diff --git a/.azure-pipelines/pipelines.yml b/.azure-pipelines/pipelines.yml
index e5f2904cfb54..6bc20230bafe 100644
--- a/.azure-pipelines/pipelines.yml
+++ b/.azure-pipelines/pipelines.yml
@@ -244,6 +244,8 @@ stages:
       matrix:
         api:
           CI_TARGET: "bazel.api"
+        api_compat:
+          CI_TARGET: "bazel.api_compat"
         gcc:
           CI_TARGET: "bazel.gcc"
         clang_tidy:
diff --git a/api/BUILD b/api/BUILD
index d61c9e486b81..7ac026f5d296 100644
--- a/api/BUILD
+++ b/api/BUILD
@@ -254,3 +254,11 @@ proto_library(
         ":v3_protos",
     ],
 )
+
+filegroup(
+    name = "proto_breaking_change_detector_buf_config",
+    srcs = [
+        "buf.yaml",
+    ],
+    visibility = ["//visibility:public"],
+)
diff --git a/api/bazel/repository_locations.bzl b/api/bazel/repository_locations.bzl
index 49d7997f15a5..be1e9c9789e4 100644
--- a/api/bazel/repository_locations.bzl
+++ b/api/bazel/repository_locations.bzl
@@ -122,11 +122,11 @@ REPOSITORY_LOCATIONS_SPEC = dict(
         project_name = "buf",
         project_desc = "A new way of working with Protocol Buffers.",  # Used for breaking change detection in API protobufs
         project_url = "https://buf.build",
-        version = "0.48.2",
-        sha256 = "ee0ea6c4a7bbb016d79b056905c0a1f018e7c5e47b37038c993a77b1bc732c0d",
+        version = "0.53.0",
+        sha256 = "888bb52d358e34a8d6a57ecff426bed896bdf478ad13c78a70a9e1a9a2d75715",
         strip_prefix = "buf",
         urls = ["https://github.com/bufbuild/buf/releases/download/v{version}/buf-Linux-x86_64.tar.gz"],
-        release_date = "2021-07-30",
+        release_date = "2021-08-25",
         use_category = ["api"],
         tags = ["manual"],
     ),
diff --git a/api/buf.lock b/api/buf.lock
new file mode 100644
index 000000000000..046331375ce0
--- /dev/null
+++ b/api/buf.lock
@@ -0,0 +1,52 @@
+# Generated by buf. DO NOT EDIT.
+version: v1
+deps:
+  - remote: buf.build
+    owner: beta
+    repository: opencensus
+    branch: main
+    commit: 5f5f8259293649d68707d2e5b6285748
+    digest: b1-myYwcdM0Xu05qIwhiy4eWEcARYUuZZ1vTbYvrrHu1mU=
+    create_time: 2021-03-03T20:50:42.079743Z
+  - remote: buf.build
+    owner: beta
+    repository: opentelemetry
+    branch: main
+    commit: 549da630ffe24b53be3983fcee3bb346
+    digest: b1-HVAvWKH61BF6TdZSbHRhrD2SUuC0V7uAlZgCRimGPLI=
+    create_time: 2021-08-09T14:24:57.923964Z
+  - remote: buf.build
+    owner: beta
+    repository: prometheus
+    branch: main
+    commit: a91b42d18a994cd4b07b37f365f87cf9
+    digest: b1-uKmv58fyoNwJI855qg7UEagfdyUl6XNPsFAdDoi57f4=
+    create_time: 2021-06-23T20:16:58.410272Z
+  - remote: buf.build
+    owner: beta
+    repository: protoc-gen-validate
+    branch: main
+    commit: 82388a0a0cb04e98a203f95dfed5e84b
+    digest: b1-lYgUMN58PxyCwvfQoopp40AJ-oHHjWXAzksF7v9U-U4=
+    create_time: 2021-06-21T22:00:30.152545Z
+  - remote: buf.build
+    owner: beta
+    repository: xds
+    branch: main
+    commit: 45f850b92541434cbde4aece01bc7d53
+    digest: b1-QZUL5DC6-nVgMMlajH_hlImwghg5HjRsqlEAOl0dZgI=
+    create_time: 2021-08-09T14:37:06.872899Z
+  - remote: buf.build
+    owner: gogo
+    repository: protobuf
+    branch: main
+    commit: 4df00b267f944190a229ce3695781e99
+    digest: b1-sjLgsg7CzrkOrIjBDh3s-l0aMjE6oqTj85-OsoopKAw=
+    create_time: 2021-08-10T00:14:28.345069Z
+  - remote: buf.build
+    owner: googleapis
+    repository: googleapis
+    branch: main
+    commit: d1a849b8f8304950832335723096e954
+    digest: b1-zJkwX0YeOp1Wa0Jaj_RqMLa2-oEzePH6PJEK8aaMeI4=
+    create_time: 2021-08-26T15:07:19.652533Z
diff --git a/tools/api_proto_breaking_change_detector/buf.yaml b/api/buf.yaml
similarity index 53%
rename from tools/api_proto_breaking_change_detector/buf.yaml
rename to api/buf.yaml
index 2f3631072e7c..781f01f972ce 100644
--- a/tools/api_proto_breaking_change_detector/buf.yaml
+++ b/api/buf.yaml
@@ -1,5 +1,13 @@
 version: v1beta1
+deps:
+    - buf.build/googleapis/googleapis
+    - buf.build/beta/opencensus
+    - buf.build/beta/prometheus
+    - buf.build/beta/opentelemetry
+    - buf.build/gogo/protobuf
+    - buf.build/beta/xds
 breaking:
+  ignore_unstable_packages: true
   use:
     - FIELD_SAME_ONEOF
     - FIELD_SAME_JSON_NAME
@@ -7,7 +15,5 @@ breaking:
     - FIELD_SAME_TYPE
     - FIELD_SAME_LABEL
     - FILE_SAME_PACKAGE
-
-    # needed for allowing removal/reserving of fields
     - FIELD_NO_DELETE_UNLESS_NUMBER_RESERVED
     - FIELD_NO_DELETE_UNLESS_NAME_RESERVED
diff --git a/bazel/api_binding.bzl b/bazel/api_binding.bzl
index 56d7c95f08a8..362e1803a1ef 100644
--- a/bazel/api_binding.bzl
+++ b/bazel/api_binding.bzl
@@ -9,6 +9,7 @@ def _default_envoy_api_impl(ctx):
         "tools",
         "versioning",
         "contrib",
+        "buf.yaml",
     ]
     for d in api_dirs:
         ctx.symlink(ctx.path(ctx.attr.envoy_root).dirname.get_child(ctx.attr.reldir).get_child(d), d)
diff --git a/ci/do_ci.sh b/ci/do_ci.sh
index 4f8e196fd256..106c3924923e 100755
--- a/ci/do_ci.sh
+++ b/ci/do_ci.sh
@@ -375,6 +375,16 @@ elif [[ "$CI_TARGET" == "bazel.api" ]]; then
   # We use custom BAZEL_BUILD_OPTIONS here; the API booster isn't capable of working with libc++ yet.
   BAZEL_BUILD_OPTIONS="${BAZEL_BUILD_OPTIONS[*]}" python3.8 "${ENVOY_SRCDIR}"/tools/api_boost/api_boost_test.py
   exit 0
+elif [[ "$CI_TARGET" == "bazel.api_compat" ]]; then
+  echo "Building buf..."
+  bazel build @com_github_bufbuild_buf//:buf
+  BUF_PATH=$(realpath "bazel-source/external/com_github_bufbuild_buf/bin/buf")
+  echo "Checking API for breaking changes to protobuf backwards compatibility..."
+  BASE_BRANCH_REF=$("${ENVOY_SRCDIR}"/tools/git/last_github_commit.sh)
+  COMMIT_TITLE=$(git log -n 1 --pretty='format:%C(auto)%h (%s, %ad)' "${BASE_BRANCH_REF}")
+  echo -e "\tUsing base commit ${COMMIT_TITLE}"
+  "${ENVOY_SRCDIR}"/tools/api_proto_breaking_change_detector/detector_ci.sh "${BUF_PATH}" "${BASE_BRANCH_REF}"
+  exit 0
 elif [[ "$CI_TARGET" == "bazel.coverage" || "$CI_TARGET" == "bazel.fuzz_coverage" ]]; then
   setup_clang_toolchain
   echo "${CI_TARGET} build with tests ${COVERAGE_TEST_TARGETS[*]}"
diff --git a/generated_api_shadow/BUILD b/generated_api_shadow/BUILD
index d61c9e486b81..7ac026f5d296 100644
--- a/generated_api_shadow/BUILD
+++ b/generated_api_shadow/BUILD
@@ -254,3 +254,11 @@ proto_library(
         ":v3_protos",
     ],
 )
+
+filegroup(
+    name = "proto_breaking_change_detector_buf_config",
+    srcs = [
+        "buf.yaml",
+    ],
+    visibility = ["//visibility:public"],
+)
diff --git a/generated_api_shadow/bazel/repository_locations.bzl b/generated_api_shadow/bazel/repository_locations.bzl
index 49d7997f15a5..be1e9c9789e4 100644
--- a/generated_api_shadow/bazel/repository_locations.bzl
+++ b/generated_api_shadow/bazel/repository_locations.bzl
@@ -122,11 +122,11 @@ REPOSITORY_LOCATIONS_SPEC = dict(
         project_name = "buf",
         project_desc = "A new way of working with Protocol Buffers.",  # Used for breaking change detection in API protobufs
         project_url = "https://buf.build",
-        version = "0.48.2",
-        sha256 = "ee0ea6c4a7bbb016d79b056905c0a1f018e7c5e47b37038c993a77b1bc732c0d",
+        version = "0.53.0",
+        sha256 = "888bb52d358e34a8d6a57ecff426bed896bdf478ad13c78a70a9e1a9a2d75715",
         strip_prefix = "buf",
         urls = ["https://github.com/bufbuild/buf/releases/download/v{version}/buf-Linux-x86_64.tar.gz"],
-        release_date = "2021-07-30",
+        release_date = "2021-08-25",
         use_category = ["api"],
         tags = ["manual"],
     ),
diff --git a/tools/api_proto_breaking_change_detector/BUILD b/tools/api_proto_breaking_change_detector/BUILD
index 7eec29a9772b..bce76c323d36 100644
--- a/tools/api_proto_breaking_change_detector/BUILD
+++ b/tools/api_proto_breaking_change_detector/BUILD
@@ -1,35 +1,56 @@
-load("@rules_python//python:defs.bzl", "py_binary", "py_test")
+load("@rules_python//python:defs.bzl", "py_binary", "py_library", "py_test")
 
 licenses(["notice"])  # Apache 2
 
 py_binary(
-    name = "proto_breaking_change_detector",
-    srcs = ["detector.py"],
+    name = "detector",
+    srcs = [
+        "detector.py",
+    ],
     data = [
-        ":buf.lock",
-        ":buf.yaml",
         "@com_github_bufbuild_buf//:buf",
+        "@envoy_api_canonical//:proto_breaking_change_detector_buf_config",
     ],
     main = "detector.py",
     tags = ["manual"],
     deps = [
+        ":buf_utils",
+        ":detector_errors",
         "//tools:run_command",
     ],
 )
 
+py_library(
+    name = "buf_utils",
+    srcs = [
+        "buf_utils.py",
+    ],
+    deps = [
+        ":detector_errors",
+        "//tools/base:utils",
+    ],
+)
+
+py_library(
+    name = "detector_errors",
+    srcs = [
+        "detector_errors.py",
+    ],
+)
+
 py_test(
-    name = "proto_breaking_change_detector_test",
+    name = "detector_test",
     srcs = ["detector_test.py"],
     data = [
         "//tools/testdata/api_proto_breaking_change_detector:proto_breaking_change_detector_testdata",
-        "@com_github_bufbuild_buf//:buf",
     ],
     main = "detector_test.py",
     python_version = "PY3",
     srcs_version = "PY3",
     tags = ["manual"],
     deps = [
-        ":proto_breaking_change_detector",
+        ":detector",
+        "//tools:run_command",
         "@rules_python//python/runfiles",
     ],
 )
diff --git a/tools/api_proto_breaking_change_detector/buf.lock b/tools/api_proto_breaking_change_detector/buf.lock
deleted file mode 100644
index d33cf64e43a5..000000000000
--- a/tools/api_proto_breaking_change_detector/buf.lock
+++ /dev/null
@@ -1,45 +0,0 @@
-# Generated by buf. DO NOT EDIT.
-version: v1
-deps:
-  - remote: buf.build
-    owner: beta
-    repository: googleapis
-    branch: main
-    commit: 1c473ad9220a49bca9320f4cc690eba5
-    digest: b1-unlhrcI3tnJd0JEGuOb692LZ_tY_gCGq6mK1bgCn1Pg=
-    create_time: 2021-06-23T20:16:47.788079Z
-  - remote: buf.build
-    owner: beta
-    repository: opencensus
-    branch: main
-    commit: 5f5f8259293649d68707d2e5b6285748
-    digest: b1-myYwcdM0Xu05qIwhiy4eWEcARYUuZZ1vTbYvrrHu1mU=
-    create_time: 2021-03-03T20:50:42.079743Z
-  - remote: buf.build
-    owner: beta
-    repository: opentelemetry
-    branch: main
-    commit: ee82722300c04a618e1c9a2373ce2958
-    digest: b1-MwMH-u3ygagogGt6GnJMsqSyxDL-6RKCThaBQRdT_28=
-    create_time: 2021-06-23T20:17:01.385563Z
-  - remote: buf.build
-    owner: beta
-    repository: prometheus
-    branch: main
-    commit: a91b42d18a994cd4b07b37f365f87cf9
-    digest: b1-uKmv58fyoNwJI855qg7UEagfdyUl6XNPsFAdDoi57f4=
-    create_time: 2021-06-23T20:16:58.410272Z
-  - remote: buf.build
-    owner: beta
-    repository: protoc-gen-validate
-    branch: main
-    commit: 3aa3a142febe4d198171026cddadb18b
-    digest: b1-MkZlf7zGl1xvJCsBhk-Kh46tvCHpRNpGNUOtryA9-ng=
-    create_time: 2021-03-30T19:57:01.168017Z
-  - remote: buf.build
-    owner: beta
-    repository: udpa
-    branch: main
-    commit: 64457162aab743c5a695a8cccbd93d8d
-    digest: b1-15-sblwZI7jDyUli6FyJsBTy8dRe6mHTA2B2VTcIm4g=
-    create_time: 2021-03-30T19:57:09.877302Z
diff --git a/tools/api_proto_breaking_change_detector/buf_utils.py b/tools/api_proto_breaking_change_detector/buf_utils.py
new file mode 100644
index 000000000000..1c279e84a49c
--- /dev/null
+++ b/tools/api_proto_breaking_change_detector/buf_utils.py
@@ -0,0 +1,105 @@
+from pathlib import Path
+from typing import List, Union, Tuple
+
+from detector_errors import ChangeDetectorError, ChangeDetectorInitializeError
+from tools.base.utils import cd_and_return
+from tools.run_command import run_command
+
+
+def _generate_buf_args(target_path, config_file_loc, additional_args):
+    buf_args = []
+
+    # buf requires relative pathing for roots
+    target_relative = Path(target_path).absolute().relative_to(Path.cwd().absolute())
+
+    # buf does not accept . as a root; if we are already in the target dir, no need for a --path arg
+    if str(target_relative) != ".":
+        buf_args.extend(["--path", str(target_relative)])
+
+    if config_file_loc:
+        buf_args.extend(["--config", str(config_file_loc)])
+
+    buf_args.extend(additional_args or [])
+
+    return buf_args
+
+
+def _cd_into_config_parent(config_file_loc):
+    config_parent = Path(config_file_loc).parent if config_file_loc else Path.cwd()
+    return cd_and_return(config_parent)
+
+
+def pull_buf_deps(
+        buf_path: Union[str, Path],
+        target_path: Union[str, Path],
+        config_file_loc: Union[str, Path] = None,
+        additional_args: List[str] = None) -> None:
+    """Updates buf.lock file and downloads any BSR dependencies specified in buf.yaml
+
+    Note that in order for dependency downloading to trigger, `buf build`
+    must be invoked, so `target_path` must contain valid proto syntax.
+
+    Args:
+        buf_path {Union[str, Path]} -- path to buf binary to use
+        target_path {Union[str, Path]} -- path to directory containing protos to run buf on
+
+        config_file_loc {Union[str, Path]} -- absolute path to buf.yaml configuration file (if not provided, uses default buf configuration)
+        additional_args {List[str]} -- additional arguments passed into the buf binary invocations
+
+    Raises:
+        ChangeDetectorInitializeError: if buf encounters an error while attempting to update the buf.lock file or build afterward
+    """
+    with _cd_into_config_parent(config_file_loc):
+        buf_args = _generate_buf_args(target_path, config_file_loc, additional_args)
+
+        update_code, _, update_err = run_command(f'{buf_path} mod update')
+        # for some reason buf prints out the "downloading..." lines on stderr
+        if update_code != 0:
+            raise ChangeDetectorInitializeError(
+                f"Error running `buf mod update`: exit status code {update_code} | stderr: {''.join(update_err)}"
+            )
+        if not Path.cwd().joinpath("buf.lock").exists():
+            raise ChangeDetectorInitializeError(
+                "buf mod update did not generate a buf.lock file (silent error... incorrect config?)"
+            )
+
+        run_command(' '.join([f'{buf_path} build', *buf_args]))
+
+
+def check_breaking(
+        buf_path: Union[str, Path],
+        target_path: Union[str, Path],
+        git_ref: str,
+        git_path: Union[str, Path],
+        config_file_loc: Union[str, Path] = None,
+        additional_args: List[str] = None,
+        subdir: str = None) -> Tuple[int, List[str], List[str]]:
+    """Runs `buf breaking` to check for breaking changes between the `target_path` protos and the provided initial state
+
+    Args:
+        buf_path {Union[str, Path]} -- path to buf binary to use
+        target_path {Union[str, Path]} -- path to directory containing protos to check for breaking changes
+        git_ref {str} -- git reference to use for the initial state of the protos (typically a commit hash)
+        git_path {Union[str, Path]} -- absolute path to .git folder for the repository of interest
+
+        subdir {str} -- subdirectory within git repository from which to search for .proto files (default: None, e.g. stay in root)
+        config_file_loc {Union[str, Path]} -- absolute path to buf.yaml configuration file (if not provided, uses default buf configuration)
+        additional_args {List[str]} -- additional arguments passed into the buf binary invocations
+
+    Returns:
+        Tuple[int, List[str], List[str]] -- tuple of (exit status code, stdout, stderr) as provided by run_command. Note stdout/stderr are provided as string lists
+    """
+    with _cd_into_config_parent(config_file_loc):
+        if not Path(git_path).exists():
+            raise ChangeDetectorError(f'path to .git folder {git_path} does not exist')
+
+        buf_args = _generate_buf_args(target_path, config_file_loc, additional_args)
+
+        initial_state_input = f'{git_path}#ref={git_ref}'
+
+        if subdir:
+            initial_state_input += f',subdir={subdir}'
+
+        final_code, final_out, final_err = run_command(
+            ' '.join([buf_path, f"breaking --against {initial_state_input}", *buf_args]))
+        return final_code, final_out, final_err
diff --git a/tools/api_proto_breaking_change_detector/detector.py b/tools/api_proto_breaking_change_detector/detector.py
index 88fe99ed193a..c5a66be94214 100644
--- a/tools/api_proto_breaking_change_detector/detector.py
+++ b/tools/api_proto_breaking_change_detector/detector.py
@@ -13,40 +13,22 @@
 The tool is currently implemented with buf (https://buf.build/)
 """
 
-import tempfile
-from rules_python.python.runfiles import runfiles
-from tools.run_command import run_command
-from shutil import copyfile
 from pathlib import Path
-import os
 from typing import List
 
+from buf_utils import check_breaking, pull_buf_deps
+from detector_errors import ChangeDetectorError
+
 
 class ProtoBreakingChangeDetector(object):
     """Abstract breaking change detector interface"""
 
-    def __init__(self, path_to_before: str, path_to_after: str) -> None:
-        """Initialize the configuration of the breaking change detector
-
-        This function sets up any necessary config without actually
-        running the detector against any proto files.
-
-        Takes in a single protobuf as 2 files, in a ``before`` state
-        and an ``after`` state, and checks if the ``after`` state
-        violates any breaking change rules.
-
-        Args:
-            path_to_before {str} -- absolute path to the .proto file in the before state
-            path_to_after {str} -- absolute path to the .proto file in the after state
-        """
-        pass
-
     def run_detector(self) -> None:
         """Run the breaking change detector to detect rule violations
 
         This method should populate the detector's internal data such
-        that `is_breaking` and `lock_file_changed` do not require any
-        additional invocations to the breaking change detector.
+        that `is_breaking` does not require any additional invocations
+        to the breaking change detector.
         """
         pass
 
@@ -54,108 +36,98 @@ def is_breaking(self) -> bool:
         """Return True if breaking changes were detected in the given protos"""
         pass
 
-    def lock_file_changed(self) -> bool:
-        """Return True if the detector state file changed after being run
-
-        This function assumes that the detector uses a lock file to
-        compare "before" and "after" states of protobufs, which is
-        admittedly an implementation detail. It is mostly used for
-        testing, to ensure that the breaking change detector is
-        checking all of the protobuf features we are interested in.
-        """
+    def get_breaking_changes(self) -> List[str]:
+        """Return a list of strings containing breaking changes output by the tool"""
         pass
 
 
-class ChangeDetectorError(Exception):
-    pass
-
-
-class ChangeDetectorInitializeError(ChangeDetectorError):
-    pass
-
-
-BUF_STATE_FILE = "tmp.json"
-
-
 class BufWrapper(ProtoBreakingChangeDetector):
     """Breaking change detector implemented with buf"""
 
     def __init__(
             self,
-            path_to_before: str,
-            path_to_after: str,
+            path_to_changed_dir: str,
+            git_ref: str,
+            git_path: str,
+            subdir: str = None,
+            buf_path: str = None,
+            config_file_loc: str = None,
             additional_args: List[str] = None) -> None:
-        if not Path(path_to_before).is_file():
-            raise ValueError(f"path_to_before {path_to_before} does not exist")
-
-        if not Path(path_to_after).is_file():
-            raise ValueError(f"path_to_after {path_to_after} does not exist")
+        """Initialize the configuration of buf
 
-        self._path_to_before = path_to_before
-        self._path_to_after = path_to_after
-        self._additional_args = additional_args
-
-    def run_detector(self) -> None:
-        # buf requires protobuf files to be in a subdirectory of the yaml file
-        with tempfile.TemporaryDirectory(prefix=str(Path(".").absolute()) + os.sep) as temp_dir:
-            buf_path = runfiles.Create().Rlocation("com_github_bufbuild_buf/bin/buf")
-
-            buf_config_loc = Path(".", "tools", "api_proto_breaking_change_detector")
-
-            yaml_file_loc = Path(".", "buf.yaml")
-            copyfile(Path(buf_config_loc, "buf.yaml"), yaml_file_loc)
-
-            target = Path(temp_dir, f"{Path(self._path_to_before).stem}.proto")
-
-            buf_args = [
-                "--path",
-                # buf requires relative pathing for roots
-                str(target.relative_to(Path(".").absolute())),
-                "--config",
-                str(yaml_file_loc),
-            ]
-            buf_args.extend(self._additional_args or [])
-
-            copyfile(self._path_to_before, target)
-
-            lock_location = Path(temp_dir, BUF_STATE_FILE)
+        This function sets up any necessary config without actually
+        running buf against any proto files.
 
-            initial_code, initial_out, initial_err = run_command(
-                ' '.join([buf_path, f"build -o {lock_location}", *buf_args]))
-            initial_out, initial_err = ''.join(initial_out), ''.join(initial_err)
+        BufWrapper takes a path to a directory containing proto files
+        as input, and it checks if these proto files break any changes
+        from a given initial state.
 
-            if initial_code != 0 or len(initial_out) > 0 or len(initial_err) > 0:
-                raise ChangeDetectorInitializeError(
-                    f"Unexpected error during init:\n\tExit Status Code: {initial_code}\n\tstdout: {initial_out}\n\t stderr: {initial_err}\n"
-                )
+        The initial state is input as a git ref. The constructor expects
+        a git ref string, as well as an absolute path to a .git folder
+        for the repository.
 
-            with open(lock_location, "r") as f:
-                self._initial_lock = f.readlines()
+        Args:
+            path_to_changed_dir {str} -- absolute path to a directory containing proto files in the after state
+            buf_path {str} -- path to the buf binary (default: "buf")
+            git_ref {str} -- git reference to use for the initial state of the protos (typically a commit hash)
+            git_path {str} -- absolute path to .git folder for the repository of interest
+
+            subdir {str} -- subdirectory within git repository from which to search for .proto files (default: None, e.g. stay in root)
+            additional_args {List[str]} -- additional arguments passed into the buf binary invocations
+            config_file_loc {str} -- absolute path to buf.yaml configuration file (if not provided, uses default buf configuration)
+        """
+        if not Path(path_to_changed_dir).is_dir():
+            raise ValueError(f"path_to_changed_dir {path_to_changed_dir} is not a valid directory")
 
-            copyfile(self._path_to_after, target)
+        if Path.cwd() not in Path(path_to_changed_dir).parents:
+            raise ValueError(
+                f"path_to_changed_dir {path_to_changed_dir} must be a subdirectory of the cwd ({ Path.cwd() })"
+            )
 
-            final_code, final_out, final_err = run_command(
-                ' '.join([buf_path, f"breaking --against {lock_location}", *buf_args]))
-            final_out, final_err = ''.join(final_out), ''.join(final_err)
+        if not Path(git_path).exists():
+            raise ChangeDetectorError(f'path to .git folder {git_path} does not exist')
 
-            if len(final_out) == len(final_err) == final_code == 0:
-                _, _, _ = run_command(' '.join([buf_path, f"build -o {lock_location}", *buf_args]))
-            with open(lock_location, "r") as f:
-                self._final_lock = f.readlines()
+        self._path_to_changed_dir = path_to_changed_dir
+        self._additional_args = additional_args
+        self._buf_path = buf_path or "buf"
+        self._config_file_loc = config_file_loc
+        self._git_ref = git_ref
+        self._git_path = git_path
+        self._subdir = subdir
+        self._final_result = None
+
+        pull_buf_deps(
+            self._buf_path,
+            self._path_to_changed_dir,
+            config_file_loc=self._config_file_loc,
+            additional_args=self._additional_args)
 
-            self._initial_result = initial_code, initial_out, initial_err
-            self._final_result = final_code, final_out, final_err
+    def run_detector(self) -> None:
+        self._final_result = check_breaking(
+            self._buf_path,
+            self._path_to_changed_dir,
+            git_ref=self._git_ref,
+            git_path=self._git_path,
+            subdir=self._subdir,
+            config_file_loc=self._config_file_loc,
+            additional_args=self._additional_args)
 
     def is_breaking(self) -> bool:
+        if not self._final_result:
+            raise ChangeDetectorError("Must invoke run_detector() before checking if is_breaking()")
+
         final_code, final_out, final_err = self._final_result
+        final_out, final_err = '\n'.join(final_out), '\n'.join(final_err)
+
+        if final_err != "":
+            raise ChangeDetectorError(f"Error from buf: {final_err}")
 
         if final_code != 0:
             return True
-        if final_out != "" or "Failure" in final_out:
-            return True
-        if final_err != "" or "Failure" in final_err:
+        if final_out != "":
             return True
         return False
 
-    def lock_file_changed(self) -> bool:
-        return any(before != after for before, after in zip(self._initial_lock, self._final_lock))
+    def get_breaking_changes(self) -> List[str]:
+        _, final_out, _ = self._final_result
+        return filter(lambda x: len(x) > 0, final_out) if self.is_breaking() else []
diff --git a/tools/api_proto_breaking_change_detector/detector_ci.py b/tools/api_proto_breaking_change_detector/detector_ci.py
new file mode 100755
index 000000000000..84278d6d4b07
--- /dev/null
+++ b/tools/api_proto_breaking_change_detector/detector_ci.py
@@ -0,0 +1,44 @@
+#!/usr/bin/env python3
+
+import argparse
+import sys
+from pathlib import Path
+
+from detector import BufWrapper
+
+API_DIR = Path("api").resolve()
+GIT_PATH = Path.cwd().joinpath(".git")
+CONFIG_FILE_LOC = Path(API_DIR, "buf.yaml")
+
+
+def detect_breaking_changes_git(path_to_buf, ref):
+    """Returns True if breaking changes were detected in the api folder"""
+    detector = BufWrapper(
+        API_DIR,
+        buf_path=path_to_buf,
+        config_file_loc=CONFIG_FILE_LOC,
+        git_ref=ref,
+        git_path=GIT_PATH,
+        subdir="api")
+    detector.run_detector()
+    breaking = detector.is_breaking()
+
+    if breaking:
+        print('Breaking changes detected in api protobufs:')
+        for i, breaking_change in enumerate(detector.get_breaking_changes()):
+            print(f'\t{i}: {breaking_change}')
+        print("ERROR: non-backwards-compatible changes detected in api protobufs.")
+    return breaking
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(
+        description=
+        'Tool to detect breaking changes in api protobufs and enforce backwards compatibility.')
+    parser.add_argument('buf_path', type=str, help='path to buf binary')
+    parser.add_argument(
+        'git_ref', type=str, help='git reference to check against for breaking changes')
+    args = parser.parse_args()
+
+    exit_status = detect_breaking_changes_git(args.buf_path, args.git_ref)
+    sys.exit(exit_status)
diff --git a/tools/api_proto_breaking_change_detector/detector_ci.sh b/tools/api_proto_breaking_change_detector/detector_ci.sh
new file mode 100755
index 000000000000..7f0ec3271e1e
--- /dev/null
+++ b/tools/api_proto_breaking_change_detector/detector_ci.sh
@@ -0,0 +1,9 @@
+#!/bin/bash
+
+tools="$(dirname "$(dirname "$(realpath "$0")")")"
+root=$(realpath "$tools/..")
+
+cd "$root" || exit 1
+# to satisfy dependency on run_command (as done in tools/code_format/check_format_test_helper.sh)
+export PYTHONPATH="$root"
+./tools/api_proto_breaking_change_detector/detector_ci.py "$@"
diff --git a/tools/api_proto_breaking_change_detector/detector_errors.py b/tools/api_proto_breaking_change_detector/detector_errors.py
new file mode 100644
index 000000000000..724bcfd52fc7
--- /dev/null
+++ b/tools/api_proto_breaking_change_detector/detector_errors.py
@@ -0,0 +1,6 @@
+class ChangeDetectorError(Exception):
+    pass
+
+
+class ChangeDetectorInitializeError(ChangeDetectorError):
+    pass
diff --git a/tools/api_proto_breaking_change_detector/detector_test.py b/tools/api_proto_breaking_change_detector/detector_test.py
index 874ad4b788bc..1566bf2d500d 100644
--- a/tools/api_proto_breaking_change_detector/detector_test.py
+++ b/tools/api_proto_breaking_change_detector/detector_test.py
@@ -7,32 +7,24 @@
 and ensure that tool behavior is consistent across dependency updates.
 """
 
-from pathlib import Path
+import tempfile
 import unittest
+from pathlib import Path
+from shutil import copyfile, copytree
+
+from rules_python.python.runfiles import runfiles
 
+from buf_utils import pull_buf_deps
 from detector import BufWrapper
+from tools.base.utils import cd_and_return
+from tools.run_command import run_command
 
 
 class BreakingChangeDetectorTests(object):
-    detector_type = None
 
     def run_detector_test(self, testname, is_breaking, expects_changes, additional_args=None):
         """Runs a test case for an arbitrary breaking change detector type"""
-        tests_path = Path(
-            Path(__file__).absolute().parent.parent, "testdata",
-            "api_proto_breaking_change_detector", "breaking" if is_breaking else "allowed")
-
-        current = Path(tests_path, f"{testname}_current")
-        changed = Path(tests_path, f"{testname}_next")
-
-        detector_obj = self.detector_type(current, changed, additional_args)
-        detector_obj.run_detector()
-
-        breaking_response = detector_obj.is_breaking()
-        self.assertEqual(breaking_response, is_breaking)
-
-        lock_file_changed_response = detector_obj.lock_file_changed()
-        self.assertEqual(lock_file_changed_response, expects_changes)
+        pass
 
 
 class TestBreakingChanges(BreakingChangeDetectorTests):
@@ -93,7 +85,78 @@ def test_remove_and_reserve_field(self):
 
 
 class BufTests(TestAllowedChanges, TestBreakingChanges, unittest.TestCase):
-    detector_type = BufWrapper
+    _buf_path = runfiles.Create().Rlocation("com_github_bufbuild_buf/bin/buf")
+
+    @classmethod
+    def _run_command_print_error(cls, cmd):
+        code, out, err = run_command(cmd)
+        out, err = '\n'.join(out), '\n'.join(err)
+        if code != 0:
+            raise Exception(
+                f"Error running command {cmd}\nExit code: {code} | stdout: {out} | stderr: {err}")
+
+    @classmethod
+    def setUpClass(cls):
+        try:
+            # make temp dir
+            # buf requires protobuf files to be in a subdirectory of the directory containing the yaml file
+            cls._temp_dir = tempfile.TemporaryDirectory(dir=Path.cwd())
+            cls._config_file_loc = Path(cls._temp_dir.name, "buf.yaml")
+
+            # copy in test data
+            testdata_path = Path(
+                Path.cwd(), "tools", "testdata", "api_proto_breaking_change_detector")
+            copytree(testdata_path, cls._temp_dir.name, dirs_exist_ok=True)
+
+            # copy in buf config
+            bazel_buf_config_loc = Path.cwd().joinpath(
+                "external", "envoy_api_canonical", "buf.yaml")
+            copyfile(bazel_buf_config_loc, cls._config_file_loc)
+
+            # pull buf dependencies and initialize git repo with test data files
+            with cd_and_return(cls._temp_dir.name):
+                pull_buf_deps(
+                    cls._buf_path, cls._temp_dir.name, config_file_loc=cls._config_file_loc)
+                cls._run_command_print_error('git init')
+                cls._run_command_print_error('git add .')
+                cls._run_command_print_error("git config user.name 'Bazel Test'")
+                cls._run_command_print_error("git config user.email '<>'")
+                cls._run_command_print_error('git commit -m "Initial commit"')
+        except:
+            cls.tearDownClass()
+            raise
+
+    @classmethod
+    def tearDownClass(cls):
+        cls._temp_dir.cleanup()
+
+    def tearDown(self):
+        # undo changes to proto file that were applied in test
+        with cd_and_return(self._temp_dir.name):
+            self._run_command_print_error('git reset --hard')
+
+    def run_detector_test(self, testname, is_breaking, expects_changes, additional_args=None):
+        """Runs a test case for an arbitrary breaking change detector type"""
+        tests_path = Path(self._temp_dir.name, "breaking" if is_breaking else "allowed")
+
+        target = Path(tests_path, f"{testname}.proto")
+        changed = Path(tests_path, f"{testname}_changed")
+
+        # make changes to proto file
+        copyfile(changed, target)
+
+        # buf breaking
+        detector_obj = BufWrapper(
+            self._temp_dir.name,
+            git_ref="HEAD",
+            git_path=Path(self._temp_dir.name, ".git"),
+            additional_args=additional_args,
+            buf_path=self._buf_path,
+            config_file_loc=self._config_file_loc)
+        detector_obj.run_detector()
+
+        breaking_response = detector_obj.is_breaking()
+        self.assertEqual(breaking_response, is_breaking)
 
     @unittest.skip("PGV field support not yet added to buf")
     def test_change_pgv_field(self):
diff --git a/tools/base/utils.py b/tools/base/utils.py
index cd7526b16271..ca92cdc4e78b 100644
--- a/tools/base/utils.py
+++ b/tools/base/utils.py
@@ -9,7 +9,8 @@
 import tempfile
 from configparser import ConfigParser
 from contextlib import ExitStack, contextmanager, redirect_stderr, redirect_stdout
-from typing import Callable, Iterator, List, Optional, Union
+from pathlib import Path
+from typing import Callable, ContextManager, Iterator, List, Optional, Union
 
 import yaml
 
@@ -128,3 +129,14 @@ def to_yaml(data: Union[dict, list, str, int], path: Union[pathlib.Path, str]) -
     path = pathlib.Path(path)
     path.write_text(yaml.dump(data))
     return path
+
+
+@contextmanager
+def cd_and_return(path: Union[pathlib.Path, str]) -> ContextManager[None]:
+    """Changes working directory to given path and returns to previous working directory on exit"""
+    prev_cwd = Path.cwd()
+    try:
+        os.chdir(path)
+        yield
+    finally:
+        os.chdir(prev_cwd)
diff --git a/tools/testdata/api_proto_breaking_change_detector/BUILD b/tools/testdata/api_proto_breaking_change_detector/BUILD
index 5fb56cefbd2b..0a9739fd8fb2 100644
--- a/tools/testdata/api_proto_breaking_change_detector/BUILD
+++ b/tools/testdata/api_proto_breaking_change_detector/BUILD
@@ -3,38 +3,36 @@ licenses(["notice"])  # Apache 2
 filegroup(
     name = "proto_breaking_change_detector_testdata",
     srcs = [
-        "allowed/test_add_comment_current",
-        "allowed/test_add_comment_next",
-        "allowed/test_add_enum_value_current",
-        "allowed/test_add_enum_value_next",
-        "allowed/test_add_field_current",
-        "allowed/test_add_field_next",
-        "allowed/test_add_option_current",
-        "allowed/test_add_option_next",
-        "allowed/test_force_breaking_change_current",
-        "allowed/test_force_breaking_change_next",
-        "allowed/test_remove_and_reserve_field_current",
-        "allowed/test_remove_and_reserve_field_next",
-        "breaking/test_change_field_from_oneof_current",
-        "breaking/test_change_field_from_oneof_next",
-        "breaking/test_change_field_id_current",
-        "breaking/test_change_field_id_next",
-        "breaking/test_change_field_name_current",
-        "breaking/test_change_field_name_next",
-        "breaking/test_change_field_plurality_current",
-        "breaking/test_change_field_plurality_next",
-        "breaking/test_change_field_to_oneof_current",
-        "breaking/test_change_field_to_oneof_next",
-        "breaking/test_change_field_type_current",
-        "breaking/test_change_field_type_next",
-        "breaking/test_change_package_name_current",
-        "breaking/test_change_package_name_next",
-        "breaking/test_change_pgv_field_current",
-        "breaking/test_change_pgv_field_next",
-        "breaking/test_change_pgv_message_current",
-        "breaking/test_change_pgv_message_next",
-        "breaking/test_change_pgv_oneof_current",
-        "breaking/test_change_pgv_oneof_next",
+        "allowed/test_add_comment.proto",
+        "allowed/test_add_comment_changed",
+        "allowed/test_add_enum_value.proto",
+        "allowed/test_add_enum_value_changed",
+        "allowed/test_add_field.proto",
+        "allowed/test_add_field_changed",
+        "allowed/test_add_option.proto",
+        "allowed/test_add_option_changed",
+        "allowed/test_remove_and_reserve_field.proto",
+        "allowed/test_remove_and_reserve_field_changed",
+        "breaking/test_change_field_from_oneof.proto",
+        "breaking/test_change_field_from_oneof_changed",
+        "breaking/test_change_field_id.proto",
+        "breaking/test_change_field_id_changed",
+        "breaking/test_change_field_name.proto",
+        "breaking/test_change_field_name_changed",
+        "breaking/test_change_field_plurality.proto",
+        "breaking/test_change_field_plurality_changed",
+        "breaking/test_change_field_to_oneof.proto",
+        "breaking/test_change_field_to_oneof_changed",
+        "breaking/test_change_field_type.proto",
+        "breaking/test_change_field_type_changed",
+        "breaking/test_change_package_name.proto",
+        "breaking/test_change_package_name_changed",
+        "breaking/test_change_pgv_field.proto",
+        "breaking/test_change_pgv_field_changed",
+        "breaking/test_change_pgv_message.proto",
+        "breaking/test_change_pgv_message_changed",
+        "breaking/test_change_pgv_oneof.proto",
+        "breaking/test_change_pgv_oneof_changed",
     ],
     visibility = ["//visibility:public"],
 )
diff --git a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_comment_current b/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_comment.proto
similarity index 72%
rename from tools/testdata/api_proto_breaking_change_detector/allowed/test_add_comment_current
rename to tools/testdata/api_proto_breaking_change_detector/allowed/test_add_comment.proto
index ff7a78b1fc43..b381c393588e 100644
--- a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_comment_current
+++ b/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_comment.proto
@@ -1,9 +1,9 @@
 syntax = "proto3";
-package test.protos.breaking;
+package test.protos.allowed;
 
 option java_package = "io.envoyproxy.envoy.protolock";
 option java_outer_classname = "EnvoyProtolock";
 option java_multiple_files = true;
 
-message CommonExtensionConfig {
+message AddCommentMessage {
 }
diff --git a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_option_next b/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_comment_changed
similarity index 77%
rename from tools/testdata/api_proto_breaking_change_detector/allowed/test_add_option_next
rename to tools/testdata/api_proto_breaking_change_detector/allowed/test_add_comment_changed
index 8bd44e75c89b..48b6a550c817 100644
--- a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_option_next
+++ b/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_comment_changed
@@ -1,10 +1,10 @@
 syntax = "proto3";
-package test.protos.breaking;
+package test.protos.allowed;
 
 option java_package = "io.envoyproxy.envoy.protolock";
 option java_outer_classname = "EnvoyProtolock";
 option java_multiple_files = true;
 
 // Common configuration for all tap extensions.
-message CommonExtensionConfig {
+message AddCommentMessage {
 }
diff --git a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_enum_value_current b/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_enum_value.proto
similarity index 89%
rename from tools/testdata/api_proto_breaking_change_detector/allowed/test_add_enum_value_current
rename to tools/testdata/api_proto_breaking_change_detector/allowed/test_add_enum_value.proto
index 0663f21f38ac..56cadb1af24f 100644
--- a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_enum_value_current
+++ b/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_enum_value.proto
@@ -1,5 +1,5 @@
 syntax = "proto3";
-package test.protos.breaking;
+package test.protos.allowed;
 
 message SearchRequest {
   string query = 1;
diff --git a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_enum_value_next b/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_enum_value_changed
similarity index 90%
rename from tools/testdata/api_proto_breaking_change_detector/allowed/test_add_enum_value_next
rename to tools/testdata/api_proto_breaking_change_detector/allowed/test_add_enum_value_changed
index 290aea11693c..da3446d09fa0 100644
--- a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_enum_value_next
+++ b/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_enum_value_changed
@@ -1,5 +1,5 @@
 syntax = "proto3";
-package test.protos.breaking;
+package test.protos.allowed;
 
 message SearchRequest {
   string query = 1;
diff --git a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_field.proto b/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_field.proto
new file mode 100644
index 000000000000..c16ab3037c87
--- /dev/null
+++ b/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_field.proto
@@ -0,0 +1,6 @@
+syntax = "proto3";
+package test.protos.allowed;
+
+message AddFieldMessage {
+  string three = 3;
+}
diff --git a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_field_next b/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_field_changed
similarity index 53%
rename from tools/testdata/api_proto_breaking_change_detector/allowed/test_add_field_next
rename to tools/testdata/api_proto_breaking_change_detector/allowed/test_add_field_changed
index b17fe188e3fe..49e8d2816997 100644
--- a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_field_next
+++ b/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_field_changed
@@ -1,7 +1,7 @@
 syntax = "proto3";
-package test.protos.breaking;
+package test.protos.allowed;
 
-message SampleMessage {
+message AddFieldMessage {
     string three = 3;
     float four = 4;
 }
diff --git a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_option_current b/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_option.proto
similarity index 73%
rename from tools/testdata/api_proto_breaking_change_detector/allowed/test_add_option_current
rename to tools/testdata/api_proto_breaking_change_detector/allowed/test_add_option.proto
index f6f3f59b856d..498895fbbb8b 100644
--- a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_option_current
+++ b/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_option.proto
@@ -1,9 +1,9 @@
 syntax = "proto3";
-package test.protos.breaking;
+package test.protos.allowed;
 
 option java_package = "io.envoyproxy.envoy.protolock";
 option java_outer_classname = "EnvoyProtolock";
 
 // Common configuration for all tap extensions.
-message CommonExtensionConfig {
+message AddOptionMessage {
 }
diff --git a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_comment_next b/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_option_changed
similarity index 77%
rename from tools/testdata/api_proto_breaking_change_detector/allowed/test_add_comment_next
rename to tools/testdata/api_proto_breaking_change_detector/allowed/test_add_option_changed
index 8bd44e75c89b..1aca28ad4bed 100644
--- a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_comment_next
+++ b/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_option_changed
@@ -1,10 +1,10 @@
 syntax = "proto3";
-package test.protos.breaking;
+package test.protos.allowed;
 
 option java_package = "io.envoyproxy.envoy.protolock";
 option java_outer_classname = "EnvoyProtolock";
 option java_multiple_files = true;
 
 // Common configuration for all tap extensions.
-message CommonExtensionConfig {
+message AddOptionMessage {
 }
diff --git a/tools/testdata/api_proto_breaking_change_detector/allowed/test_force_breaking_change_current b/tools/testdata/api_proto_breaking_change_detector/allowed/test_force_breaking_change_current
deleted file mode 100644
index 4a38563f01d9..000000000000
--- a/tools/testdata/api_proto_breaking_change_detector/allowed/test_force_breaking_change_current
+++ /dev/null
@@ -1,6 +0,0 @@
-syntax = "proto3";
-package test.protos.breaking;
-
-message SampleMessage {
-    string three = 3;
-}
diff --git a/tools/testdata/api_proto_breaking_change_detector/allowed/test_force_breaking_change_next b/tools/testdata/api_proto_breaking_change_detector/allowed/test_force_breaking_change_next
deleted file mode 100644
index 2059fdb4f514..000000000000
--- a/tools/testdata/api_proto_breaking_change_detector/allowed/test_force_breaking_change_next
+++ /dev/null
@@ -1,6 +0,0 @@
-syntax = "proto3";
-package test.protos.breaking;
-
-message SampleMessage {
-    float three = 3;
-}
diff --git a/tools/testdata/api_proto_breaking_change_detector/allowed/test_remove_and_reserve_field.proto b/tools/testdata/api_proto_breaking_change_detector/allowed/test_remove_and_reserve_field.proto
new file mode 100644
index 000000000000..22b7ce3a7b08
--- /dev/null
+++ b/tools/testdata/api_proto_breaking_change_detector/allowed/test_remove_and_reserve_field.proto
@@ -0,0 +1,7 @@
+syntax = "proto3";
+package test.protos.allowed;
+
+message RemoveReserveFieldMessage {
+  string three = 3;
+  float four = 4;
+}
diff --git a/tools/testdata/api_proto_breaking_change_detector/allowed/test_remove_and_reserve_field_next b/tools/testdata/api_proto_breaking_change_detector/allowed/test_remove_and_reserve_field_changed
similarity index 55%
rename from tools/testdata/api_proto_breaking_change_detector/allowed/test_remove_and_reserve_field_next
rename to tools/testdata/api_proto_breaking_change_detector/allowed/test_remove_and_reserve_field_changed
index f2ffa0510ad3..e226ff0130f7 100644
--- a/tools/testdata/api_proto_breaking_change_detector/allowed/test_remove_and_reserve_field_next
+++ b/tools/testdata/api_proto_breaking_change_detector/allowed/test_remove_and_reserve_field_changed
@@ -1,7 +1,7 @@
 syntax = "proto3";
-package test.protos.breaking;
+package test.protos.allowed;
 
-message SampleMessage {
+message RemoveReserveFieldMessage {
     reserved 4;
     reserved "four";
 
diff --git a/tools/testdata/api_proto_breaking_change_detector/allowed/test_remove_and_reserve_field_current b/tools/testdata/api_proto_breaking_change_detector/allowed/test_remove_and_reserve_field_current
deleted file mode 100644
index b17fe188e3fe..000000000000
--- a/tools/testdata/api_proto_breaking_change_detector/allowed/test_remove_and_reserve_field_current
+++ /dev/null
@@ -1,7 +0,0 @@
-syntax = "proto3";
-package test.protos.breaking;
-
-message SampleMessage {
-    string three = 3;
-    float four = 4;
-}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_from_oneof.proto b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_from_oneof.proto
new file mode 100644
index 000000000000..945e6ab9c8c5
--- /dev/null
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_from_oneof.proto
@@ -0,0 +1,10 @@
+syntax = "proto3";
+package test.protos.breaking;
+
+message FromOneofMessage {
+  oneof test_oneof {
+    string name = 4;
+    string sub_message = 9;
+    float special = 10;
+  }
+}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_from_oneof_next b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_from_oneof_changed
similarity index 85%
rename from tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_from_oneof_next
rename to tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_from_oneof_changed
index b4965f64fd7a..2aa8f4e02a0e 100644
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_from_oneof_next
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_from_oneof_changed
@@ -1,7 +1,7 @@
 syntax = "proto3";
 package test.protos.breaking;
 
-message SampleMessage {
+message FromOneofMessage {
     oneof test_oneof {
       string name = 4;
       string sub_message = 9;
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_from_oneof_current b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_from_oneof_current
deleted file mode 100644
index 564601045ee9..000000000000
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_from_oneof_current
+++ /dev/null
@@ -1,10 +0,0 @@
-syntax = "proto3";
-package test.protos.breaking;
-
-message SampleMessage {
-    oneof test_oneof {
-      string name = 4;
-      string sub_message = 9;
-      float special = 10;
-    }
-}
diff --git a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_field_current b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_id.proto
similarity index 50%
rename from tools/testdata/api_proto_breaking_change_detector/allowed/test_add_field_current
rename to tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_id.proto
index 4a38563f01d9..15c0521a89e4 100644
--- a/tools/testdata/api_proto_breaking_change_detector/allowed/test_add_field_current
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_id.proto
@@ -1,6 +1,6 @@
 syntax = "proto3";
 package test.protos.breaking;
 
-message SampleMessage {
-    string three = 3;
+message ChangeFieldIdMessage {
+  string three = 3;
 }
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_id_next b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_id_changed
similarity index 70%
rename from tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_id_next
rename to tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_id_changed
index 35984ed9637b..9c31f1709402 100644
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_id_next
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_id_changed
@@ -1,6 +1,6 @@
 syntax = "proto3";
 package test.protos.breaking;
 
-message SampleMessage {
+message ChangeFieldIdMessage {
     string three = 42;
 }
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_name.proto b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_name.proto
new file mode 100644
index 000000000000..ed0e9b1af7f6
--- /dev/null
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_name.proto
@@ -0,0 +1,6 @@
+syntax = "proto3";
+package test.protos.breaking;
+
+message ChangeFieldNameMessage {
+  string seventeen = 17;
+}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_name_next b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_name_changed
similarity index 69%
rename from tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_name_next
rename to tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_name_changed
index c6003d138489..7a6e4b181969 100644
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_name_next
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_name_changed
@@ -1,6 +1,6 @@
 syntax = "proto3";
 package test.protos.breaking;
 
-message SampleMessage {
+message ChangeFieldNameMessage {
     string twenty = 17;
 }
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_name_current b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_name_current
deleted file mode 100644
index 4471dbbb1a20..000000000000
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_name_current
+++ /dev/null
@@ -1,6 +0,0 @@
-syntax = "proto3";
-package test.protos.breaking;
-
-message SampleMessage {
-    string seventeen = 17;
-}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_plurality.proto b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_plurality.proto
new file mode 100644
index 000000000000..7e15732e1952
--- /dev/null
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_plurality.proto
@@ -0,0 +1,6 @@
+syntax = "proto3";
+package test.protos.breaking;
+
+message ChangeFieldPluralityMessage {
+  string from = 1;
+}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_plurality_next b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_plurality_changed
similarity index 68%
rename from tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_plurality_next
rename to tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_plurality_changed
index 63a5af85d0b2..5c11b9375ba4 100644
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_plurality_next
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_plurality_changed
@@ -1,6 +1,6 @@
 syntax = "proto3";
 package test.protos.breaking;
 
-message SampleMessage {
+message ChangeFieldPluralityMessage {
     repeated string from = 1;
 }
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_plurality_current b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_plurality_current
deleted file mode 100644
index 09e5e4374eef..000000000000
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_plurality_current
+++ /dev/null
@@ -1,6 +0,0 @@
-syntax = "proto3";
-package test.protos.breaking;
-
-message SampleMessage {
-    string from = 1;
-}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_to_oneof.proto b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_to_oneof.proto
new file mode 100644
index 000000000000..008ac77757c7
--- /dev/null
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_to_oneof.proto
@@ -0,0 +1,10 @@
+syntax = "proto3";
+package test.protos.breaking;
+
+message ToOneofMessage {
+  oneof test_oneof {
+    string name = 4;
+    string sub_message = 9;
+  }
+  float loner = 10;
+}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_to_oneof_next b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_to_oneof_changed
similarity index 86%
rename from tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_to_oneof_next
rename to tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_to_oneof_changed
index 3336f4e384e9..564d9dd19660 100644
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_to_oneof_next
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_to_oneof_changed
@@ -1,7 +1,7 @@
 syntax = "proto3";
 package test.protos.breaking;
 
-message SampleMessage {
+message ToOneofMessage {
     oneof test_oneof {
       string name = 4;
       string sub_message = 9;
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_to_oneof_current b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_to_oneof_current
deleted file mode 100644
index 1bb452fdb941..000000000000
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_to_oneof_current
+++ /dev/null
@@ -1,10 +0,0 @@
-syntax = "proto3";
-package test.protos.breaking;
-
-message SampleMessage {
-    oneof test_oneof {
-      string name = 4;
-      string sub_message = 9;
-    }
-    float loner = 10;
-}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_id_current b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_type.proto
similarity index 50%
rename from tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_id_current
rename to tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_type.proto
index 4a38563f01d9..3762ae0600e7 100644
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_id_current
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_type.proto
@@ -1,6 +1,6 @@
 syntax = "proto3";
 package test.protos.breaking;
 
-message SampleMessage {
-    string three = 3;
+message ChangeFieldTypeMessage {
+  float pi = 314;
 }
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_type_next b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_type_changed
similarity index 68%
rename from tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_type_next
rename to tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_type_changed
index b235c8e224d0..7ce276c75fe6 100644
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_type_next
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_type_changed
@@ -1,6 +1,6 @@
 syntax = "proto3";
 package test.protos.breaking;
 
-message SampleMessage {
+message ChangeFieldTypeMessage {
     string pi = 314;
 }
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_type_current b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_type_current
deleted file mode 100644
index 5cae750860e1..000000000000
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_field_type_current
+++ /dev/null
@@ -1,6 +0,0 @@
-syntax = "proto3";
-package test.protos.breaking;
-
-message SampleMessage {
-    float pi = 314;
-}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_package_name.proto b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_package_name.proto
new file mode 100644
index 000000000000..512e1c14d1b6
--- /dev/null
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_package_name.proto
@@ -0,0 +1,6 @@
+syntax = "proto3";
+package test.protos.breaking;
+
+message ChangePackageNameMessage {
+  string passcode = 69;
+}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_package_name_next b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_package_name_changed
similarity index 66%
rename from tools/testdata/api_proto_breaking_change_detector/breaking/test_change_package_name_next
rename to tools/testdata/api_proto_breaking_change_detector/breaking/test_change_package_name_changed
index 867e36699374..a8d583e6d117 100644
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_package_name_next
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_package_name_changed
@@ -1,6 +1,6 @@
 syntax = "proto3";
 package wrong.package;
 
-message SampleMessage {
+message ChangePackageNameMessage {
     string passcode = 69;
 }
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_package_name_current b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_package_name_current
deleted file mode 100644
index f48663822058..000000000000
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_package_name_current
+++ /dev/null
@@ -1,6 +0,0 @@
-syntax = "proto3";
-package test.protos.breaking;
-
-message SampleMessage {
-    string passcode = 69;
-}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_field.proto b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_field.proto
new file mode 100644
index 000000000000..14d1349b5e45
--- /dev/null
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_field.proto
@@ -0,0 +1,8 @@
+syntax = "proto3";
+package test.protos.breaking;
+
+import "validate/validate.proto";
+
+message ChangePGVFieldMessage {
+  string useremail = 1 [(validate.rules).string.email = true];
+}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_field_next b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_field_changed
similarity index 63%
rename from tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_field_next
rename to tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_field_changed
index 2715676735f3..7c673f49cd63 100644
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_field_next
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_field_changed
@@ -1,6 +1,8 @@
 syntax = "proto3";
 package test.protos.breaking;
 
-message SampleMessage {
+import "validate/validate.proto";
+
+message ChangePGVFieldMessage {
     string useremail = 1 [(validate.rules).string.email = false];
 }
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_field_current b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_field_current
deleted file mode 100644
index 72b792e819e5..000000000000
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_field_current
+++ /dev/null
@@ -1,6 +0,0 @@
-syntax = "proto3";
-package test.protos.breaking;
-
-message SampleMessage {
-    string useremail = 1 [(validate.rules).string.email = true];
-}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_message.proto b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_message.proto
new file mode 100644
index 000000000000..107189d5aec1
--- /dev/null
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_message.proto
@@ -0,0 +1,10 @@
+syntax = "proto3";
+package test.protos.breaking;
+
+import "validate/validate.proto";
+
+message ChangePGVMessageMessage {
+  option (validate.disabled) = true;
+
+  ChangePGVMessageMessage q = 543;
+}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_message_changed b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_message_changed
new file mode 100644
index 000000000000..6732ead334d6
--- /dev/null
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_message_changed
@@ -0,0 +1,10 @@
+syntax = "proto3";
+package test.protos.breaking;
+
+import "validate/validate.proto";
+
+message ChangePGVMessageMessage {
+    option (validate.disabled) = false;
+
+    ChangePGVMessageMessage q = 543;
+}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_message_current b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_message_current
deleted file mode 100644
index 1df9b09c14b2..000000000000
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_message_current
+++ /dev/null
@@ -1,8 +0,0 @@
-syntax = "proto3";
-package test.protos.breaking;
-
-message SampleMessage {
-    option (validate.disabled) = true;
-
-    SampleMessage q = 543;
-}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_message_next b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_message_next
deleted file mode 100644
index 62fd2266f00f..000000000000
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_message_next
+++ /dev/null
@@ -1,8 +0,0 @@
-syntax = "proto3";
-package test.protos.breaking;
-
-message SampleMessage {
-    option (validate.disabled) = false;
-
-    SampleMessage q = 543;
-}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_oneof.proto b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_oneof.proto
new file mode 100644
index 000000000000..b93b51a98110
--- /dev/null
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_oneof.proto
@@ -0,0 +1,12 @@
+syntax = "proto3";
+package test.protos.breaking;
+
+import "validate/validate.proto";
+
+message ChangePGVOneofMessage {
+  oneof test_oneof {
+    option (validate.required) = true;
+    string name = 4;
+    string sub_message = 9;
+  }
+}
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_oneof_next b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_oneof_changed
similarity index 60%
rename from tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_oneof_next
rename to tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_oneof_changed
index 989642b4aca8..f376cd74caac 100644
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_oneof_next
+++ b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_oneof_changed
@@ -1,10 +1,12 @@
 syntax = "proto3";
 package test.protos.breaking;
 
-message SampleMessage {
+import "validate/validate.proto";
+
+message ChangePGVOneofMessage {
     oneof test_oneof {
       option (validate.required) = false;
       string name = 4;
-      string sub_message = 9;;
+      string sub_message = 9;
     }
 }
diff --git a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_oneof_current b/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_oneof_current
deleted file mode 100644
index 266d6fee1cfd..000000000000
--- a/tools/testdata/api_proto_breaking_change_detector/breaking/test_change_pgv_oneof_current
+++ /dev/null
@@ -1,10 +0,0 @@
-syntax = "proto3";
-package test.protos.breaking;
-
-message SampleMessage {
-    oneof test_oneof {
-      option (validate.required) = true;
-      string name = 4;
-      string sub_message = 9;;
-    }
-}
diff --git a/tools/type_whisperer/proto_build_targets_gen.py b/tools/type_whisperer/proto_build_targets_gen.py
index 2fd33ac0361c..2da22439946f 100644
--- a/tools/type_whisperer/proto_build_targets_gen.py
+++ b/tools/type_whisperer/proto_build_targets_gen.py
@@ -66,6 +66,14 @@
         ":v3_protos",
     ],
 )
+
+filegroup(
+    name = "proto_breaking_change_detector_buf_config",
+    srcs = [
+        "buf.yaml",
+    ],
+    visibility = ["//visibility:public"],
+)
 """)