diff --git a/merlin-framework-processor/src/main/java/gov/nasa/jpl/aerie/merlin/processor/generator/MissionModelGenerator.java b/merlin-framework-processor/src/main/java/gov/nasa/jpl/aerie/merlin/processor/generator/MissionModelGenerator.java
index be17603c33..08af87e754 100644
--- a/merlin-framework-processor/src/main/java/gov/nasa/jpl/aerie/merlin/processor/generator/MissionModelGenerator.java
+++ b/merlin-framework-processor/src/main/java/gov/nasa/jpl/aerie/merlin/processor/generator/MissionModelGenerator.java
@@ -808,12 +808,14 @@ public Optional<JavaFile> generateActivityMapper(final MissionModelRecord missio
                         .map(effectModel -> CodeBlock
                             .builder()
                             .add(
-                                "return $T.$L(() -> {$>\n$L$<});\n",
+                                "return $T.$L(() -> $T.$L(() -> {$>\n$L$<}));\n",
                                 ModelActions.class,
                                 switch (effectModel.executor()) {
                                   case Threaded -> "threaded";
                                   case Replaying -> "replaying";
                                 },
+                                ModelActions.class,
+                                "scoped",
                                 effectModel.returnType()
                                     .map(returnType -> CodeBlock
                                         .builder()
@@ -835,6 +837,7 @@ public Optional<JavaFile> generateActivityMapper(final MissionModelRecord missio
                             .add(
                                 "return executor -> scheduler -> {$>\n$L$<};\n",
                                 CodeBlock.builder()
+                                    .addStatement("scheduler.pushSpan()")
                                     .addStatement("scheduler.emit($L, this.$L)", "activity", "inputTopic")
                                     .addStatement("scheduler.emit($T.UNIT, this.$L)", Unit.class, "outputTopic")
                                     .addStatement("return $T.completed($T.UNIT)", TaskStatus.class, Unit.class)
diff --git a/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/Context.java b/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/Context.java
index 6738237a37..65a457d1b4 100644
--- a/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/Context.java
+++ b/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/Context.java
@@ -31,6 +31,8 @@ enum ContextType { Initializing, Reacting, Querying }
 
   void spawn(TaskFactory<?> task);
   <Return> void call(TaskFactory<Return> task);
+  void pushSpan();
+  void popSpan();
 
   void delay(Duration duration);
   void waitUntil(Condition condition);
diff --git a/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/InitializationContext.java b/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/InitializationContext.java
index 9615830a69..5529a6dd6d 100644
--- a/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/InitializationContext.java
+++ b/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/InitializationContext.java
@@ -61,6 +61,16 @@ public <Return> void call(final TaskFactory<Return> task) {
     throw new IllegalStateException("Cannot yield during initialization");
   }
 
+  @Override
+  public void pushSpan() {
+    // Do nothing.
+  }
+
+  @Override
+  public void popSpan() {
+    // Do nothing.
+  }
+
   @Override
   public void delay(final Duration duration) {
     throw new IllegalStateException("Cannot yield during initialization");
diff --git a/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/ModelActions.java b/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/ModelActions.java
index 1c9019f328..bdbbabd3db 100644
--- a/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/ModelActions.java
+++ b/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/ModelActions.java
@@ -36,6 +36,22 @@ public static TaskFactory<Unit> replaying(final Runnable task) {
     });
   }
 
+  public static <T> T scoped(final Supplier<T> block) {
+    context.get().pushSpan();
+    try {
+      return block.get();
+    } finally {
+      context.get().popSpan();
+    }
+  }
+
+  public static void scoped(final Runnable block) {
+    scoped(() -> {
+      block.run();
+      return Unit.UNIT;
+    });
+  }
+
 
   public static <T> void emit(final T event, final Topic<T> topic) {
     context.get().emit(event, topic);
diff --git a/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/QueryContext.java b/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/QueryContext.java
index 2425a9ab77..e2c0bf169f 100644
--- a/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/QueryContext.java
+++ b/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/QueryContext.java
@@ -52,6 +52,16 @@ public <Return> void call(final TaskFactory<Return> task) {
     throw new IllegalStateException("Cannot schedule tasks in a query-only context");
   }
 
+  @Override
+  public void pushSpan() {
+    // Do nothing.
+  }
+
+  @Override
+  public void popSpan() {
+    // Do nothing.
+  }
+
   @Override
   public void delay(final Duration duration) {
     throw new IllegalStateException("Cannot yield in a query-only context");
diff --git a/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/ReplayingReactionContext.java b/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/ReplayingReactionContext.java
index e9998ff256..e6e8d5bbfb 100644
--- a/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/ReplayingReactionContext.java
+++ b/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/ReplayingReactionContext.java
@@ -78,6 +78,20 @@ public <T> void call(final TaskFactory<T> task) {
     });
   }
 
+  @Override
+  public void pushSpan() {
+    this.memory.doOnce(() -> {
+      this.scheduler.pushSpan();
+    });
+  }
+
+  @Override
+  public void popSpan() {
+    this.memory.doOnce(() -> {
+      this.scheduler.popSpan();
+    });
+  }
+
   @Override
   public void delay(final Duration duration) {
     this.memory.doOnce(() -> {
diff --git a/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/ThreadedReactionContext.java b/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/ThreadedReactionContext.java
index 3edd568d9e..0a4984bda0 100644
--- a/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/ThreadedReactionContext.java
+++ b/merlin-framework/src/main/java/gov/nasa/jpl/aerie/merlin/framework/ThreadedReactionContext.java
@@ -63,6 +63,16 @@ public <T> void call(final TaskFactory<T> task) {
     this.scheduler = this.handle.call(task);
   }
 
+  @Override
+  public void pushSpan() {
+    this.scheduler.pushSpan();
+  }
+
+  @Override
+  public void popSpan() {
+    this.scheduler.popSpan();
+  }
+
   @Override
   public void delay(final Duration duration) {
     this.scheduler = null;  // Relinquish the current scheduler before yielding, in case an exception is thrown.