diff --git a/BUILD b/BUILD
index 9aff85c753b..34bd146cef3 100644
--- a/BUILD
+++ b/BUILD
@@ -1889,12 +1889,11 @@ grpc_cc_library(
     name = "grpc_mock_cel",
     hdrs = [
         "src/core/lib/security/authorization/mock_cel/activation.h",
-        #"src/core/lib/security/authorization/mock_cel/cel_expr_builder_factory.h",
-        #"src/core/lib/security/authorization/mock_cel/cel_expression.h",
+        "src/core/lib/security/authorization/mock_cel/cel_expr_builder_factory.h",
+        "src/core/lib/security/authorization/mock_cel/cel_expression.h",
         "src/core/lib/security/authorization/mock_cel/cel_value.h",
-        #"src/core/lib/security/authorization/mock_cel/evaluator_core.h",
-        #"src/core/lib/security/authorization/mock_cel/flat_expr_builder.h",
-        #"src/core/lib/security/authorization/mock_cel/statusor.h",
+        "src/core/lib/security/authorization/mock_cel/evaluator_core.h",
+        "src/core/lib/security/authorization/mock_cel/flat_expr_builder.h",
     ],
     language = "c++",
     deps = [
diff --git a/BUILD.gn b/BUILD.gn
index d530100358c..0acbd1b9048 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -984,7 +984,11 @@ config("grpc_config") {
         "src/core/lib/security/authorization/evaluate_args.cc",
         "src/core/lib/security/authorization/evaluate_args.h",
         "src/core/lib/security/authorization/mock_cel/activation.h",
+        "src/core/lib/security/authorization/mock_cel/cel_expr_builder_factory.h",
+        "src/core/lib/security/authorization/mock_cel/cel_expression.h",
         "src/core/lib/security/authorization/mock_cel/cel_value.h",
+        "src/core/lib/security/authorization/mock_cel/evaluator_core.h",
+        "src/core/lib/security/authorization/mock_cel/flat_expr_builder.h",
         "src/core/lib/security/context/security_context.cc",
         "src/core/lib/security/context/security_context.h",
         "src/core/lib/security/credentials/alts/alts_credentials.cc",
diff --git a/build_autogenerated.yaml b/build_autogenerated.yaml
index df6bdeed97b..33466f4c119 100644
--- a/build_autogenerated.yaml
+++ b/build_autogenerated.yaml
@@ -755,7 +755,11 @@ libs:
   - src/core/lib/security/authorization/authorization_engine.h
   - src/core/lib/security/authorization/evaluate_args.h
   - src/core/lib/security/authorization/mock_cel/activation.h
+  - src/core/lib/security/authorization/mock_cel/cel_expr_builder_factory.h
+  - src/core/lib/security/authorization/mock_cel/cel_expression.h
   - src/core/lib/security/authorization/mock_cel/cel_value.h
+  - src/core/lib/security/authorization/mock_cel/evaluator_core.h
+  - src/core/lib/security/authorization/mock_cel/flat_expr_builder.h
   - src/core/lib/security/context/security_context.h
   - src/core/lib/security/credentials/alts/alts_credentials.h
   - src/core/lib/security/credentials/alts/check_gcp_environment.h
diff --git a/gRPC-C++.podspec b/gRPC-C++.podspec
index da0642a77f0..2d2843a8809 100644
--- a/gRPC-C++.podspec
+++ b/gRPC-C++.podspec
@@ -600,7 +600,11 @@ Pod::Spec.new do |s|
                       'src/core/lib/security/authorization/authorization_engine.h',
                       'src/core/lib/security/authorization/evaluate_args.h',
                       'src/core/lib/security/authorization/mock_cel/activation.h',
+                      'src/core/lib/security/authorization/mock_cel/cel_expr_builder_factory.h',
+                      'src/core/lib/security/authorization/mock_cel/cel_expression.h',
                       'src/core/lib/security/authorization/mock_cel/cel_value.h',
+                      'src/core/lib/security/authorization/mock_cel/evaluator_core.h',
+                      'src/core/lib/security/authorization/mock_cel/flat_expr_builder.h',
                       'src/core/lib/security/context/security_context.h',
                       'src/core/lib/security/credentials/alts/alts_credentials.h',
                       'src/core/lib/security/credentials/alts/check_gcp_environment.h',
@@ -1204,7 +1208,11 @@ Pod::Spec.new do |s|
                               'src/core/lib/security/authorization/authorization_engine.h',
                               'src/core/lib/security/authorization/evaluate_args.h',
                               'src/core/lib/security/authorization/mock_cel/activation.h',
+                              'src/core/lib/security/authorization/mock_cel/cel_expr_builder_factory.h',
+                              'src/core/lib/security/authorization/mock_cel/cel_expression.h',
                               'src/core/lib/security/authorization/mock_cel/cel_value.h',
+                              'src/core/lib/security/authorization/mock_cel/evaluator_core.h',
+                              'src/core/lib/security/authorization/mock_cel/flat_expr_builder.h',
                               'src/core/lib/security/context/security_context.h',
                               'src/core/lib/security/credentials/alts/alts_credentials.h',
                               'src/core/lib/security/credentials/alts/check_gcp_environment.h',
diff --git a/gRPC-Core.podspec b/gRPC-Core.podspec
index 6a36ba9b9a6..c99259b3577 100644
--- a/gRPC-Core.podspec
+++ b/gRPC-Core.podspec
@@ -1040,7 +1040,11 @@ Pod::Spec.new do |s|
                       'src/core/lib/security/authorization/evaluate_args.cc',
                       'src/core/lib/security/authorization/evaluate_args.h',
                       'src/core/lib/security/authorization/mock_cel/activation.h',
+                      'src/core/lib/security/authorization/mock_cel/cel_expr_builder_factory.h',
+                      'src/core/lib/security/authorization/mock_cel/cel_expression.h',
                       'src/core/lib/security/authorization/mock_cel/cel_value.h',
+                      'src/core/lib/security/authorization/mock_cel/evaluator_core.h',
+                      'src/core/lib/security/authorization/mock_cel/flat_expr_builder.h',
                       'src/core/lib/security/context/security_context.cc',
                       'src/core/lib/security/context/security_context.h',
                       'src/core/lib/security/credentials/alts/alts_credentials.cc',
@@ -1733,7 +1737,11 @@ Pod::Spec.new do |s|
                               'src/core/lib/security/authorization/authorization_engine.h',
                               'src/core/lib/security/authorization/evaluate_args.h',
                               'src/core/lib/security/authorization/mock_cel/activation.h',
+                              'src/core/lib/security/authorization/mock_cel/cel_expr_builder_factory.h',
+                              'src/core/lib/security/authorization/mock_cel/cel_expression.h',
                               'src/core/lib/security/authorization/mock_cel/cel_value.h',
+                              'src/core/lib/security/authorization/mock_cel/evaluator_core.h',
+                              'src/core/lib/security/authorization/mock_cel/flat_expr_builder.h',
                               'src/core/lib/security/context/security_context.h',
                               'src/core/lib/security/credentials/alts/alts_credentials.h',
                               'src/core/lib/security/credentials/alts/check_gcp_environment.h',
diff --git a/grpc.gemspec b/grpc.gemspec
index 3652846adf1..df687b72ec7 100644
--- a/grpc.gemspec
+++ b/grpc.gemspec
@@ -957,7 +957,11 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/security/authorization/evaluate_args.cc )
   s.files += %w( src/core/lib/security/authorization/evaluate_args.h )
   s.files += %w( src/core/lib/security/authorization/mock_cel/activation.h )
+  s.files += %w( src/core/lib/security/authorization/mock_cel/cel_expr_builder_factory.h )
+  s.files += %w( src/core/lib/security/authorization/mock_cel/cel_expression.h )
   s.files += %w( src/core/lib/security/authorization/mock_cel/cel_value.h )
+  s.files += %w( src/core/lib/security/authorization/mock_cel/evaluator_core.h )
+  s.files += %w( src/core/lib/security/authorization/mock_cel/flat_expr_builder.h )
   s.files += %w( src/core/lib/security/context/security_context.cc )
   s.files += %w( src/core/lib/security/context/security_context.h )
   s.files += %w( src/core/lib/security/credentials/alts/alts_credentials.cc )
diff --git a/package.xml b/package.xml
index 75a98409381..40997492ed6 100644
--- a/package.xml
+++ b/package.xml
@@ -937,7 +937,11 @@
     <file baseinstalldir="/" name="src/core/lib/security/authorization/evaluate_args.cc" role="src" />
     <file baseinstalldir="/" name="src/core/lib/security/authorization/evaluate_args.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/security/authorization/mock_cel/activation.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/security/authorization/mock_cel/cel_expr_builder_factory.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/security/authorization/mock_cel/cel_expression.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/security/authorization/mock_cel/cel_value.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/security/authorization/mock_cel/evaluator_core.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/security/authorization/mock_cel/flat_expr_builder.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/security/context/security_context.cc" role="src" />
     <file baseinstalldir="/" name="src/core/lib/security/context/security_context.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/security/credentials/alts/alts_credentials.cc" role="src" />
diff --git a/src/core/lib/security/authorization/mock_cel/cel_expr_builder_factory.h b/src/core/lib/security/authorization/mock_cel/cel_expr_builder_factory.h
index 3f22a28d609..74f2288ceb8 100644
--- a/src/core/lib/security/authorization/mock_cel/cel_expr_builder_factory.h
+++ b/src/core/lib/security/authorization/mock_cel/cel_expr_builder_factory.h
@@ -33,7 +33,7 @@ struct InterpreterOptions {
   bool short_circuiting = true;
 };
 
-std::unique_ptr<CelExpressionBuilder> CreateCelExpressionBuilder(
+inline std::unique_ptr<CelExpressionBuilder> CreateCelExpressionBuilder(
     const InterpreterOptions& options) {
   return absl::make_unique<FlatExprBuilder>();
 }
diff --git a/src/core/lib/security/authorization/mock_cel/cel_expression.h b/src/core/lib/security/authorization/mock_cel/cel_expression.h
index bdeba67a41d..34a31a6d525 100644
--- a/src/core/lib/security/authorization/mock_cel/cel_expression.h
+++ b/src/core/lib/security/authorization/mock_cel/cel_expression.h
@@ -20,10 +20,11 @@
 #include <memory>
 #include <vector>
 
+#include "absl/status/statusor.h"
+
 #include "google/api/expr/v1alpha1/syntax.upb.h"
 #include "src/core/lib/security/authorization/mock_cel/activation.h"
 #include "src/core/lib/security/authorization/mock_cel/cel_value.h"
-#include "src/core/lib/security/authorization/mock_cel/statusor.h"
 
 namespace grpc_core {
 namespace mock_cel {
@@ -38,7 +39,7 @@ class CelExpression {
 
   // Evaluates expression and returns value.
   // activation contains bindings from parameter names to values
-  virtual StatusOr<CelValue> Evaluate(
+  virtual absl::StatusOr<CelValue> Evaluate(
       const BaseActivation& activation) const = 0;
 };
 
@@ -52,11 +53,11 @@ class CelExpressionBuilder {
 
   // Creates CelExpression object from AST tree.
   // expr specifies root of AST tree
-  virtual StatusOr<std::unique_ptr<CelExpression>> CreateExpression(
+  virtual absl::StatusOr<std::unique_ptr<CelExpression>> CreateExpression(
       const google_api_expr_v1alpha1_Expr* expr,
       const google_api_expr_v1alpha1_SourceInfo* source_info) const = 0;
 
-  virtual StatusOr<std::unique_ptr<CelExpression>> CreateExpression(
+  virtual absl::StatusOr<std::unique_ptr<CelExpression>> CreateExpression(
       const google_api_expr_v1alpha1_Expr* expr,
       const google_api_expr_v1alpha1_SourceInfo* source_info,
       std::vector<absl::Status>* warnings) const = 0;
diff --git a/src/core/lib/security/authorization/mock_cel/evaluator_core.h b/src/core/lib/security/authorization/mock_cel/evaluator_core.h
index 7ddf495baf0..9aab0d2a8e6 100644
--- a/src/core/lib/security/authorization/mock_cel/evaluator_core.h
+++ b/src/core/lib/security/authorization/mock_cel/evaluator_core.h
@@ -21,11 +21,12 @@
 #include <set>
 #include <vector>
 
+#include "absl/status/statusor.h"
+
 #include "google/api/expr/v1alpha1/syntax.upb.h"
 #include "src/core/lib/security/authorization/mock_cel/activation.h"
 #include "src/core/lib/security/authorization/mock_cel/cel_expression.h"
 #include "src/core/lib/security/authorization/mock_cel/cel_value.h"
-#include "src/core/lib/security/authorization/mock_cel/statusor.h"
 
 namespace grpc_core {
 namespace mock_cel {
@@ -33,13 +34,11 @@ namespace mock_cel {
 // This is a temporary stub implementation of CEL APIs.
 // Once gRPC imports the CEL library, this file will be removed.
 
-class ExpressionStep {
+class ExecutionPath {
  public:
-  virtual ~ExpressionStep() = default;
+  ExecutionPath() = default;
 };
 
-using ExecutionPath = std::vector<std::unique_ptr<const ExpressionStep>>;
-
 // Implementation of the CelExpression that utilizes flattening
 // of the expression tree.
 class CelExpressionFlatImpl : public CelExpression {
@@ -56,7 +55,8 @@ class CelExpressionFlatImpl : public CelExpression {
                         bool enable_unknown_function_results = false) {}
 
   // Implementation of CelExpression evaluate method.
-  StatusOr<CelValue> Evaluate(const BaseActivation& activation) const override {
+  absl::StatusOr<CelValue> Evaluate(
+      const BaseActivation& activation) const override {
     return CelValue::CreateNull();
   }
 };
diff --git a/src/core/lib/security/authorization/mock_cel/flat_expr_builder.h b/src/core/lib/security/authorization/mock_cel/flat_expr_builder.h
index 86f5a239a32..255f0031624 100644
--- a/src/core/lib/security/authorization/mock_cel/flat_expr_builder.h
+++ b/src/core/lib/security/authorization/mock_cel/flat_expr_builder.h
@@ -33,20 +33,21 @@ class FlatExprBuilder : public CelExpressionBuilder {
  public:
   FlatExprBuilder() = default;
 
-  cel_base::StatusOr<std::unique_ptr<CelExpression>> CreateExpression(
-      const google::api::expr::v1alpha1::Expr* expr,
-      const google::api::expr::v1alpha1::SourceInfo* source_info)
-      const override {
+  absl::StatusOr<std::unique_ptr<CelExpression>> CreateExpression(
+      const google_api_expr_v1alpha1_Expr* expr,
+      const google_api_expr_v1alpha1_SourceInfo* source_info) const override {
     ExecutionPath path;
-    return absl::make_unique<CelExpressionFlatImpl>(nullptr, path, 0);
+    return absl::make_unique<CelExpressionFlatImpl>(nullptr, path, 0,
+                                                    std::set<std::string>{});
   }
 
-  cel_base::StatusOr<std::unique_ptr<CelExpression>> CreateExpression(
-      const google::api::expr::v1alpha1::Expr* expr,
-      const google::api::expr::v1alpha1::SourceInfo* source_info,
+  absl::StatusOr<std::unique_ptr<CelExpression>> CreateExpression(
+      const google_api_expr_v1alpha1_Expr* expr,
+      const google_api_expr_v1alpha1_SourceInfo* source_info,
       std::vector<absl::Status>* warnings) const override {
     ExecutionPath path;
-    return absl::make_unique<CelExpressionFlatImpl>(nullptr, path, 0);
+    return absl::make_unique<CelExpressionFlatImpl>(nullptr, path, 0,
+                                                    std::set<std::string>{});
   }
 };
 
diff --git a/src/core/lib/security/authorization/mock_cel/statusor.h b/src/core/lib/security/authorization/mock_cel/statusor.h
deleted file mode 100644
index f97a8ec1229..00000000000
--- a/src/core/lib/security/authorization/mock_cel/statusor.h
+++ /dev/null
@@ -1,50 +0,0 @@
-// Copyright 2020 gRPC authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef GRPC_CORE_LIB_SECURITY_AUTHORIZATION_MOCK_CEL_STATUSOR_H
-#define GRPC_CORE_LIB_SECURITY_AUTHORIZATION_MOCK_CEL_STATUSOR_H
-
-#include <grpc/support/port_platform.h>
-
-#include <memory>
-
-#include "absl/status/status.h"
-
-namespace grpc_core {
-namespace mock_cel {
-
-// This is a temporary stub implementation of CEL APIs.
-// Once gRPC imports the CEL library, this file will be removed.
-
-template <typename T>
-class ABSL_MUST_USE_RESULT StatusOr;
-
-template <typename T>
-class StatusOr {
- public:
-  StatusOr() = default;
-
-  StatusOr(const T& value) {}
-
-  StatusOr(const absl::Status& status) {}
-
-  StatusOr(absl::Status&& status) {}
-
-  bool ok() const { return true; }
-};
-
-}  // namespace mock_cel
-}  // namespace grpc_core
-
-#endif  // GRPC_CORE_LIB_SECURITY_AUTHORIZATION_MOCK_CEL_STATUSOR_H
\ No newline at end of file
diff --git a/tools/doxygen/Doxyfile.c++.internal b/tools/doxygen/Doxyfile.c++.internal
index 90aadee82c6..791e2298921 100644
--- a/tools/doxygen/Doxyfile.c++.internal
+++ b/tools/doxygen/Doxyfile.c++.internal
@@ -1889,7 +1889,11 @@ src/core/lib/security/authorization/authorization_engine.h \
 src/core/lib/security/authorization/evaluate_args.cc \
 src/core/lib/security/authorization/evaluate_args.h \
 src/core/lib/security/authorization/mock_cel/activation.h \
+src/core/lib/security/authorization/mock_cel/cel_expr_builder_factory.h \
+src/core/lib/security/authorization/mock_cel/cel_expression.h \
 src/core/lib/security/authorization/mock_cel/cel_value.h \
+src/core/lib/security/authorization/mock_cel/evaluator_core.h \
+src/core/lib/security/authorization/mock_cel/flat_expr_builder.h \
 src/core/lib/security/context/security_context.cc \
 src/core/lib/security/context/security_context.h \
 src/core/lib/security/credentials/alts/alts_credentials.cc \
diff --git a/tools/doxygen/Doxyfile.core.internal b/tools/doxygen/Doxyfile.core.internal
index 10de1cb9e2a..8abfd99d44a 100644
--- a/tools/doxygen/Doxyfile.core.internal
+++ b/tools/doxygen/Doxyfile.core.internal
@@ -1731,7 +1731,11 @@ src/core/lib/security/authorization/authorization_engine.h \
 src/core/lib/security/authorization/evaluate_args.cc \
 src/core/lib/security/authorization/evaluate_args.h \
 src/core/lib/security/authorization/mock_cel/activation.h \
+src/core/lib/security/authorization/mock_cel/cel_expr_builder_factory.h \
+src/core/lib/security/authorization/mock_cel/cel_expression.h \
 src/core/lib/security/authorization/mock_cel/cel_value.h \
+src/core/lib/security/authorization/mock_cel/evaluator_core.h \
+src/core/lib/security/authorization/mock_cel/flat_expr_builder.h \
 src/core/lib/security/context/security_context.cc \
 src/core/lib/security/context/security_context.h \
 src/core/lib/security/credentials/alts/alts_credentials.cc \