {
@@ -238,6 +319,26 @@ func persist(
 			return fmt.Errorf("taste: insert tag: %w", err)
 		}
 	}
+	if err := qtx.DeleteTasteProfileErasForUser(ctx, userID); err != nil {
+		return fmt.Errorf("taste: delete eras: %w", err)
+	}
+	for _, e := range eras {
+		if err := qtx.InsertTasteProfileEra(ctx, dbq.InsertTasteProfileEraParams{
+			UserID: userID, Era: e.Key, Weight: e.Weight,
+		}); err != nil {
+			return fmt.Errorf("taste: insert era: %w", err)
+		}
+	}
+	if err := qtx.DeleteTasteProfileMoodsForUser(ctx, userID); err != nil {
+		return fmt.Errorf("taste: delete moods: %w", err)
+	}
+	for _, m := range moods {
+		if err := qtx.InsertTasteProfileMood(ctx, dbq.InsertTasteProfileMoodParams{
+			UserID: userID, Mood: m.Key, Weight: m.Weight,
+		}); err != nil {
+			return fmt.Errorf("taste: insert mood: %w", err)
+		}
+	}
 	if err := tx.Commit(ctx); err != nil {
 		return fmt.Errorf("taste: commit: %w", err)
 	}

renovate.json

@@ -0,0 +1,61 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    "config:recommended",
+    ":semanticCommits"
+  ],
+  "baseBranches": ["dev"],
+  "timezone": "America/New_York",
+  "schedule": ["every weekend"],
+  "prHourlyLimit": 2,
+  "prConcurrentLimit": 8,
+  "ignorePaths": [
+    "**/node_modules/**",
+    "**/vendor/**",
+    "flutter_client/**"
+  ],
+  "lockFileMaintenance": {
+    "enabled": true,
+    "schedule": ["before 5am on the first day of the month"]
+  },
+  "packageRules": [
+    {
+      "description": "Auto-merge patch/minor/digest/pin bumps once CI is green",
+      "matchUpdateTypes": ["minor", "patch", "digest", "pin"],
+      "automerge": true
+    },
+    {
+      "description": "Hold all major bumps for manual approval via the dependency dashboard",
+      "matchUpdateTypes": ["major"],
+      "automerge": false,
+      "dependencyDashboardApproval": true,
+      "addLabels": ["deps", "deps:major"]
+    },
+    {
+      "description": "Group Go module updates into one PR",
+      "matchManagers": ["gomod"],
+      "groupName": "go modules"
+    },
+    {
+      "description": "Group CI workflow action bumps",
+      "matchManagers": ["github-actions"],
+      "groupName": "ci actions"
+    },
+    {
+      "description": "Group Docker base-image bumps (Dockerfile + compose)",
+      "matchManagers": ["dockerfile", "docker-compose"],
+      "groupName": "docker images"
+    },
+    {
+      "description": "Group the Android Gradle/Kotlin toolchain",
+      "matchManagers": ["gradle", "gradle-wrapper"],
+      "groupName": "android gradle"
+    },
+    {
+      "description": "Group web npm non-major bumps",
+      "matchManagers": ["npm"],
+      "matchUpdateTypes": ["minor", "patch"],
+      "groupName": "web npm (non-major)"
+    }
+  ]
+}

web/src/lib/api/tuning.ts

@@ -13,6 +13,7 @@ export type WeightProfile = {
   context_weight: number;
   similarity_weight: number;
   taste_weight: number;
+  context_time_weight: number;
 };
 
 export type TasteTuning = {
@@ -20,6 +21,9 @@ export type TasteTuning = {
   engagement_hard_skip: number;
   engagement_neutral: number;
   engagement_full: number;
+  enriched_tag_scale: number;
+  era_scale: number;
+  mood_scale: number;
 };
 
 export type TuningScope = 'radio' | 'daily_mix' | 'taste';

web/src/lib/player/events.svelte.ts

@@ -124,7 +124,10 @@ export function useEventsDispatcher(): void {
         // #415: tag the play with the system playlist it came from
         // (null for library / user-playlist / radio) so the server
         // can advance that playlist's rotation.
-        source: player.queueSource ?? undefined
+        source: player.queueSource ?? undefined,
+        // #1551: device class for context conditioning. The web app is a
+        // browser session, so it reports 'web'.
+        device_class: 'web'
       });
       // The user may have moved on by the time the response arrives. Only
       // adopt the id if we're still on the same track and still playing.

web/src/routes/admin/tuning/+page.svelte

@@ -29,14 +29,18 @@
     { key: 'jitter_magnitude',  label: 'Jitter',            hint: 'Random reshuffle magnitude for near-ties.' },
     { key: 'context_weight',    label: 'Context weight',    hint: 'Session-vector similarity contribution.' },
     { key: 'similarity_weight', label: 'Similarity weight', hint: 'Seed-similarity contribution.' },
-    { key: 'taste_weight',      label: 'Taste weight',      hint: 'Learned taste-profile fit, in [-1, +1].' }
+    { key: 'taste_weight',      label: 'Taste weight',      hint: 'Learned taste-profile fit, in [-1, +1].' },
+    { key: 'context_time_weight', label: 'Time-of-day weight', hint: "Artist's time-of-day/weekday affinity for the current context, in [-1, +1]. 0 = ignore when you listen." }
   ];
 
   const tasteFields: { key: keyof TasteTuning; label: string; hint: string }[] = [
     { key: 'half_life_days',       label: 'Half-life (days)', hint: "A play's influence halves every this-many days." },
     { key: 'engagement_hard_skip', label: 'Hard-skip point',  hint: 'Completion at/below which a play reads −1.' },
     { key: 'engagement_neutral',   label: 'Neutral point',    hint: 'Completion at which a play reads 0.' },
-    { key: 'engagement_full',      label: 'Full point',       hint: 'Completion at/above which a play reads +1.' }
+    { key: 'engagement_full',      label: 'Full point',       hint: 'Completion at/above which a play reads +1.' },
+    { key: 'enriched_tag_scale',   label: 'Enriched tag weight', hint: 'How much folksonomy tags (MusicBrainz/Last.fm) count vs raw file genre, in [0, 1]. 0 = genre only.' },
+    { key: 'era_scale',            label: 'Era weight', hint: 'How strongly a decade-play imprints on the era facet, in [0, 1]. 0 = era ignored.' },
+    { key: 'mood_scale',           label: 'Mood weight', hint: 'How strongly a mood-tagged play imprints on the mood facet (from folksonomy tags), in [0, 1]. 0 = mood ignored.' }
   ];
 
   const profileScopes: { scope: 'radio' | 'daily_mix'; label: string; blurb: string }[] = [

web/src/routes/admin/tuning/tuning.test.ts

@@ -28,6 +28,7 @@ const weights = (over: Partial<Record<string, number>> = {}) => ({
   context_weight: 0.5,
   similarity_weight: 1.5,
   taste_weight: 1.5,
+  context_time_weight: 1,
   ...over
 });
 
@@ -36,6 +37,9 @@ const taste = (over: Partial<Record<string, number>> = {}) => ({
   engagement_hard_skip: 0.05,
   engagement_neutral: 0.3,
   engagement_full: 0.9,
+  enriched_tag_scale: 0.5,
+  era_scale: 0.5,
+  mood_scale: 0.5,
   ...over
 });