diff --git a/runtime/src/main/java/dev/cel/runtime/BUILD.bazel b/runtime/src/main/java/dev/cel/runtime/BUILD.bazel
index e5df8250b..4a5f6dcc7 100644
--- a/runtime/src/main/java/dev/cel/runtime/BUILD.bazel
+++ b/runtime/src/main/java/dev/cel/runtime/BUILD.bazel
@@ -118,9 +118,9 @@ java_library(
     tags = [
     ],
     deps = [
-        ":base",
         ":evaluation_exception",
         ":evaluation_exception_builder",
+        ":function_overload",
         ":resolved_overload",
         ":resolved_overload_internal",
         "//:auto_value",
@@ -138,9 +138,9 @@ cel_android_library(
     srcs = DISPATCHER_SOURCES,
     visibility = ["//visibility:private"],
     deps = [
-        ":base_android",
         ":evaluation_exception",
         ":evaluation_exception_builder",
+        ":function_overload_android",
         ":function_resolver_android",
         ":resolved_overload_android",
         ":resolved_overload_internal_android",
@@ -725,7 +725,6 @@ java_library(
     ],
     deps = [
         ":function_overload",
-        "//common/annotations",
         "@maven//:com_google_errorprone_error_prone_annotations",
         "@maven//:com_google_guava_guava",
     ],
@@ -738,7 +737,6 @@ cel_android_library(
     ],
     deps = [
         ":function_overload_android",
-        "//common/annotations",
         "@maven//:com_google_errorprone_error_prone_annotations",
         "@maven_android//:com_google_guava_guava",
     ],
diff --git a/runtime/src/main/java/dev/cel/runtime/CelFunctionBinding.java b/runtime/src/main/java/dev/cel/runtime/CelFunctionBinding.java
index 8fe2b8a2e..79b0f3f54 100644
--- a/runtime/src/main/java/dev/cel/runtime/CelFunctionBinding.java
+++ b/runtime/src/main/java/dev/cel/runtime/CelFunctionBinding.java
@@ -16,7 +16,6 @@
 
 import com.google.common.collect.ImmutableList;
 import com.google.errorprone.annotations.Immutable;
-import dev.cel.common.annotations.Internal;
 
 /**
  * Binding consisting of an overload id, a Java-native argument signature, and an overload
@@ -36,7 +35,7 @@
  *
  * <p>Examples: string_startsWith_string, mathMax_list, lessThan_money_money
  */
-@Internal
+
 @Immutable
 public interface CelFunctionBinding {
   String getOverloadId();
@@ -45,6 +44,8 @@ public interface CelFunctionBinding {
 
   CelFunctionOverload getDefinition();
 
+  boolean isStrict();
+
   /** Create a unary function binding from the {@code overloadId}, {@code arg}, and {@code impl}. */
   @SuppressWarnings("unchecked")
   static <T> CelFunctionBinding from(
@@ -66,6 +67,7 @@ static <T1, T2> CelFunctionBinding from(
   /** Create a function binding from the {@code overloadId}, {@code argTypes}, and {@code impl}. */
   static CelFunctionBinding from(
       String overloadId, Iterable<Class<?>> argTypes, CelFunctionOverload impl) {
-    return new FunctionBindingImpl(overloadId, ImmutableList.copyOf(argTypes), impl);
+    return new FunctionBindingImpl(
+        overloadId, ImmutableList.copyOf(argTypes), impl, /* isStrict= */ true);
   }
 }
diff --git a/runtime/src/main/java/dev/cel/runtime/CelLateFunctionBindings.java b/runtime/src/main/java/dev/cel/runtime/CelLateFunctionBindings.java
index 282ef1eb9..6762feec0 100644
--- a/runtime/src/main/java/dev/cel/runtime/CelLateFunctionBindings.java
+++ b/runtime/src/main/java/dev/cel/runtime/CelLateFunctionBindings.java
@@ -58,6 +58,7 @@ private static ResolvedOverload createResolvedOverload(CelFunctionBinding bindin
     return CelResolvedOverload.of(
         binding.getOverloadId(),
         (args) -> binding.getDefinition().apply(args),
+        binding.isStrict(),
         binding.getArgTypes());
   }
 }
diff --git a/runtime/src/main/java/dev/cel/runtime/CelResolvedOverload.java b/runtime/src/main/java/dev/cel/runtime/CelResolvedOverload.java
index 9725315cc..26f86a459 100644
--- a/runtime/src/main/java/dev/cel/runtime/CelResolvedOverload.java
+++ b/runtime/src/main/java/dev/cel/runtime/CelResolvedOverload.java
@@ -35,6 +35,21 @@ abstract class CelResolvedOverload implements ResolvedOverload {
   @Override
   public abstract ImmutableList<Class<?>> getParameterTypes();
 
+  /* Denotes whether an overload is strict.
+   *
+   * <p>A strict function will not be invoked if any of its arguments are an error or unknown value.
+   * The runtime automatically propagates the error or unknown instead.
+   *
+   * <p>A non-strict function will be invoked even if its arguments contain errors or unknowns. The
+   * function's implementation is then responsible for handling these values. This is primarily used
+   * for short-circuiting logical operators (e.g., `||`, `&&`) and comprehension's
+   * internal @not_strictly_false function.
+   *
+   * <p>In a vast majority of cases, this should be set to true.
+   */
+  @Override
+  public abstract boolean isStrict();
+
   /** The function definition. */
   @Override
   public abstract CelFunctionOverload getDefinition();
@@ -43,16 +58,22 @@ abstract class CelResolvedOverload implements ResolvedOverload {
    * Creates a new resolved overload from the given overload id, parameter types, and definition.
    */
   public static CelResolvedOverload of(
-      String overloadId, CelFunctionOverload definition, Class<?>... parameterTypes) {
-    return of(overloadId, definition, ImmutableList.copyOf(parameterTypes));
+      String overloadId,
+      CelFunctionOverload definition,
+      boolean isStrict,
+      Class<?>... parameterTypes) {
+    return of(overloadId, definition, isStrict, ImmutableList.copyOf(parameterTypes));
   }
 
   /**
    * Creates a new resolved overload from the given overload id, parameter types, and definition.
    */
   public static CelResolvedOverload of(
-      String overloadId, CelFunctionOverload definition, List<Class<?>> parameterTypes) {
+      String overloadId,
+      CelFunctionOverload definition,
+      boolean isStrict,
+      List<Class<?>> parameterTypes) {
     return new AutoValue_CelResolvedOverload(
-        overloadId, ImmutableList.copyOf(parameterTypes), definition);
+        overloadId, ImmutableList.copyOf(parameterTypes), isStrict, definition);
   }
 }
diff --git a/runtime/src/main/java/dev/cel/runtime/CelRuntimeLegacyImpl.java b/runtime/src/main/java/dev/cel/runtime/CelRuntimeLegacyImpl.java
index 2947445d1..4f58d44db 100644
--- a/runtime/src/main/java/dev/cel/runtime/CelRuntimeLegacyImpl.java
+++ b/runtime/src/main/java/dev/cel/runtime/CelRuntimeLegacyImpl.java
@@ -293,7 +293,7 @@ public CelRuntimeLegacyImpl build() {
           .forEach(
               (String overloadId, CelFunctionBinding func) ->
                   dispatcher.add(
-                      overloadId, func.getArgTypes(), (args) -> func.getDefinition().apply(args)));
+                      overloadId, func.getArgTypes(), func.isStrict(), func.getDefinition()));
 
       RuntimeTypeProvider runtimeTypeProvider;
 
diff --git a/runtime/src/main/java/dev/cel/runtime/DefaultDispatcher.java b/runtime/src/main/java/dev/cel/runtime/DefaultDispatcher.java
index c4c27005e..6228dd253 100644
--- a/runtime/src/main/java/dev/cel/runtime/DefaultDispatcher.java
+++ b/runtime/src/main/java/dev/cel/runtime/DefaultDispatcher.java
@@ -32,7 +32,7 @@
  * <p>Should be final, do not mock; mocking {@link Dispatcher} instead.
  */
 @ThreadSafe
-final class DefaultDispatcher implements Dispatcher, Registrar {
+final class DefaultDispatcher implements Dispatcher {
   public static DefaultDispatcher create() {
     return new DefaultDispatcher();
   }
@@ -40,32 +40,9 @@ public static DefaultDispatcher create() {
   @GuardedBy("this")
   private final Map<String, ResolvedOverload> overloads = new HashMap<>();
 
-  @Override
-  @SuppressWarnings("unchecked")
-  public synchronized <T> void add(
-      String overloadId, Class<T> argType, final Registrar.UnaryFunction<T> function) {
-    overloads.put(
-        overloadId,
-        CelResolvedOverload.of(overloadId, args -> function.apply((T) args[0]), argType));
-  }
-
-  @Override
-  @SuppressWarnings("unchecked")
-  public synchronized <T1, T2> void add(
-      String overloadId,
-      Class<T1> argType1,
-      Class<T2> argType2,
-      final Registrar.BinaryFunction<T1, T2> function) {
-    overloads.put(
-        overloadId,
-        CelResolvedOverload.of(
-            overloadId, args -> function.apply((T1) args[0], (T2) args[1]), argType1, argType2));
-  }
-
-  @Override
   public synchronized void add(
-      String overloadId, List<Class<?>> argTypes, Registrar.Function function) {
-    overloads.put(overloadId, CelResolvedOverload.of(overloadId, function, argTypes));
+      String overloadId, List<Class<?>> argTypes, boolean isStrict, CelFunctionOverload overload) {
+    overloads.put(overloadId, CelResolvedOverload.of(overloadId, overload, isStrict, argTypes));
   }
 
   @Override
diff --git a/runtime/src/main/java/dev/cel/runtime/FunctionBindingImpl.java b/runtime/src/main/java/dev/cel/runtime/FunctionBindingImpl.java
index 501608571..b554ce41a 100644
--- a/runtime/src/main/java/dev/cel/runtime/FunctionBindingImpl.java
+++ b/runtime/src/main/java/dev/cel/runtime/FunctionBindingImpl.java
@@ -26,6 +26,8 @@ final class FunctionBindingImpl implements CelFunctionBinding {
 
   private final CelFunctionOverload definition;
 
+  private final boolean isStrict;
+
   @Override
   public String getOverloadId() {
     return overloadId;
@@ -41,10 +43,19 @@ public CelFunctionOverload getDefinition() {
     return definition;
   }
 
+  @Override
+  public boolean isStrict() {
+    return isStrict;
+  }
+
   FunctionBindingImpl(
-      String overloadId, ImmutableList<Class<?>> argTypes, CelFunctionOverload definition) {
+      String overloadId,
+      ImmutableList<Class<?>> argTypes,
+      CelFunctionOverload definition,
+      boolean isStrict) {
     this.overloadId = overloadId;
     this.argTypes = argTypes;
     this.definition = definition;
+    this.isStrict = isStrict;
   }
 }
diff --git a/runtime/src/main/java/dev/cel/runtime/LiteRuntimeImpl.java b/runtime/src/main/java/dev/cel/runtime/LiteRuntimeImpl.java
index 152c96160..aba73aed4 100644
--- a/runtime/src/main/java/dev/cel/runtime/LiteRuntimeImpl.java
+++ b/runtime/src/main/java/dev/cel/runtime/LiteRuntimeImpl.java
@@ -182,7 +182,10 @@ public CelLiteRuntime build() {
           .forEach(
               (String overloadId, CelFunctionBinding func) ->
                   dispatcher.add(
-                      overloadId, func.getArgTypes(), (args) -> func.getDefinition().apply(args)));
+                      overloadId,
+                      func.getArgTypes(),
+                      func.isStrict(),
+                      (args) -> func.getDefinition().apply(args)));
 
       Interpreter interpreter =
           new DefaultInterpreter(
diff --git a/runtime/src/main/java/dev/cel/runtime/Registrar.java b/runtime/src/main/java/dev/cel/runtime/Registrar.java
index 12dbe6cb3..467a7c426 100644
--- a/runtime/src/main/java/dev/cel/runtime/Registrar.java
+++ b/runtime/src/main/java/dev/cel/runtime/Registrar.java
@@ -15,15 +15,15 @@
 package dev.cel.runtime;
 
 import com.google.errorprone.annotations.Immutable;
-import dev.cel.common.annotations.Internal;
 import java.util.List;
 
 /**
  * An object which registers the functions that a {@link Dispatcher} calls.
  *
- * <p>CEL Library Internals. Do Not Use.
+ * @deprecated Do not use. This interface exists solely for legacy async stack compatibility
+ *     reasons.
  */
-@Internal
+@Deprecated
 public interface Registrar {
 
   /** Interface describing the general signature of all CEL custom function implementations. */
diff --git a/runtime/src/main/java/dev/cel/runtime/ResolvedOverload.java b/runtime/src/main/java/dev/cel/runtime/ResolvedOverload.java
index bc7544199..d0b4d2f77 100644
--- a/runtime/src/main/java/dev/cel/runtime/ResolvedOverload.java
+++ b/runtime/src/main/java/dev/cel/runtime/ResolvedOverload.java
@@ -35,6 +35,21 @@ interface ResolvedOverload {
   /** The function definition. */
   CelFunctionOverload getDefinition();
 
+  /**
+   * Denotes whether an overload is strict.
+   *
+   * <p>A strict function will not be invoked if any of its arguments are an error or unknown value.
+   * The runtime automatically propagates the error or unknown instead.
+   *
+   * <p>A non-strict function will be invoked even if its arguments contain errors or unknowns. The
+   * function's implementation is then responsible for handling these values. This is primarily used
+   * for short-circuiting logical operators (e.g., `||`, `&&`) and comprehension's
+   * internal @not_strictly_false function.
+   *
+   * <p>In a vast majority of cases, a function should be kept strict.
+   */
+  boolean isStrict();
+
   /**
    * Returns true if the overload's expected argument types match the types of the given arguments.
    */
diff --git a/runtime/src/test/java/dev/cel/runtime/CelResolvedOverloadTest.java b/runtime/src/test/java/dev/cel/runtime/CelResolvedOverloadTest.java
index 2c81b89d4..0fdc4f65d 100644
--- a/runtime/src/test/java/dev/cel/runtime/CelResolvedOverloadTest.java
+++ b/runtime/src/test/java/dev/cel/runtime/CelResolvedOverloadTest.java
@@ -32,6 +32,7 @@ CelResolvedOverload getIncrementIntOverload() {
           Long arg = (Long) args[0];
           return arg + 1;
         },
+        /* isStrict= */ true,
         Long.class);
   }
 
@@ -43,14 +44,15 @@ public void canHandle_matchingTypes_returnsTrue() {
   @Test
   public void canHandle_nullMessageType_returnsTrue() {
     CelResolvedOverload overload =
-        CelResolvedOverload.of("identity", (args) -> args[0], TestAllTypes.class);
+        CelResolvedOverload.of(
+            "identity", (args) -> args[0], /* isStrict= */ true, TestAllTypes.class);
     assertThat(overload.canHandle(new Object[] {null})).isTrue();
   }
 
   @Test
   public void canHandle_nullPrimitive_returnsFalse() {
     CelResolvedOverload overload =
-        CelResolvedOverload.of("identity", (args) -> args[0], Long.class);
+        CelResolvedOverload.of("identity", (args) -> args[0], /* isStrict= */ true, Long.class);
     assertThat(overload.canHandle(new Object[] {null})).isFalse();
   }
 
diff --git a/runtime/src/test/java/dev/cel/runtime/DefaultDispatcherTest.java b/runtime/src/test/java/dev/cel/runtime/DefaultDispatcherTest.java
index 03eba51ce..fb6831201 100644
--- a/runtime/src/test/java/dev/cel/runtime/DefaultDispatcherTest.java
+++ b/runtime/src/test/java/dev/cel/runtime/DefaultDispatcherTest.java
@@ -35,9 +35,13 @@ public final class DefaultDispatcherTest {
   public void setup() {
     overloads = new HashMap<>();
     overloads.put(
-        "overload_1", CelResolvedOverload.of("overload_1", args -> (Long) args[0] + 1, Long.class));
+        "overload_1",
+        CelResolvedOverload.of(
+            "overload_1", args -> (Long) args[0] + 1, /* isStrict= */ true, Long.class));
     overloads.put(
-        "overload_2", CelResolvedOverload.of("overload_2", args -> (Long) args[0] + 2, Long.class));
+        "overload_2",
+        CelResolvedOverload.of(
+            "overload_2", args -> (Long) args[0] + 2, /* isStrict= */ true, Long.class));
   }
 
   @Test
diff --git a/runtime/src/test/java/dev/cel/runtime/DefaultInterpreterTest.java b/runtime/src/test/java/dev/cel/runtime/DefaultInterpreterTest.java
index 4f3501d41..e9ac6b5a3 100644
--- a/runtime/src/test/java/dev/cel/runtime/DefaultInterpreterTest.java
+++ b/runtime/src/test/java/dev/cel/runtime/DefaultInterpreterTest.java
@@ -17,6 +17,7 @@
 import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.assertThrows;
 
+import com.google.common.collect.ImmutableList;
 import com.google.testing.junit.testparameterinjector.TestParameterInjector;
 import dev.cel.common.CelAbstractSyntaxTree;
 import dev.cel.common.CelFunctionDecl;
@@ -74,7 +75,11 @@ public Object adapt(String messageName, Object message) {
         };
     CelAbstractSyntaxTree ast = celCompiler.compile("[1].all(x, [2].all(y, error()))").getAst();
     DefaultDispatcher dispatcher = DefaultDispatcher.create();
-    dispatcher.add("error", long.class, (args) -> new IllegalArgumentException("Always throws"));
+    dispatcher.add(
+        "error",
+        ImmutableList.of(long.class),
+        /* isStrict= */ true,
+        (args) -> new IllegalArgumentException("Always throws"));
     DefaultInterpreter defaultInterpreter =
         new DefaultInterpreter(new TypeResolver(), emptyProvider, dispatcher, CelOptions.DEFAULT);
     DefaultInterpretable interpretable =