diff --git a/submitqueue/extension/conflict/tango/BUILD.bazel b/submitqueue/extension/conflict/tango/BUILD.bazel
new file mode 100644
index 000000000..10f193dd1
--- /dev/null
+++ b/submitqueue/extension/conflict/tango/BUILD.bazel
@@ -0,0 +1,14 @@
+load("@rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "mock_store.go",
+        "store.go",
+        "target_label.go",
+        "target_signature.go",
+    ],
+    importpath = "github.com/uber/submitqueue/submitqueue/extension/conflict/tango",
+    visibility = ["//visibility:public"],
+    deps = ["@org_uber_go_mock//gomock:go_default_library"],
+)
diff --git a/submitqueue/extension/conflict/tango/mock_store.go b/submitqueue/extension/conflict/tango/mock_store.go
new file mode 100644
index 000000000..8293d8f0d
--- /dev/null
+++ b/submitqueue/extension/conflict/tango/mock_store.go
@@ -0,0 +1,205 @@
+// Code generated by MockGen. DO NOT EDIT.
+// Source: store.go
+//
+// Generated by this command:
+//
+//	mockgen -source=store.go -destination=mock_store.go -package=tango
+//
+
+// Package tango is a generated GoMock package.
+package tango
+
+import (
+	context "context"
+	reflect "reflect"
+
+	gomock "go.uber.org/mock/gomock"
+)
+
+// MockSignatureReader is a mock of SignatureReader interface.
+type MockSignatureReader struct {
+	ctrl     *gomock.Controller
+	recorder *MockSignatureReaderMockRecorder
+	isgomock struct{}
+}
+
+// MockSignatureReaderMockRecorder is the mock recorder for MockSignatureReader.
+type MockSignatureReaderMockRecorder struct {
+	mock *MockSignatureReader
+}
+
+// NewMockSignatureReader creates a new mock instance.
+func NewMockSignatureReader(ctrl *gomock.Controller) *MockSignatureReader {
+	mock := &MockSignatureReader{ctrl: ctrl}
+	mock.recorder = &MockSignatureReaderMockRecorder{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockSignatureReader) EXPECT() *MockSignatureReaderMockRecorder {
+	return m.recorder
+}
+
+// Get mocks base method.
+func (m *MockSignatureReader) Get(ctx context.Context, batchID string) (TargetSignature, bool, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Get", ctx, batchID)
+	ret0, _ := ret[0].(TargetSignature)
+	ret1, _ := ret[1].(bool)
+	ret2, _ := ret[2].(error)
+	return ret0, ret1, ret2
+}
+
+// Get indicates an expected call of Get.
+func (mr *MockSignatureReaderMockRecorder) Get(ctx, batchID any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Get", reflect.TypeOf((*MockSignatureReader)(nil).Get), ctx, batchID)
+}
+
+// MockSignatureStore is a mock of SignatureStore interface.
+type MockSignatureStore struct {
+	ctrl     *gomock.Controller
+	recorder *MockSignatureStoreMockRecorder
+	isgomock struct{}
+}
+
+// MockSignatureStoreMockRecorder is the mock recorder for MockSignatureStore.
+type MockSignatureStoreMockRecorder struct {
+	mock *MockSignatureStore
+}
+
+// NewMockSignatureStore creates a new mock instance.
+func NewMockSignatureStore(ctrl *gomock.Controller) *MockSignatureStore {
+	mock := &MockSignatureStore{ctrl: ctrl}
+	mock.recorder = &MockSignatureStoreMockRecorder{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockSignatureStore) EXPECT() *MockSignatureStoreMockRecorder {
+	return m.recorder
+}
+
+// Create mocks base method.
+func (m *MockSignatureStore) Create(ctx context.Context, signature TargetSignature) error {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Create", ctx, signature)
+	ret0, _ := ret[0].(error)
+	return ret0
+}
+
+// Create indicates an expected call of Create.
+func (mr *MockSignatureStoreMockRecorder) Create(ctx, signature any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Create", reflect.TypeOf((*MockSignatureStore)(nil).Create), ctx, signature)
+}
+
+// Get mocks base method.
+func (m *MockSignatureStore) Get(ctx context.Context, batchID string) (TargetSignature, bool, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Get", ctx, batchID)
+	ret0, _ := ret[0].(TargetSignature)
+	ret1, _ := ret[1].(bool)
+	ret2, _ := ret[2].(error)
+	return ret0, ret1, ret2
+}
+
+// Get indicates an expected call of Get.
+func (mr *MockSignatureStoreMockRecorder) Get(ctx, batchID any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Get", reflect.TypeOf((*MockSignatureStore)(nil).Get), ctx, batchID)
+}
+
+// MockDictionaryReader is a mock of DictionaryReader interface.
+type MockDictionaryReader struct {
+	ctrl     *gomock.Controller
+	recorder *MockDictionaryReaderMockRecorder
+	isgomock struct{}
+}
+
+// MockDictionaryReaderMockRecorder is the mock recorder for MockDictionaryReader.
+type MockDictionaryReaderMockRecorder struct {
+	mock *MockDictionaryReader
+}
+
+// NewMockDictionaryReader creates a new mock instance.
+func NewMockDictionaryReader(ctrl *gomock.Controller) *MockDictionaryReader {
+	mock := &MockDictionaryReader{ctrl: ctrl}
+	mock.recorder = &MockDictionaryReaderMockRecorder{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockDictionaryReader) EXPECT() *MockDictionaryReaderMockRecorder {
+	return m.recorder
+}
+
+// Get mocks base method.
+func (m *MockDictionaryReader) Get(ctx context.Context, id uint64) (TargetLabel, bool, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Get", ctx, id)
+	ret0, _ := ret[0].(TargetLabel)
+	ret1, _ := ret[1].(bool)
+	ret2, _ := ret[2].(error)
+	return ret0, ret1, ret2
+}
+
+// Get indicates an expected call of Get.
+func (mr *MockDictionaryReaderMockRecorder) Get(ctx, id any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Get", reflect.TypeOf((*MockDictionaryReader)(nil).Get), ctx, id)
+}
+
+// MockDictionaryStore is a mock of DictionaryStore interface.
+type MockDictionaryStore struct {
+	ctrl     *gomock.Controller
+	recorder *MockDictionaryStoreMockRecorder
+	isgomock struct{}
+}
+
+// MockDictionaryStoreMockRecorder is the mock recorder for MockDictionaryStore.
+type MockDictionaryStoreMockRecorder struct {
+	mock *MockDictionaryStore
+}
+
+// NewMockDictionaryStore creates a new mock instance.
+func NewMockDictionaryStore(ctrl *gomock.Controller) *MockDictionaryStore {
+	mock := &MockDictionaryStore{ctrl: ctrl}
+	mock.recorder = &MockDictionaryStoreMockRecorder{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockDictionaryStore) EXPECT() *MockDictionaryStoreMockRecorder {
+	return m.recorder
+}
+
+// Create mocks base method.
+func (m *MockDictionaryStore) Create(ctx context.Context, label TargetLabel) error {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Create", ctx, label)
+	ret0, _ := ret[0].(error)
+	return ret0
+}
+
+// Create indicates an expected call of Create.
+func (mr *MockDictionaryStoreMockRecorder) Create(ctx, label any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Create", reflect.TypeOf((*MockDictionaryStore)(nil).Create), ctx, label)
+}
+
+// Get mocks base method.
+func (m *MockDictionaryStore) Get(ctx context.Context, id uint64) (TargetLabel, bool, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Get", ctx, id)
+	ret0, _ := ret[0].(TargetLabel)
+	ret1, _ := ret[1].(bool)
+	ret2, _ := ret[2].(error)
+	return ret0, ret1, ret2
+}
+
+// Get indicates an expected call of Get.
+func (mr *MockDictionaryStoreMockRecorder) Get(ctx, id any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Get", reflect.TypeOf((*MockDictionaryStore)(nil).Get), ctx, id)
+}
diff --git a/submitqueue/extension/conflict/tango/store.go b/submitqueue/extension/conflict/tango/store.go
new file mode 100644
index 000000000..0061bc5d7
--- /dev/null
+++ b/submitqueue/extension/conflict/tango/store.go
@@ -0,0 +1,60 @@
+// 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 tango
+
+//go:generate mockgen -source=store.go -destination=mock_store.go -package=tango
+
+import "context"
+
+// SignatureReader reads the target signature of a batch. It is the read-only
+// view of SignatureStore for consumers that must not write.
+type SignatureReader interface {
+	// Get returns the signature of batchID in the bound queue. The bool is
+	// false when no signature has been created for the batch.
+	Get(ctx context.Context, batchID string) (TargetSignature, bool, error)
+}
+
+// SignatureStore persists target signatures. A signature is immutable: it is
+// created once under (Queue, BatchID) and never updated. Reads and writes are
+// per-batch point operations, so any backend can implement it.
+type SignatureStore interface {
+	SignatureReader
+
+	// Create persists signature in one write. Returns an already-exists error
+	// if the bound queue already holds a signature for signature.BatchID, so the
+	// first signature written stays and the caller can read it back with Get.
+	Create(ctx context.Context, signature TargetSignature) error
+}
+
+// DictionaryReader reads the label recorded for a target ID. It is the
+// read-only view of DictionaryStore.
+type DictionaryReader interface {
+	// Get returns the label recorded for id in the bound queue. The bool is
+	// false when none has been recorded.
+	Get(ctx context.Context, id uint64) (TargetLabel, bool, error)
+}
+
+// DictionaryStore persists the target dictionary: one TargetLabel for each
+// 64-bit target ID. A record is immutable: it is created once under
+// (Queue, ID) and never updated. Two labels can share an ID, so the first label
+// recorded stays and the caller can read it back with Get to detect a collision.
+type DictionaryStore interface {
+	DictionaryReader
+
+	// Create persists label in one write. Returns an already-exists error if
+	// the bound queue holds a label for label.ID, whether or not it is the same
+	// label, so repeating a write is harmless.
+	Create(ctx context.Context, label TargetLabel) error
+}
diff --git a/submitqueue/extension/conflict/tango/target_label.go b/submitqueue/extension/conflict/tango/target_label.go
new file mode 100644
index 000000000..2bfa70bd2
--- /dev/null
+++ b/submitqueue/extension/conflict/tango/target_label.go
@@ -0,0 +1,33 @@
+// 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 tango
+
+// TargetLabel is one build target label and the 64-bit ID it hashes to. The
+// whole record is immutable: (Queue, ID) is its identity and there is no update
+// path. Two labels can share an ID on a hash collision; the first one recorded
+// stays.
+type TargetLabel struct {
+	// Queue is the queue the label was seen in. Unique together with ID.
+	Queue string
+
+	// ID is the 64-bit hash of Label.
+	ID uint64
+
+	// Label is the target label exactly as the build graph reported it.
+	Label string
+
+	// CreatedAt is the Unix milliseconds timestamp when the record was created.
+	CreatedAt int64
+}
diff --git a/submitqueue/extension/conflict/tango/target_signature.go b/submitqueue/extension/conflict/tango/target_signature.go
new file mode 100644
index 000000000..fe6793c51
--- /dev/null
+++ b/submitqueue/extension/conflict/tango/target_signature.go
@@ -0,0 +1,45 @@
+// 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 tango
+
+// TargetSignature is the set of build targets a batch changes, as 64-bit IDs.
+// The whole record is immutable: (Queue, BatchID) is its identity and there is
+// no update path.
+type TargetSignature struct {
+	// Queue is the queue the batch belongs to. Unique together with BatchID.
+	Queue string
+
+	// BatchID is the canonical decimal batch identifier, unique within Queue.
+	BatchID string
+
+	// BaseRevision is the commit SHA the changed targets were computed against.
+	BaseRevision string
+
+	// Targets is sorted ascending by ID, with no duplicate IDs.
+	Targets []SignatureTarget
+
+	// CreatedAt is the Unix milliseconds timestamp when the record was created.
+	CreatedAt int64
+}
+
+// SignatureTarget is one changed build target in a TargetSignature.
+type SignatureTarget struct {
+	// ID is the 64-bit hash of the target's label.
+	ID uint64
+
+	// Distance is the distance from the nearest directly changed source in the
+	// reverse dependency graph; 0 means directly changed.
+	Distance int32
+}