diff --git a/proto/dev/cel/expr/conformance/BUILD.bazel b/proto/dev/cel/expr/conformance/BUILD.bazel
index c6f88d93..0587971f 100644
--- a/proto/dev/cel/expr/conformance/BUILD.bazel
+++ b/proto/dev/cel/expr/conformance/BUILD.bazel
@@ -5,9 +5,11 @@ package(default_visibility = ["//visibility:public"])
 ##############################################################################
 
 proto_library(
-    name = "conformance_service_proto",
+    name = "conformance_proto",
     srcs = [
         "conformance_service.proto",
+        "envcheck.proto",
+        "simple.proto",
     ],
     strip_import_prefix = "/proto",
     deps = [
@@ -16,20 +18,77 @@ proto_library(
     ],
 )
 
+proto_library(
+    name = "conformance_service_proto",
+    srcs = ["conformance_service.proto"],
+    strip_import_prefix = "/proto",
+    deps = [
+        "//proto/dev/cel/expr:checked_proto",
+        "//proto/dev/cel/expr:eval_proto",
+        "//proto/dev/cel/expr:syntax_proto",
+        "@com_google_googleapis//google/rpc:status_proto",
+    ],
+)
+
+proto_library(
+    name = "envcheck_proto",
+    srcs = ["envcheck.proto"],
+    strip_import_prefix = "/proto",
+    deps = [
+        "//proto/dev/cel/expr:checked_proto",
+    ],
+)
+
+proto_library(
+    name = "simple_proto",
+    srcs = ["simple.proto"],
+    strip_import_prefix = "/proto",
+    deps = [
+        "//proto/dev/cel/expr:checked_proto",
+        "//proto/dev/cel/expr:eval_proto",
+        "//proto/dev/cel/expr:value_proto",
+    ],
+)
+
 ##############################################################################
 # Java
 ##############################################################################
+java_proto_library(
+    name = "conformance_java_proto",
+    deps = [":conformance_proto"],
+)
+
 java_proto_library(
     name = "conformance_service_java_proto",
     deps = [":conformance_service_proto"],
 )
 
+java_proto_library(
+    name = "envcheck_java_proto",
+    deps = [":envcheck_proto"],
+)
+
+java_proto_library(
+    name = "simple_java_proto",
+    deps = [":simple_proto"],
+)
+
 ###############################################################################
 ## Go
 ###############################################################################
 
 load("@io_bazel_rules_go//proto:def.bzl", "go_proto_library")
 
+go_proto_library(
+    name = "conformance_go_proto",
+    importpath = "dev.cel/expr/conformance",
+    protos = [":conformance_proto"],
+    deps = [
+        "//proto/dev/cel/expr:expr_go_proto",
+        "//proto/dev/cel/expr:google_rpc_status_go_proto",
+    ],
+)
+
 go_proto_library(
     name = "conformance_service_go_proto",
     importpath = "dev.cel/expr/conformance",
@@ -40,6 +99,24 @@ go_proto_library(
     ],
 )
 
+go_proto_library(
+    name = "envcheck_go_proto",
+    importpath = "dev.cel/expr/conformance",
+    protos = [":envcheck_proto"],
+    deps = [
+        "//proto/dev/cel/expr:expr_go_proto",
+    ],
+)
+
+go_proto_library(
+    name = "simple_go_proto",
+    importpath = "dev.cel/expr/conformance",
+    protos = [":simple_proto"],
+    deps = [
+        "//proto/dev/cel/expr:expr_go_proto",
+    ],
+)
+
 ###############################################################################
 ## C++
 ###############################################################################
@@ -48,3 +125,13 @@ cc_proto_library(
     name = "conformance_service_cc_proto",
     deps = [":conformance_service_proto"],
 )
+
+cc_proto_library(
+    name = "envcheck_cc_proto",
+    deps = [":envcheck_proto"],
+)
+
+cc_proto_library(
+    name = "simple_cc_proto",
+    deps = [":simple_proto"],
+)
diff --git a/proto/dev/cel/expr/conformance/envcheck.proto b/proto/dev/cel/expr/conformance/envcheck.proto
new file mode 100644
index 00000000..1caa5ea0
--- /dev/null
+++ b/proto/dev/cel/expr/conformance/envcheck.proto
@@ -0,0 +1,37 @@
+// Copyright 2023 Google LLC
+//
+// 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.
+
+// Tests for runtime support of standard functions.
+
+syntax = "proto3";
+
+package dev.cel.expr.conformance;
+
+import "dev/cel/expr/checked.proto";
+
+option cc_enable_arenas = true;
+option go_package = "dev.cel/expr/conformance";
+option java_multiple_files = true;
+option java_outer_classname = "EnvcheckProto";
+option java_package = "dev.cel.expr.conformance";
+
+// The format of a standard environment, i.e. a collection of declarations
+// for the checker.
+message Env {
+  // Required.  The name of the environment.
+  string name = 1;
+
+  // The declarations in this environment.
+  repeated dev.cel.expr.Decl decl = 2;
+}
diff --git a/proto/dev/cel/expr/conformance/simple.proto b/proto/dev/cel/expr/conformance/simple.proto
new file mode 100644
index 00000000..1c42759e
--- /dev/null
+++ b/proto/dev/cel/expr/conformance/simple.proto
@@ -0,0 +1,124 @@
+// Copyright 2023 Google LLC
+//
+// 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.
+
+// Simple end-to-end conformance tests.
+
+syntax = "proto3";
+
+package dev.cel.expr.conformance;
+
+import "dev/cel/expr/checked.proto";
+import "dev/cel/expr/eval.proto";
+import "dev/cel/expr/value.proto";
+
+option cc_enable_arenas = true;
+option go_package = "dev.cel/expr/conformance";
+option java_multiple_files = true;
+option java_outer_classname = "SimpleProto";
+option java_package = "dev.cel.expr.conformance";
+
+// The format of a simple test file, expected to be stored in text format.
+// A file is the unit of granularity for selecting conformance tests,
+// so tests of optional features should be segregated into separate files.
+message SimpleTestFile {
+  // Required.  The name of the file.  Should match the filename.
+  string name = 1;
+
+  // A description of the file.
+  string description = 2;
+
+  // The contained sections.
+  repeated SimpleTestSection section = 3;
+}
+
+// A collection of related SimpleTests.
+//
+// The section is the unit of organization within a test file, and should
+// guide where new tests are added.
+message SimpleTestSection {
+  // Required.  The name of the section.
+  string name = 1;
+
+  // A description of the section.
+  string description = 2;
+
+  // The contained tests.
+  repeated SimpleTest test = 3;
+}
+
+// A test which should run the given CEL program through parsing,
+// optionally through checking, then evaluation, with the results
+// of the pipeline validated by the given result matcher.
+message SimpleTest {
+  // Required.  The name of the test, which should be unique in the test file.
+  string name = 1;
+
+  // A description of the test.
+  string description = 2;
+
+  // Required.  The text of the CEL expression.
+  string expr = 3;
+
+  // Disables all macro expansion in parsing.
+  bool disable_macros = 4;
+
+  // Disables the check phase.
+  bool disable_check = 5;
+
+  // The type environment to use for the check phase.
+  repeated dev.cel.expr.Decl type_env = 6;
+
+  // The container for name resolution.
+  string container = 13;
+
+  // Variable bindings to use for the eval phase.
+  map<string, dev.cel.expr.ExprValue> bindings = 7;
+
+  // An unspecified result defaults to a matcher for the true boolean value.
+  oneof result_matcher {
+    // A normal value, which must match the evaluation result exactly
+    // via value equality semantics.  This coincides with proto equality,
+    // except for:
+    // *   maps are order-agnostic.
+    // *   a floating point NaN should match any NaN.
+    dev.cel.expr.Value value = 8;
+
+    // Matches error evaluation results.
+    dev.cel.expr.ErrorSet eval_error = 9;
+
+    // Matches one of several error results.
+    // (Using explicit message since oneof can't handle repeated.)
+    ErrorSetMatcher any_eval_errors = 10;
+
+    // Matches unknown evaluation results.
+    dev.cel.expr.UnknownSet unknown = 11;
+
+    // Matches one of several unknown results.
+    // (Using explicit message since oneof can't handle repeated.)
+    UnknownSetMatcher any_unknowns = 12;
+  }
+  // Next is 14.
+}
+
+// Matches error results from Eval.
+message ErrorSetMatcher {
+  // Success if we match any of these sets.
+  repeated dev.cel.expr.ErrorSet errors = 1;
+}
+
+// Matches unknown results from Eval.
+message UnknownSetMatcher {
+  // Success if we match any of these sets.
+  repeated dev.cel.expr.UnknownSet unknowns = 1;
+}