diff --git a/redwood-compose/src/commonTest/kotlin/app/cash/redwood/compose/ChangeListenerTest.kt b/redwood-compose/src/commonTest/kotlin/app/cash/redwood/compose/ChangeListenerTest.kt
index 6da0d4945c..388d3942c5 100644
--- a/redwood-compose/src/commonTest/kotlin/app/cash/redwood/compose/ChangeListenerTest.kt
+++ b/redwood-compose/src/commonTest/kotlin/app/cash/redwood/compose/ChangeListenerTest.kt
@@ -25,7 +25,6 @@ import app.cash.redwood.lazylayout.widget.RedwoodLazyLayoutTestingWidgetFactory
 import app.cash.redwood.protocol.widget.ProtocolBridge
 import app.cash.redwood.testing.TestRedwoodComposition
 import app.cash.redwood.testing.WidgetValue
-import app.cash.redwood.ui.UiConfiguration
 import app.cash.redwood.widget.MutableListChildren
 import assertk.assertThat
 import assertk.assertions.containsExactly
@@ -42,14 +41,13 @@ import com.example.redwood.testing.widget.TestSchemaWidgetFactories
 import com.example.redwood.testing.widget.TestSchemaWidgetFactory
 import kotlin.test.Test
 import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.test.runTest
 
 class DirectChangeListenerTest : AbstractChangeListenerTest() {
   override fun <T> CoroutineScope.launchComposition(
     factories: TestSchemaWidgetFactories<WidgetValue>,
     snapshot: () -> T,
-  ) = TestRedwoodComposition(this, factories, MutableListChildren(), MutableStateFlow(UiConfiguration()), snapshot)
+  ) = TestRedwoodComposition(this, factories, MutableListChildren(), createSnapshot = snapshot)
 }
 
 class ProtocolChangeListenerTest : AbstractChangeListenerTest() {
@@ -61,7 +59,7 @@ class ProtocolChangeListenerTest : AbstractChangeListenerTest() {
     val widgetBridge = ProtocolBridge(MutableListChildren(), TestSchemaProtocolNodeFactory(factories)) {
       throw AssertionError()
     }
-    return TestRedwoodComposition(this, composeBridge.provider, composeBridge.root, MutableStateFlow(UiConfiguration())) {
+    return TestRedwoodComposition(this, composeBridge.provider, composeBridge.root) {
       composeBridge.getChangesOrNull()?.let { changes ->
         widgetBridge.sendChanges(changes)
       }
diff --git a/redwood-lazylayout-compose/src/commonTest/kotlin/app/cash/redwood/lazylayout/compose/LazyListTest.kt b/redwood-lazylayout-compose/src/commonTest/kotlin/app/cash/redwood/lazylayout/compose/LazyListTest.kt
index f0a1b6309f..d9c97a55fe 100644
--- a/redwood-lazylayout-compose/src/commonTest/kotlin/app/cash/redwood/lazylayout/compose/LazyListTest.kt
+++ b/redwood-lazylayout-compose/src/commonTest/kotlin/app/cash/redwood/lazylayout/compose/LazyListTest.kt
@@ -29,7 +29,6 @@ import app.cash.redwood.lazylayout.widget.WindowedLazyList
 import app.cash.redwood.testing.TestRedwoodComposition
 import app.cash.redwood.testing.WidgetValue
 import app.cash.redwood.ui.Margin
-import app.cash.redwood.ui.UiConfiguration
 import app.cash.redwood.ui.dp
 import app.cash.redwood.widget.MutableListChildren
 import assertk.assertThat
@@ -40,7 +39,6 @@ import com.example.redwood.testing.widget.TestSchemaWidgetFactories
 import com.example.redwood.testing.widget.TextValue
 import kotlin.test.Test
 import kotlinx.coroutines.coroutineScope
-import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.test.runTest
 
 class LazyListTest {
@@ -148,7 +146,6 @@ private suspend fun <R> TestSchemaTester(
       this,
       factories,
       container,
-      MutableStateFlow(UiConfiguration()),
     ) {
       container.map { it.value }
     }
diff --git a/redwood-protocol-compose/src/commonTest/kotlin/app/cash/redwood/protocol/compose/ProtocolTest.kt b/redwood-protocol-compose/src/commonTest/kotlin/app/cash/redwood/protocol/compose/ProtocolTest.kt
index 097dcaee17..b0babf3aa3 100644
--- a/redwood-protocol-compose/src/commonTest/kotlin/app/cash/redwood/protocol/compose/ProtocolTest.kt
+++ b/redwood-protocol-compose/src/commonTest/kotlin/app/cash/redwood/protocol/compose/ProtocolTest.kt
@@ -237,7 +237,6 @@ class ProtocolTest {
       scope = backgroundScope,
       provider = bridge.provider,
       container = bridge.root,
-      uiConfigurations = MutableStateFlow(UiConfiguration()),
     ) {
       bridge.getChangesOrNull() ?: emptyList()
     }
diff --git a/redwood-testing/src/commonMain/kotlin/app/cash/redwood/testing/TestRedwoodComposition.kt b/redwood-testing/src/commonMain/kotlin/app/cash/redwood/testing/TestRedwoodComposition.kt
index 93c5a114e9..bedc07a14a 100644
--- a/redwood-testing/src/commonMain/kotlin/app/cash/redwood/testing/TestRedwoodComposition.kt
+++ b/redwood-testing/src/commonMain/kotlin/app/cash/redwood/testing/TestRedwoodComposition.kt
@@ -18,6 +18,7 @@ package app.cash.redwood.testing
 import androidx.compose.runtime.BroadcastFrameClock
 import androidx.compose.runtime.Composable
 import app.cash.redwood.compose.RedwoodComposition
+import app.cash.redwood.compose.current
 import app.cash.redwood.ui.Cancellable
 import app.cash.redwood.ui.OnBackPressedCallback
 import app.cash.redwood.ui.OnBackPressedDispatcher
@@ -30,7 +31,7 @@ import kotlinx.coroutines.Job
 import kotlinx.coroutines.TimeoutCancellationException
 import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.delay
-import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.plus
 import kotlinx.coroutines.withTimeout
@@ -42,10 +43,10 @@ public fun <W : Any, S> TestRedwoodComposition(
   scope: CoroutineScope,
   provider: Widget.Provider<W>,
   container: Widget.Children<W>,
-  uiConfigurations: StateFlow<UiConfiguration>,
+  initialUiConfiguration: UiConfiguration = UiConfiguration(),
   createSnapshot: () -> S,
 ): TestRedwoodComposition<S> {
-  return RealTestRedwoodComposition(scope, provider, container, uiConfigurations, createSnapshot)
+  return RealTestRedwoodComposition(scope, provider, container, initialUiConfiguration, createSnapshot)
 }
 
 public interface TestRedwoodComposition<S> : RedwoodComposition {
@@ -55,6 +56,12 @@ public interface TestRedwoodComposition<S> : RedwoodComposition {
    * @throws TimeoutCancellationException if no new snapshot is produced before [timeout].
    */
   public suspend fun awaitSnapshot(timeout: Duration = 1.seconds): S
+
+  /**
+   * The mutable [UiConfiguration] instance bound to [UiConfiguration.current][current]
+   * inside the composition.
+   */
+  public val uiConfigurations: MutableStateFlow<UiConfiguration>
 }
 
 /** Performs Redwood composition strictly for testing. */
@@ -62,7 +69,7 @@ private class RealTestRedwoodComposition<W : Any, S>(
   scope: CoroutineScope,
   provider: Widget.Provider<W>,
   container: Widget.Children<W>,
-  uiConfigurations: StateFlow<UiConfiguration>,
+  initialUiConfiguration: UiConfiguration,
   createSnapshot: () -> S,
 ) : TestRedwoodComposition<S> {
   /** Emit frames manually in [sendFrames]. */
@@ -73,6 +80,8 @@ private class RealTestRedwoodComposition<W : Any, S>(
   /** Channel with the most recent snapshot, if any. */
   private val snapshots = Channel<S>(Channel.CONFLATED)
 
+  override val uiConfigurations = MutableStateFlow(initialUiConfiguration)
+
   private val composition = RedwoodComposition(
     scope = scope + clock,
     container = container,
diff --git a/redwood-testing/src/commonTest/kotlin/app/cash/redwood/testing/ViewTreesTest.kt b/redwood-testing/src/commonTest/kotlin/app/cash/redwood/testing/ViewTreesTest.kt
index aaf74f3c27..44a3164dc1 100644
--- a/redwood-testing/src/commonTest/kotlin/app/cash/redwood/testing/ViewTreesTest.kt
+++ b/redwood-testing/src/commonTest/kotlin/app/cash/redwood/testing/ViewTreesTest.kt
@@ -18,6 +18,7 @@ package app.cash.redwood.testing
 import androidx.compose.runtime.BroadcastFrameClock
 import androidx.compose.runtime.Composable
 import app.cash.redwood.RedwoodCodegenApi
+import app.cash.redwood.compose.current
 import app.cash.redwood.layout.widget.RedwoodLayoutTestingWidgetFactory
 import app.cash.redwood.lazylayout.widget.RedwoodLazyLayoutTestingWidgetFactory
 import app.cash.redwood.protocol.Change
@@ -37,6 +38,7 @@ import app.cash.redwood.ui.OnBackPressedDispatcher
 import app.cash.redwood.ui.UiConfiguration
 import app.cash.redwood.widget.MutableListChildren
 import assertk.assertThat
+import assertk.assertions.containsExactly
 import assertk.assertions.isEqualTo
 import com.example.redwood.testing.compose.TestRow
 import com.example.redwood.testing.compose.TestSchemaProtocolBridge
@@ -45,6 +47,7 @@ import com.example.redwood.testing.widget.TestSchemaProtocolNodeFactory
 import com.example.redwood.testing.widget.TestSchemaTester
 import com.example.redwood.testing.widget.TestSchemaTestingWidgetFactory
 import com.example.redwood.testing.widget.TestSchemaWidgetFactories
+import com.example.redwood.testing.widget.TextValue
 import kotlin.test.Test
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.plus
@@ -142,4 +145,20 @@ class ViewTreesTest {
 
     assertThat(widgetContainer.map { it.value }).isEqualTo(snapshot)
   }
+
+  @Test fun uiConfigurationWorks() = runTest {
+    TestSchemaTester {
+      setContent {
+        Text("Dark: ${UiConfiguration.current.darkMode}")
+      }
+
+      val first = awaitSnapshot()
+      assertThat(first).containsExactly(TextValue(text = "Dark: false"))
+
+      uiConfigurations.value = UiConfiguration(darkMode = true)
+
+      val second = awaitSnapshot()
+      assertThat(second).containsExactly(TextValue(text = "Dark: true"))
+    }
+  }
 }
diff --git a/redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/testingGeneration.kt b/redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/testingGeneration.kt
index d7f878f8bc..2a0b7a567d 100644
--- a/redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/testingGeneration.kt
+++ b/redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/testingGeneration.kt
@@ -50,7 +50,7 @@ suspend fun <R> ExampleTester(
     RedwoodLayout = RedwoodLayoutTestingWidgetFactory(),
   )
   val container = MutableListChildren<WidgetValue>()
-  val tester = TestRedwoodComposition(this, factories, container, MutableStateFlow(UiConfiguration())) {
+  val tester = TestRedwoodComposition(this, factories, container) {
     container.map { it.value }
   }
   try {
@@ -86,7 +86,7 @@ internal fun generateTester(schemaSet: SchemaSet): FileSpec {
         }
         .addCode("⇤)\n")
         .addStatement("val container = %T<%T>()", RedwoodWidget.MutableListChildren, RedwoodTesting.WidgetValue)
-        .beginControlFlow("val tester = %T(this, factories, container, %M(%T()))", RedwoodTesting.TestRedwoodComposition, KotlinxCoroutines.MutableStateFlow, RedwoodRuntime.UiConfiguration)
+        .beginControlFlow("val tester = %T(this, factories, container)", RedwoodTesting.TestRedwoodComposition)
         .addStatement("container.map { it.value }")
         .endControlFlow()
         .beginControlFlow("try")
diff --git a/redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/types.kt b/redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/types.kt
index b1e508c95d..7fa4a66905 100644
--- a/redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/types.kt
+++ b/redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/types.kt
@@ -67,10 +67,6 @@ internal object Redwood {
     .build()
 }
 
-internal object RedwoodRuntime {
-  val UiConfiguration = ClassName("app.cash.redwood.ui", "UiConfiguration")
-}
-
 internal object RedwoodTesting {
   val TestRedwoodComposition = ClassName("app.cash.redwood.testing", "TestRedwoodComposition")
   val WidgetValue = ClassName("app.cash.redwood.testing", "WidgetValue")
@@ -144,5 +140,4 @@ internal object KotlinxSerialization {
 
 internal object KotlinxCoroutines {
   val coroutineScope = MemberName("kotlinx.coroutines", "coroutineScope")
-  val MutableStateFlow = MemberName("kotlinx.coroutines.flow", "MutableStateFlow")
 }