diff --git a/Makefile b/Makefile
index 3edf484c..2b08c06b 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-.PHONY: build cover test test-integration test-integration-tgb test-integration-gob bench lint proto gazelle clean clean-proto run-server run-client-get-graph run-client-changed-targets version help
+.PHONY: build cover test test-integration test-integration-tgb test-integration-gob test-integration-atf bench lint proto gazelle clean clean-proto run-server run-client-get-graph run-client-changed-targets version help
 
 # Bazel wrapper
 BAZEL = ./tools/bazel
@@ -20,15 +20,28 @@ FIXTURE_BASE_SHA ?= 0d79296cfd507440f536ea01e626b294d74d19a8
 FIXTURE_HEAD_SHA ?= b5f81eb872dfcbe4c13131a73367122eb2d92065
 FIXTURE_PR_URL  ?= github://github.com/xytan0056/bazel-fixture/pull/2/$(FIXTURE_HEAD_SHA)
 
-INTEGRATION_ENV = \
+ATF_BASE_SHA    ?= 0d79296cfd507440f536ea01e626b294d74d19a8
+ATF_HEAD_SHA    ?= fd703ed51746d989e3b793876e5610bcf0d68c7a
+ATF_PR_URL      ?= github://github.com/xytan0056/bazel-fixture/pull/3/$(ATF_HEAD_SHA)
+
+COMMON_ENV = \
 	--test_env=HOME=$$HOME \
-	--test_env=TANGO_REPO_REMOTE=$(FIXTURE_REMOTE) \
+	--test_env=TANGO_REPO_REMOTE=$(FIXTURE_REMOTE)
+
+INTEGRATION_ENV = \
+	$(COMMON_ENV) \
 	--test_env=TANGO_BASE_SHA=$(FIXTURE_BASE_SHA) \
 	--test_env=TANGO_HEAD_SHA=$(FIXTURE_HEAD_SHA) \
 	--test_env=TANGO_PR_URL=$(FIXTURE_PR_URL)
 
-# Run integration tests with both graph formats
-test-integration: test-integration-tgb test-integration-gob
+ATF_ENV = \
+	$(COMMON_ENV) \
+	--test_env=TANGO_ATF_BASE_SHA=$(ATF_BASE_SHA) \
+	--test_env=TANGO_ATF_HEAD_SHA=$(ATF_HEAD_SHA) \
+	--test_env=TANGO_ATF_PR_URL=$(ATF_PR_URL)
+
+# Run all integration test suites
+test-integration: test-integration-tgb test-integration-gob test-integration-atf
 
 test-integration-tgb:
 	@echo "Running integration tests (tgb)..."
@@ -42,6 +55,13 @@ test-integration-gob:
 		$(INTEGRATION_ENV) --test_env=TANGO_GRAPH_FORMAT=gob
 	@echo "Integration tests (gob) passed!"
 
+test-integration-atf:
+	@echo "Running AllTargetsFiles integration tests (tgb)..."
+	@$(BAZEL) test //integration:integration_test --test_output=errors \
+		--test_filter=AllTargetsFiles \
+		$(ATF_ENV) --test_env=TANGO_GRAPH_FORMAT=tgb
+	@echo "AllTargetsFiles integration tests passed!"
+
 # Run GetChangedTargets benchmarks against fixed, checked-in commit pairs.
 # Measurement only: not part of `make test` / `make test-integration` and not
 # run in CI, so a slow benchmark never fails the build.
@@ -137,9 +157,10 @@ help:
 	@echo "Build & Test:"
 	@echo "  make build            - Build all targets"
 	@echo "  make test             - Run all tests"
-	@echo "  make test-integration     - Run integration tests with both formats (needs network, slow)"
+	@echo "  make test-integration     - Run all integration test suites (needs network, slow)"
 	@echo "  make test-integration-tgb - Run integration tests with TGB format"
 	@echo "  make test-integration-gob - Run integration tests with gob format"
+	@echo "  make test-integration-atf - Run AllTargetsFiles integration tests (TGB only)"
 	@echo "  make bench            - Run GetChangedTargets benchs (measurement only, not in CI)"
 	@echo "  make lint             - Run golangci-lint"
 	@echo "  make gazelle          - Update BUILD.bazel files"
diff --git a/integration/BUILD.bazel b/integration/BUILD.bazel
index c71ce849..56aab381 100644
--- a/integration/BUILD.bazel
+++ b/integration/BUILD.bazel
@@ -5,6 +5,7 @@ go_test(
     size = "large",
     timeout = "long",
     srcs = [
+        "atf_test.go",
         "benchmark_test.go",
         "integration_test.go",
     ],
diff --git a/integration/atf_test.go b/integration/atf_test.go
new file mode 100644
index 00000000..ee2add3f
--- /dev/null
+++ b/integration/atf_test.go
@@ -0,0 +1,108 @@
+// Copyright (c) 2026 Uber Technologies, Inc.
+//
+// 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.
+
+package integration_test
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	pb "github.com/uber/tango/tangopb"
+)
+
+func skipUnlessATF(t testing.TB) {
+	t.Helper()
+	if os.Getenv("TANGO_ATF_BASE_SHA") == "" {
+		t.Skip("TANGO_ATF_* env vars not set, skipping AllTargetsFiles tests")
+	}
+}
+
+func atfBaseSHA(t testing.TB) string {
+	t.Helper()
+	return requiredEnv(t, "TANGO_ATF_BASE_SHA")
+}
+
+func atfHeadSHA(t testing.TB) string {
+	t.Helper()
+	return requiredEnv(t, "TANGO_ATF_HEAD_SHA")
+}
+
+func atfPRURL(t testing.TB) string {
+	t.Helper()
+	return requiredEnv(t, "TANGO_ATF_PR_URL")
+}
+
+// TestIntegration_AllTargetsFiles verifies BUG-015: when an all_targets_files
+// trigger fires (.bazelrc changes), NEW and DELETED change types are preserved
+// while targets present in both revisions are promoted to CHANGED at distance 0.
+func TestIntegration_AllTargetsFiles(t *testing.T) {
+	skipUnlessATF(t)
+	remote := repoRemote(t)
+	addr := startServer(t, remote)
+	client := newClient(t, addr)
+
+	t.Run("sha_comparison", func(t *testing.T) {
+		ct := getChangedTargets(t, client,
+			buildDesc(remote, atfBaseSHA(t)),
+			buildDesc(remote, atfHeadSHA(t)),
+		)
+
+		t.Logf("NEW: %v", ct.ByType[pb.CHANGE_TYPE_NEW])
+		t.Logf("DELETED: %v", ct.ByType[pb.CHANGE_TYPE_DELETED])
+		t.Logf("CHANGED: %v", ct.ByType[pb.CHANGE_TYPE_CHANGED])
+		t.Logf("Distances: %v", ct.Distances)
+
+		assert.NotEmpty(t, ct.ByType[pb.CHANGE_TYPE_NEW], "expected NEW targets")
+		assert.NotEmpty(t, ct.ByType[pb.CHANGE_TYPE_DELETED], "expected DELETED targets")
+		assert.NotEmpty(t, ct.ByType[pb.CHANGE_TYPE_CHANGED], "expected CHANGED targets")
+
+		assertContainsTarget(t, ct.ByType[pb.CHANGE_TYPE_NEW], "//pkg/printer:printer", "NEW")
+		assertContainsTarget(t, ct.ByType[pb.CHANGE_TYPE_DELETED], "//pkg/version:version", "DELETED")
+
+		for _, name := range ct.ByType[pb.CHANGE_TYPE_CHANGED] {
+			assert.Equal(t, int32(0), ct.Distances[name],
+				"all CHANGED targets must be distance 0 under AllTargetsFiles trigger, but %q has distance %d", name, ct.Distances[name])
+		}
+	})
+
+	t.Run("pr_change_request", func(t *testing.T) {
+		ct := getChangedTargets(t, client,
+			buildDesc(remote, atfBaseSHA(t)),
+			&pb.BuildDescription{
+				Strategy: pb.COMPUTATION_STRATEGY_UNSET,
+				Remote:   remote,
+				BaseSha:  atfBaseSHA(t),
+				Requests: []*pb.Request{{Url: atfPRURL(t)}},
+			},
+		)
+
+		t.Logf("NEW: %v", ct.ByType[pb.CHANGE_TYPE_NEW])
+		t.Logf("DELETED: %v", ct.ByType[pb.CHANGE_TYPE_DELETED])
+		t.Logf("CHANGED: %v", ct.ByType[pb.CHANGE_TYPE_CHANGED])
+		t.Logf("Distances: %v", ct.Distances)
+
+		assert.NotEmpty(t, ct.ByType[pb.CHANGE_TYPE_NEW], "expected NEW targets")
+		assert.NotEmpty(t, ct.ByType[pb.CHANGE_TYPE_DELETED], "expected DELETED targets")
+		assert.NotEmpty(t, ct.ByType[pb.CHANGE_TYPE_CHANGED], "expected CHANGED targets")
+
+		assertContainsTarget(t, ct.ByType[pb.CHANGE_TYPE_NEW], "//pkg/printer:printer", "NEW")
+		assertContainsTarget(t, ct.ByType[pb.CHANGE_TYPE_DELETED], "//pkg/version:version", "DELETED")
+
+		for _, name := range ct.ByType[pb.CHANGE_TYPE_CHANGED] {
+			assert.Equal(t, int32(0), ct.Distances[name],
+				"all CHANGED targets must be distance 0 under AllTargetsFiles trigger, but %q has distance %d", name, ct.Distances[name])
+		}
+	})
+}
diff --git a/integration/testdata/tango-config.yaml.tmpl b/integration/testdata/tango-config.yaml.tmpl
index 3bcb21ec..d45a7771 100644
--- a/integration/testdata/tango-config.yaml.tmpl
+++ b/integration/testdata/tango-config.yaml.tmpl
@@ -13,6 +13,7 @@ repository:
     # Batch mode avoids a persistent Bazel server, which can wedge when a pooled worker's tree is swapped by `git checkout` between queries.
     bazel_startup_options: ["--batch"]
     query_timeout_seconds: 600
+    all_targets_files: [".bazelrc"]
 
 service:
   max_worker_pool_size: 2