diff --git a/BUILD.bazel b/BUILD.bazel
index 647896b6..f217e569 100644
--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -7,6 +7,8 @@ load("@gazelle//:def.bzl", "gazelle")
 # gazelle:exclude .claude
 
 # Resolve protobuf import ambiguities - use the actual protopb packages, not the proto aliases
+# gazelle:resolve go github.com/uber/submitqueue/api/base/change/protopb //api/base/change/protopb
+# gazelle:resolve go github.com/uber/submitqueue/api/base/mergestrategy/protopb //api/base/mergestrategy/protopb
 # gazelle:resolve go github.com/uber/submitqueue/api/submitqueue/gateway/protopb //api/submitqueue/gateway/protopb
 # gazelle:resolve go github.com/uber/submitqueue/api/submitqueue/orchestrator/protopb //api/submitqueue/orchestrator/protopb
 # gazelle:resolve go github.com/uber/submitqueue/api/stovepipe/gateway/protopb //api/stovepipe/gateway/protopb
diff --git a/MODULE.bazel b/MODULE.bazel
index d8c657fa..61bdeb2a 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -5,6 +5,12 @@ bazel_dep(name = "rules_go", version = "0.57.0")
 bazel_dep(name = "gazelle", version = "0.45.0")
 bazel_dep(name = "rules_proto", version = "7.1.0")
 
+# Direct dep so the well-known type proto_library targets (e.g.
+# @protobuf//:descriptor_proto, needed by the message queue topics option that
+# extends google.protobuf.MessageOptions) are visible by apparent name.
+# Toolchain resolution is unaffected: toolchains_protoc is registered first.
+bazel_dep(name = "protobuf", version = "29.1")
+
 # Use a prebuilt protoc binary instead of compiling protoc (and its abseil/upb
 # dependencies) from source on every cold build. Requires
 # --incompatible_enable_proto_toolchain_resolution (set in .bazelrc).
diff --git a/Makefile b/Makefile
index a1b413ef..49c110bf 100644
--- a/Makefile
+++ b/Makefile
@@ -31,7 +31,7 @@ GOIMPORTS_VERSION ?= v0.33.0
 # (the out_dir convention in tool/proto/BUILD.bazel) and copied back here. A
 # package may hold multiple .proto files (e.g. an RPC contract plus messagequeue
 # contracts); all generated stubs land in the same protopb/ dir.
-PROTO_PACKAGES = api/submitqueue/gateway api/submitqueue/orchestrator api/stovepipe/gateway api/stovepipe/orchestrator
+PROTO_PACKAGES = api/base/change api/base/mergestrategy api/base/messagequeue api/submitqueue/gateway api/submitqueue/orchestrator api/stovepipe/gateway api/stovepipe/orchestrator
 
 # Set REPO_ROOT for docker-compose
 export REPO_ROOT := $(shell pwd)
@@ -346,8 +346,10 @@ proto: ## Generate protobuf files from .proto definitions
 	@$(BAZEL) build //tool/proto:generated
 	@set -e; for pkg in $(PROTO_PACKAGES); do \
 	  out=$$(echo $$pkg | tr / _); \
+	  mkdir -p $$pkg/protopb; \
 	  for f in bazel-bin/tool/proto/$$out/*.go; do \
 	    cp -f $$f $$pkg/protopb/$$(basename $$f); \
+	    chmod 0644 $$pkg/protopb/$$(basename $$f); \
 	  done; \
 	done
 	@$(BAZEL) run @rules_go//go -- run golang.org/x/tools/cmd/goimports@$(GOIMPORTS_VERSION) -w $(addsuffix /protopb,$(PROTO_PACKAGES))
diff --git a/api/base/change/proto/BUILD.bazel b/api/base/change/proto/BUILD.bazel
new file mode 100644
index 00000000..972f2c7c
--- /dev/null
+++ b/api/base/change/proto/BUILD.bazel
@@ -0,0 +1,40 @@
+load("@rules_go//go:def.bzl", "go_library")
+load("@rules_go//proto:def.bzl", "go_proto_library")
+load("@rules_proto//proto:defs.bzl", "proto_library")
+
+exports_files(
+    ["change.proto"],
+    visibility = ["//tool/proto:__pkg__"],
+)
+
+proto_library(
+    name = "changepb_proto",
+    srcs = ["change.proto"],
+    visibility = ["//visibility:public"],
+)
+
+# keep
+go_proto_library(
+    name = "changepb_go_proto",
+    compilers = [
+        "@rules_go//proto:go_proto",
+        "@rules_go//proto:go_grpc_v2",
+    ],
+    importpath = "github.com/uber/submitqueue/api/base/change/proto",
+    proto = ":changepb_proto",
+    visibility = ["//visibility:public"],
+)
+
+go_library(
+    name = "proto",
+    embed = [":changepb_go_proto"],
+    importpath = "github.com/uber/submitqueue/api/base/change/proto",
+    visibility = ["//visibility:public"],
+)
+
+go_library(
+    name = "protopb",
+    embed = [":changepb_go_proto"],
+    importpath = "github.com/uber/submitqueue/api/base/change/protopb",
+    visibility = ["//visibility:public"],
+)
diff --git a/api/base/change/proto/change.proto b/api/base/change/proto/change.proto
new file mode 100644
index 00000000..a86a58f1
--- /dev/null
+++ b/api/base/change/proto/change.proto
@@ -0,0 +1,44 @@
+// Copyright (c) 2025 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.
+
+syntax = "proto3";
+
+package uber.base.change;
+
+option go_package = "github.com/uber/submitqueue/api/base/change/protopb";
+option java_multiple_files = true;
+option java_outer_classname = "ChangeProto";
+option java_package = "com.uber.submitqueue.base.change";
+
+// Change represents a code change identified by URIs from a code change provider
+// (e.g. a GitHub Pull Request, a Phabricator Diff, or a git commit). The provider
+// is extracted from the URI scheme.
+//
+// This is the shared wire contract for change identity, reused across SubmitQueue,
+// Stovepipe, and other repo-local domains — the proto-level analog of the
+// platform/base/change Go entity. Domains import it rather than redefining their own.
+message Change {
+    // URIs identifying the change(s) (RFC 3986 compliant). The scheme identifies the
+    // change provider, and the path contains provider-specific resource identifiers.
+    //
+    // Supported by default (other providers can be added):
+    //   GitHub PR:   "github://<org>/<repo>/pull/<pr>/<head_commit_sha>"
+    //                ("ghe"/"ghes" schemes for GitHub Enterprise)
+    //   git commit:  "git://<remote>/<repo>/<ref>/<commit_sha>"
+    //                (<ref> is a fully-qualified, percent-encoded git ref)
+    //
+    // The commit SHA must be the full 40-character lowercase hex SHA; abbreviated
+    // SHAs are rejected because downstream staleness checks compare by strict equality.
+    repeated string uris = 1;
+}
diff --git a/api/base/change/protopb/BUILD.bazel b/api/base/change/protopb/BUILD.bazel
new file mode 100644
index 00000000..716303de
--- /dev/null
+++ b/api/base/change/protopb/BUILD.bazel
@@ -0,0 +1,12 @@
+load("@rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "protopb",
+    srcs = ["change.pb.go"],
+    importpath = "github.com/uber/submitqueue/api/base/change/protopb",
+    visibility = ["//visibility:public"],
+    deps = [
+        "@org_golang_google_protobuf//reflect/protoreflect",
+        "@org_golang_google_protobuf//runtime/protoimpl",
+    ],
+)
diff --git a/api/base/change/protopb/change.pb.go b/api/base/change/protopb/change.pb.go
new file mode 100644
index 00000000..28416150
--- /dev/null
+++ b/api/base/change/protopb/change.pb.go
@@ -0,0 +1,157 @@
+// Copyright (c) 2025 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.
+
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// versions:
+// 	protoc-gen-go v1.36.10
+// 	protoc        v5.29.3
+// source: change.proto
+
+package protopb
+
+import (
+	reflect "reflect"
+	sync "sync"
+	unsafe "unsafe"
+
+	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
+	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
+)
+
+const (
+	// Verify that this generated code is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(20 - protoimpl.MinVersion)
+	// Verify that runtime/protoimpl is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
+)
+
+// Change represents a code change identified by URIs from a code change provider
+// (e.g. a GitHub Pull Request, a Phabricator Diff, or a git commit). The provider
+// is extracted from the URI scheme.
+//
+// This is the shared wire contract for change identity, reused across SubmitQueue,
+// Stovepipe, and other repo-local domains — the proto-level analog of the
+// platform/base/change Go entity. Domains import it rather than redefining their own.
+type Change struct {
+	state protoimpl.MessageState `protogen:"open.v1"`
+	// URIs identifying the change(s) (RFC 3986 compliant). The scheme identifies the
+	// change provider, and the path contains provider-specific resource identifiers.
+	//
+	// Supported by default (other providers can be added):
+	//
+	//	GitHub PR:   "github://<org>/<repo>/pull/<pr>/<head_commit_sha>"
+	//	             ("ghe"/"ghes" schemes for GitHub Enterprise)
+	//	git commit:  "git://<remote>/<repo>/<ref>/<commit_sha>"
+	//	             (<ref> is a fully-qualified, percent-encoded git ref)
+	//
+	// The commit SHA must be the full 40-character lowercase hex SHA; abbreviated
+	// SHAs are rejected because downstream staleness checks compare by strict equality.
+	Uris          []string `protobuf:"bytes,1,rep,name=uris,proto3" json:"uris,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *Change) Reset() {
+	*x = Change{}
+	mi := &file_change_proto_msgTypes[0]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *Change) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*Change) ProtoMessage() {}
+
+func (x *Change) ProtoReflect() protoreflect.Message {
+	mi := &file_change_proto_msgTypes[0]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use Change.ProtoReflect.Descriptor instead.
+func (*Change) Descriptor() ([]byte, []int) {
+	return file_change_proto_rawDescGZIP(), []int{0}
+}
+
+func (x *Change) GetUris() []string {
+	if x != nil {
+		return x.Uris
+	}
+	return nil
+}
+
+var File_change_proto protoreflect.FileDescriptor
+
+const file_change_proto_rawDesc = "" +
+	"\n" +
+	"\fchange.proto\x12\x10uber.base.change\"\x1c\n" +
+	"\x06Change\x12\x12\n" +
+	"\x04uris\x18\x01 \x03(\tR\x04urisBf\n" +
+	" com.uber.submitqueue.base.changeB\vChangeProtoP\x01Z3github.com/uber/submitqueue/api/base/change/protopbb\x06proto3"
+
+var (
+	file_change_proto_rawDescOnce sync.Once
+	file_change_proto_rawDescData []byte
+)
+
+func file_change_proto_rawDescGZIP() []byte {
+	file_change_proto_rawDescOnce.Do(func() {
+		file_change_proto_rawDescData = protoimpl.X.CompressGZIP(unsafe.Slice(unsafe.StringData(file_change_proto_rawDesc), len(file_change_proto_rawDesc)))
+	})
+	return file_change_proto_rawDescData
+}
+
+var file_change_proto_msgTypes = make([]protoimpl.MessageInfo, 1)
+var file_change_proto_goTypes = []any{
+	(*Change)(nil), // 0: uber.base.change.Change
+}
+var file_change_proto_depIdxs = []int32{
+	0, // [0:0] is the sub-list for method output_type
+	0, // [0:0] is the sub-list for method input_type
+	0, // [0:0] is the sub-list for extension type_name
+	0, // [0:0] is the sub-list for extension extendee
+	0, // [0:0] is the sub-list for field type_name
+}
+
+func init() { file_change_proto_init() }
+func file_change_proto_init() {
+	if File_change_proto != nil {
+		return
+	}
+	type x struct{}
+	out := protoimpl.TypeBuilder{
+		File: protoimpl.DescBuilder{
+			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
+			RawDescriptor: unsafe.Slice(unsafe.StringData(file_change_proto_rawDesc), len(file_change_proto_rawDesc)),
+			NumEnums:      0,
+			NumMessages:   1,
+			NumExtensions: 0,
+			NumServices:   0,
+		},
+		GoTypes:           file_change_proto_goTypes,
+		DependencyIndexes: file_change_proto_depIdxs,
+		MessageInfos:      file_change_proto_msgTypes,
+	}.Build()
+	File_change_proto = out.File
+	file_change_proto_goTypes = nil
+	file_change_proto_depIdxs = nil
+}
diff --git a/api/base/mergestrategy/proto/BUILD.bazel b/api/base/mergestrategy/proto/BUILD.bazel
new file mode 100644
index 00000000..cedde92c
--- /dev/null
+++ b/api/base/mergestrategy/proto/BUILD.bazel
@@ -0,0 +1,40 @@
+load("@rules_go//go:def.bzl", "go_library")
+load("@rules_go//proto:def.bzl", "go_proto_library")
+load("@rules_proto//proto:defs.bzl", "proto_library")
+
+exports_files(
+    ["mergestrategy.proto"],
+    visibility = ["//tool/proto:__pkg__"],
+)
+
+proto_library(
+    name = "mergestrategypb_proto",
+    srcs = ["mergestrategy.proto"],
+    visibility = ["//visibility:public"],
+)
+
+# keep
+go_proto_library(
+    name = "mergestrategypb_go_proto",
+    compilers = [
+        "@rules_go//proto:go_proto",
+        "@rules_go//proto:go_grpc_v2",
+    ],
+    importpath = "github.com/uber/submitqueue/api/base/mergestrategy/proto",
+    proto = ":mergestrategypb_proto",
+    visibility = ["//visibility:public"],
+)
+
+go_library(
+    name = "proto",
+    embed = [":mergestrategypb_go_proto"],
+    importpath = "github.com/uber/submitqueue/api/base/mergestrategy/proto",
+    visibility = ["//visibility:public"],
+)
+
+go_library(
+    name = "protopb",
+    embed = [":mergestrategypb_go_proto"],
+    importpath = "github.com/uber/submitqueue/api/base/mergestrategy/protopb",
+    visibility = ["//visibility:public"],
+)
diff --git a/api/base/mergestrategy/proto/mergestrategy.proto b/api/base/mergestrategy/proto/mergestrategy.proto
new file mode 100644
index 00000000..0769ba9d
--- /dev/null
+++ b/api/base/mergestrategy/proto/mergestrategy.proto
@@ -0,0 +1,39 @@
+// Copyright (c) 2025 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.
+
+syntax = "proto3";
+
+package uber.base.mergestrategy;
+
+option go_package = "github.com/uber/submitqueue/api/base/mergestrategy/protopb";
+option java_multiple_files = true;
+option java_outer_classname = "MergeStrategyProto";
+option java_package = "com.uber.submitqueue.base.mergestrategy";
+
+// Strategy defines the possible source control integration methods — how a change
+// is integrated into the target branch.
+//
+// This is the shared wire contract for merge strategy, reused across SubmitQueue
+// and other repo-local domains — the proto-level analog of the
+// platform/base/mergestrategy Go entity. Domains import it rather than redefining their own.
+enum Strategy {
+    // Default strategy (let the server decide based on configuration).
+    DEFAULT = 0;
+    // Rebase commits onto the target branch before landing.
+    REBASE = 1;
+    // Same as REBASE but squash commits into a single commit before rebase.
+    SQUASH_REBASE = 2;
+    // Merge commits into the target branch by creating a separate merge commit, preserving commit history along with hashes.
+    MERGE = 3;
+}
diff --git a/api/base/mergestrategy/protopb/BUILD.bazel b/api/base/mergestrategy/protopb/BUILD.bazel
new file mode 100644
index 00000000..7340c8c2
--- /dev/null
+++ b/api/base/mergestrategy/protopb/BUILD.bazel
@@ -0,0 +1,12 @@
+load("@rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "protopb",
+    srcs = ["mergestrategy.pb.go"],
+    importpath = "github.com/uber/submitqueue/api/base/mergestrategy/protopb",
+    visibility = ["//visibility:public"],
+    deps = [
+        "@org_golang_google_protobuf//reflect/protoreflect",
+        "@org_golang_google_protobuf//runtime/protoimpl",
+    ],
+)
diff --git a/api/base/mergestrategy/protopb/mergestrategy.pb.go b/api/base/mergestrategy/protopb/mergestrategy.pb.go
new file mode 100644
index 00000000..7546b555
--- /dev/null
+++ b/api/base/mergestrategy/protopb/mergestrategy.pb.go
@@ -0,0 +1,160 @@
+// Copyright (c) 2025 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.
+
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// versions:
+// 	protoc-gen-go v1.36.10
+// 	protoc        v5.29.3
+// source: mergestrategy.proto
+
+package protopb
+
+import (
+	reflect "reflect"
+	sync "sync"
+	unsafe "unsafe"
+
+	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
+	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
+)
+
+const (
+	// Verify that this generated code is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(20 - protoimpl.MinVersion)
+	// Verify that runtime/protoimpl is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
+)
+
+// Strategy defines the possible source control integration methods — how a change
+// is integrated into the target branch.
+//
+// This is the shared wire contract for merge strategy, reused across SubmitQueue
+// and other repo-local domains — the proto-level analog of the
+// platform/base/mergestrategy Go entity. Domains import it rather than redefining their own.
+type Strategy int32
+
+const (
+	// Default strategy (let the server decide based on configuration).
+	Strategy_DEFAULT Strategy = 0
+	// Rebase commits onto the target branch before landing.
+	Strategy_REBASE Strategy = 1
+	// Same as REBASE but squash commits into a single commit before rebase.
+	Strategy_SQUASH_REBASE Strategy = 2
+	// Merge commits into the target branch by creating a separate merge commit, preserving commit history along with hashes.
+	Strategy_MERGE Strategy = 3
+)
+
+// Enum value maps for Strategy.
+var (
+	Strategy_name = map[int32]string{
+		0: "DEFAULT",
+		1: "REBASE",
+		2: "SQUASH_REBASE",
+		3: "MERGE",
+	}
+	Strategy_value = map[string]int32{
+		"DEFAULT":       0,
+		"REBASE":        1,
+		"SQUASH_REBASE": 2,
+		"MERGE":         3,
+	}
+)
+
+func (x Strategy) Enum() *Strategy {
+	p := new(Strategy)
+	*p = x
+	return p
+}
+
+func (x Strategy) String() string {
+	return protoimpl.X.EnumStringOf(x.Descriptor(), protoreflect.EnumNumber(x))
+}
+
+func (Strategy) Descriptor() protoreflect.EnumDescriptor {
+	return file_mergestrategy_proto_enumTypes[0].Descriptor()
+}
+
+func (Strategy) Type() protoreflect.EnumType {
+	return &file_mergestrategy_proto_enumTypes[0]
+}
+
+func (x Strategy) Number() protoreflect.EnumNumber {
+	return protoreflect.EnumNumber(x)
+}
+
+// Deprecated: Use Strategy.Descriptor instead.
+func (Strategy) EnumDescriptor() ([]byte, []int) {
+	return file_mergestrategy_proto_rawDescGZIP(), []int{0}
+}
+
+var File_mergestrategy_proto protoreflect.FileDescriptor
+
+const file_mergestrategy_proto_rawDesc = "" +
+	"\n" +
+	"\x13mergestrategy.proto\x12\x17uber.base.mergestrategy*A\n" +
+	"\bStrategy\x12\v\n" +
+	"\aDEFAULT\x10\x00\x12\n" +
+	"\n" +
+	"\x06REBASE\x10\x01\x12\x11\n" +
+	"\rSQUASH_REBASE\x10\x02\x12\t\n" +
+	"\x05MERGE\x10\x03B{\n" +
+	"'com.uber.submitqueue.base.mergestrategyB\x12MergeStrategyProtoP\x01Z:github.com/uber/submitqueue/api/base/mergestrategy/protopbb\x06proto3"
+
+var (
+	file_mergestrategy_proto_rawDescOnce sync.Once
+	file_mergestrategy_proto_rawDescData []byte
+)
+
+func file_mergestrategy_proto_rawDescGZIP() []byte {
+	file_mergestrategy_proto_rawDescOnce.Do(func() {
+		file_mergestrategy_proto_rawDescData = protoimpl.X.CompressGZIP(unsafe.Slice(unsafe.StringData(file_mergestrategy_proto_rawDesc), len(file_mergestrategy_proto_rawDesc)))
+	})
+	return file_mergestrategy_proto_rawDescData
+}
+
+var file_mergestrategy_proto_enumTypes = make([]protoimpl.EnumInfo, 1)
+var file_mergestrategy_proto_goTypes = []any{
+	(Strategy)(0), // 0: uber.base.mergestrategy.Strategy
+}
+var file_mergestrategy_proto_depIdxs = []int32{
+	0, // [0:0] is the sub-list for method output_type
+	0, // [0:0] is the sub-list for method input_type
+	0, // [0:0] is the sub-list for extension type_name
+	0, // [0:0] is the sub-list for extension extendee
+	0, // [0:0] is the sub-list for field type_name
+}
+
+func init() { file_mergestrategy_proto_init() }
+func file_mergestrategy_proto_init() {
+	if File_mergestrategy_proto != nil {
+		return
+	}
+	type x struct{}
+	out := protoimpl.TypeBuilder{
+		File: protoimpl.DescBuilder{
+			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
+			RawDescriptor: unsafe.Slice(unsafe.StringData(file_mergestrategy_proto_rawDesc), len(file_mergestrategy_proto_rawDesc)),
+			NumEnums:      1,
+			NumMessages:   0,
+			NumExtensions: 0,
+			NumServices:   0,
+		},
+		GoTypes:           file_mergestrategy_proto_goTypes,
+		DependencyIndexes: file_mergestrategy_proto_depIdxs,
+		EnumInfos:         file_mergestrategy_proto_enumTypes,
+	}.Build()
+	File_mergestrategy_proto = out.File
+	file_mergestrategy_proto_goTypes = nil
+	file_mergestrategy_proto_depIdxs = nil
+}
diff --git a/api/base/messagequeue/proto/BUILD.bazel b/api/base/messagequeue/proto/BUILD.bazel
new file mode 100644
index 00000000..09d957d3
--- /dev/null
+++ b/api/base/messagequeue/proto/BUILD.bazel
@@ -0,0 +1,41 @@
+load("@rules_go//go:def.bzl", "go_library")
+load("@rules_go//proto:def.bzl", "go_proto_library")
+load("@rules_proto//proto:defs.bzl", "proto_library")
+
+exports_files(
+    ["messagequeue.proto"],
+    visibility = ["//tool/proto:__pkg__"],
+)
+
+proto_library(
+    name = "messagequeuepb_proto",
+    srcs = ["messagequeue.proto"],
+    visibility = ["//visibility:public"],
+    deps = ["@protobuf//:descriptor_proto"],
+)
+
+# keep
+go_proto_library(
+    name = "messagequeuepb_go_proto",
+    compilers = [
+        "@rules_go//proto:go_proto",
+        "@rules_go//proto:go_grpc_v2",
+    ],
+    importpath = "github.com/uber/submitqueue/api/base/messagequeue/proto",
+    proto = ":messagequeuepb_proto",
+    visibility = ["//visibility:public"],
+)
+
+go_library(
+    name = "proto",
+    embed = [":messagequeuepb_go_proto"],
+    importpath = "github.com/uber/submitqueue/api/base/messagequeue/proto",
+    visibility = ["//visibility:public"],
+)
+
+go_library(
+    name = "protopb",
+    embed = [":messagequeuepb_go_proto"],
+    importpath = "github.com/uber/submitqueue/api/base/messagequeue/protopb",
+    visibility = ["//visibility:public"],
+)
diff --git a/api/base/messagequeue/proto/messagequeue.proto b/api/base/messagequeue/proto/messagequeue.proto
new file mode 100644
index 00000000..78d2e096
--- /dev/null
+++ b/api/base/messagequeue/proto/messagequeue.proto
@@ -0,0 +1,40 @@
+// Copyright (c) 2025 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.
+
+syntax = "proto3";
+
+package uber.base.messagequeue;
+
+import "google/protobuf/descriptor.proto";
+
+option go_package = "github.com/uber/submitqueue/api/base/messagequeue/protopb";
+option java_multiple_files = true;
+option java_outer_classname = "MessageQueueProto";
+option java_package = "com.uber.submitqueue.base.messagequeue";
+
+// Topic-binding option: the shared wire contract annotation that binds a queue
+// payload message to the topic(s) that carry it. A message queue payload — in
+// any domain — annotates itself with the canonical wire topic name(s), making
+// the topic-to-payload binding part of the language-neutral proto contract
+// rather than out-of-band Go wiring. A single payload may list several topics
+// (one shape can serve a queue pair, e.g. a dry-run check and a committing
+// merge). Domains import this rather than redefining their own.
+extend google.protobuf.MessageOptions {
+    // topics are the canonical wire topic names that carry this message. The
+    // reverse index (topic -> message) is derivable; this is the single source
+    // of truth. The strings match the consumer.TopicKey values used in Go
+    // wiring. Extension field 50001 is in the 50000-99999 range reserved for
+    // organization-internal use.
+    repeated string topics = 50001;
+}
diff --git a/api/base/messagequeue/protopb/BUILD.bazel b/api/base/messagequeue/protopb/BUILD.bazel
new file mode 100644
index 00000000..0e0e20c9
--- /dev/null
+++ b/api/base/messagequeue/protopb/BUILD.bazel
@@ -0,0 +1,13 @@
+load("@rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "protopb",
+    srcs = ["messagequeue.pb.go"],
+    importpath = "github.com/uber/submitqueue/api/base/messagequeue/protopb",
+    visibility = ["//visibility:public"],
+    deps = [
+        "@org_golang_google_protobuf//reflect/protoreflect",
+        "@org_golang_google_protobuf//runtime/protoimpl",
+        "@org_golang_google_protobuf//types/descriptorpb",
+    ],
+)
diff --git a/api/base/messagequeue/protopb/messagequeue.pb.go b/api/base/messagequeue/protopb/messagequeue.pb.go
new file mode 100644
index 00000000..ee5767f5
--- /dev/null
+++ b/api/base/messagequeue/protopb/messagequeue.pb.go
@@ -0,0 +1,104 @@
+// Copyright (c) 2025 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.
+
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// versions:
+// 	protoc-gen-go v1.36.10
+// 	protoc        v5.29.3
+// source: messagequeue.proto
+
+package protopb
+
+import (
+	reflect "reflect"
+	unsafe "unsafe"
+
+	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
+	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
+	descriptorpb "google.golang.org/protobuf/types/descriptorpb"
+)
+
+const (
+	// Verify that this generated code is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(20 - protoimpl.MinVersion)
+	// Verify that runtime/protoimpl is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
+)
+
+var file_messagequeue_proto_extTypes = []protoimpl.ExtensionInfo{
+	{
+		ExtendedType:  (*descriptorpb.MessageOptions)(nil),
+		ExtensionType: ([]string)(nil),
+		Field:         50001,
+		Name:          "uber.base.messagequeue.topics",
+		Tag:           "bytes,50001,rep,name=topics",
+		Filename:      "messagequeue.proto",
+	},
+}
+
+// Extension fields to descriptorpb.MessageOptions.
+var (
+	// topics are the canonical wire topic names that carry this message. The
+	// reverse index (topic -> message) is derivable; this is the single source
+	// of truth. The strings match the consumer.TopicKey values used in Go
+	// wiring. Extension field 50001 is in the 50000-99999 range reserved for
+	// organization-internal use.
+	//
+	// repeated string topics = 50001;
+	E_Topics = &file_messagequeue_proto_extTypes[0]
+)
+
+var File_messagequeue_proto protoreflect.FileDescriptor
+
+const file_messagequeue_proto_rawDesc = "" +
+	"\n" +
+	"\x12messagequeue.proto\x12\x16uber.base.messagequeue\x1a google/protobuf/descriptor.proto:9\n" +
+	"\x06topics\x12\x1f.google.protobuf.MessageOptions\x18ц\x03 \x03(\tR\x06topicsBx\n" +
+	"&com.uber.submitqueue.base.messagequeueB\x11MessageQueueProtoP\x01Z9github.com/uber/submitqueue/api/base/messagequeue/protopbb\x06proto3"
+
+var file_messagequeue_proto_goTypes = []any{
+	(*descriptorpb.MessageOptions)(nil), // 0: google.protobuf.MessageOptions
+}
+var file_messagequeue_proto_depIdxs = []int32{
+	0, // 0: uber.base.messagequeue.topics:extendee -> google.protobuf.MessageOptions
+	1, // [1:1] is the sub-list for method output_type
+	1, // [1:1] is the sub-list for method input_type
+	1, // [1:1] is the sub-list for extension type_name
+	0, // [0:1] is the sub-list for extension extendee
+	0, // [0:0] is the sub-list for field type_name
+}
+
+func init() { file_messagequeue_proto_init() }
+func file_messagequeue_proto_init() {
+	if File_messagequeue_proto != nil {
+		return
+	}
+	type x struct{}
+	out := protoimpl.TypeBuilder{
+		File: protoimpl.DescBuilder{
+			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
+			RawDescriptor: unsafe.Slice(unsafe.StringData(file_messagequeue_proto_rawDesc), len(file_messagequeue_proto_rawDesc)),
+			NumEnums:      0,
+			NumMessages:   0,
+			NumExtensions: 1,
+			NumServices:   0,
+		},
+		GoTypes:           file_messagequeue_proto_goTypes,
+		DependencyIndexes: file_messagequeue_proto_depIdxs,
+		ExtensionInfos:    file_messagequeue_proto_extTypes,
+	}.Build()
+	File_messagequeue_proto = out.File
+	file_messagequeue_proto_goTypes = nil
+	file_messagequeue_proto_depIdxs = nil
+}
diff --git a/api/submitqueue/gateway/proto/BUILD.bazel b/api/submitqueue/gateway/proto/BUILD.bazel
index 7800da89..9ccb5a7f 100644
--- a/api/submitqueue/gateway/proto/BUILD.bazel
+++ b/api/submitqueue/gateway/proto/BUILD.bazel
@@ -11,6 +11,10 @@ proto_library(
     name = "gatewaypb_proto",
     srcs = ["gateway.proto"],
     visibility = ["//visibility:public"],
+    deps = [
+        "//api/base/change/proto:changepb_proto",
+        "//api/base/mergestrategy/proto:mergestrategypb_proto",
+    ],
 )
 
 # keep
@@ -23,6 +27,11 @@ go_proto_library(
     importpath = "github.com/uber/submitqueue/api/submitqueue/gateway/proto",
     proto = ":gatewaypb_proto",
     visibility = ["//visibility:public"],
+    # keep
+    deps = [
+        "//api/base/change/proto:changepb_go_proto",
+        "//api/base/mergestrategy/proto:mergestrategypb_go_proto",
+    ],
 )
 
 go_library(
diff --git a/api/submitqueue/gateway/proto/gateway.proto b/api/submitqueue/gateway/proto/gateway.proto
index 3b7a0fac..244f7b43 100644
--- a/api/submitqueue/gateway/proto/gateway.proto
+++ b/api/submitqueue/gateway/proto/gateway.proto
@@ -21,6 +21,9 @@ option java_multiple_files = true;
 option java_outer_classname = "GatewayProto";
 option java_package = "com.uber.submitqueue.gateway";
 
+import "api/base/change/proto/change.proto";
+import "api/base/mergestrategy/proto/mergestrategy.proto";
+
 // ***************
 // API domain definitions.
 // ***************
@@ -43,47 +46,18 @@ message PingResponse {
     string hostname = 4;
 }
 
-// Strategy defines the possible source control integration methods
-enum Strategy {
-    // Default strategy (let server decide based on configuration)
-    DEFAULT = 0;
-    // Rebase commits onto target branch before landing
-    REBASE = 1;
-    // Same as REBASE but squash commits into a single commit before rebase
-    SQUASH_REBASE = 2;
-    // Merge commits into the target branch by creating a separate merge commit, preserving the commit history along with hashes
-    MERGE = 3;
-}
-
-// Change represents a code change identified by URIs from a code change provider (e.g., GitHub Pull Request, Phabricator Diff).
-// The provider is extracted from the URI scheme.
-message Change {
-    // URIs identifying the change(s) to land (RFC 3986 compliant).
-    // The scheme identifies the change provider, and the path contains provider-specific resource identifiers.
-    //
-    // GitHub is supported by default (though other providers can be added):
-    //   Template: "<scheme>://<org>/<repo>/pull/<pr>/<head_commit_sha>"
-    //   Example:  "github://uber/submitqueue/pull/123/c3a4d5e6f7890123456789abcdef0123456789ab"
-    //   Schemes:  "github" (github.com), "ghe" (GitHub Enterprise), "ghes" (GitHub Enterprise Server).
-    //   The path mirrors the canonical PR URL so URIs can be constructed by trivial substitution.
-    //   The head commit SHA must be the full 40-character lowercase hex SHA of the PR's head commit,
-    //   as returned by GitHub's API (graphql `headRefOid`). Abbreviated SHAs are rejected because
-    //   the staleness check downstream compares with strict string equality against the full SHA.
-    //
-    // SubmitQueue guarantees changes are landed in order with no other changes in between.
-    // SubmitQueue does not guarantee each change is individually valid, but produces a validity marker on such changes.
-    // The user is responsible for including all changes in a stack in order, starting from the earliest change.
-    repeated string uris = 1;
-}
-
 // LandRequest defines a request to land (merge into target branch of the source control repository) a set of code changes.
+//
+// SubmitQueue guarantees changes are landed in order with no other changes in between.
+// SubmitQueue does not guarantee each change is individually valid, but produces a validity marker on such changes.
+// The user is responsible for including all changes in a stack in order, starting from the earliest change.
 message LandRequest {
     // Name of the queue processing the land request. The queue should be defined in the configuration, otherwise an error is returned.
     string queue = 1;
     // Change (such as a pull request) to land into the target branch. Target branch is defined by the queue configuration.
-    Change change = 2;
+    uber.base.change.Change change = 2;
     // Source control integration strategy to use for this land operation. If not specified, the default queue strategy is used.
-    Strategy strategy = 4;
+    uber.base.mergestrategy.Strategy strategy = 4;
 }
 
 // LandResponse defines the response to a land request.
diff --git a/api/submitqueue/gateway/protopb/BUILD.bazel b/api/submitqueue/gateway/protopb/BUILD.bazel
index 8431100a..1a3eb4b8 100644
--- a/api/submitqueue/gateway/protopb/BUILD.bazel
+++ b/api/submitqueue/gateway/protopb/BUILD.bazel
@@ -10,6 +10,8 @@ go_library(
     importpath = "github.com/uber/submitqueue/api/submitqueue/gateway/protopb",
     visibility = ["//visibility:public"],
     deps = [
+        "//api/base/change/protopb",
+        "//api/base/mergestrategy/protopb",
         "@org_golang_google_grpc//:grpc",
         "@org_golang_google_grpc//codes",
         "@org_golang_google_grpc//status",
diff --git a/api/submitqueue/gateway/protopb/gateway.pb.go b/api/submitqueue/gateway/protopb/gateway.pb.go
index b4886ff6..20c020f3 100644
--- a/api/submitqueue/gateway/protopb/gateway.pb.go
+++ b/api/submitqueue/gateway/protopb/gateway.pb.go
@@ -25,6 +25,8 @@ import (
 	sync "sync"
 	unsafe "unsafe"
 
+	protopb "github.com/uber/submitqueue/api/base/change/protopb"
+	protopb1 "github.com/uber/submitqueue/api/base/mergestrategy/protopb"
 	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
 	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
 )
@@ -36,63 +38,6 @@ const (
 	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
 )
 
-// Strategy defines the possible source control integration methods
-type Strategy int32
-
-const (
-	// Default strategy (let server decide based on configuration)
-	Strategy_DEFAULT Strategy = 0
-	// Rebase commits onto target branch before landing
-	Strategy_REBASE Strategy = 1
-	// Same as REBASE but squash commits into a single commit before rebase
-	Strategy_SQUASH_REBASE Strategy = 2
-	// Merge commits into the target branch by creating a separate merge commit, preserving the commit history along with hashes
-	Strategy_MERGE Strategy = 3
-)
-
-// Enum value maps for Strategy.
-var (
-	Strategy_name = map[int32]string{
-		0: "DEFAULT",
-		1: "REBASE",
-		2: "SQUASH_REBASE",
-		3: "MERGE",
-	}
-	Strategy_value = map[string]int32{
-		"DEFAULT":       0,
-		"REBASE":        1,
-		"SQUASH_REBASE": 2,
-		"MERGE":         3,
-	}
-)
-
-func (x Strategy) Enum() *Strategy {
-	p := new(Strategy)
-	*p = x
-	return p
-}
-
-func (x Strategy) String() string {
-	return protoimpl.X.EnumStringOf(x.Descriptor(), protoreflect.EnumNumber(x))
-}
-
-func (Strategy) Descriptor() protoreflect.EnumDescriptor {
-	return file_gateway_proto_enumTypes[0].Descriptor()
-}
-
-func (Strategy) Type() protoreflect.EnumType {
-	return &file_gateway_proto_enumTypes[0]
-}
-
-func (x Strategy) Number() protoreflect.EnumNumber {
-	return protoreflect.EnumNumber(x)
-}
-
-// Deprecated: Use Strategy.Descriptor instead.
-func (Strategy) EnumDescriptor() ([]byte, []int) {
-	return file_gateway_proto_rawDescGZIP(), []int{0}
-}
-
 // PingRequest is the request for the Ping method
 type PingRequest struct {
 	state protoimpl.MessageState `protogen:"open.v1"`
@@ -212,84 +157,26 @@ func (x *PingResponse) GetHostname() string {
 	return ""
 }
 
-// Change represents a code change identified by URIs from a code change provider (e.g., GitHub Pull Request, Phabricator Diff).
-// The provider is extracted from the URI scheme.
-type Change struct {
-	state protoimpl.MessageState `protogen:"open.v1"`
-	// URIs identifying the change(s) to land (RFC 3986 compliant).
-	// The scheme identifies the change provider, and the path contains provider-specific resource identifiers.
-	//
-	// GitHub is supported by default (though other providers can be added):
-	//
-	//	Template: "<scheme>://<org>/<repo>/pull/<pr>/<head_commit_sha>"
-	//	Example:  "github://uber/submitqueue/pull/123/c3a4d5e6f7890123456789abcdef0123456789ab"
-	//	Schemes:  "github" (github.com), "ghe" (GitHub Enterprise), "ghes" (GitHub Enterprise Server).
-	//	The path mirrors the canonical PR URL so URIs can be constructed by trivial substitution.
-	//	The head commit SHA must be the full 40-character lowercase hex SHA of the PR's head commit,
-	//	as returned by GitHub's API (graphql `headRefOid`). Abbreviated SHAs are rejected because
-	//	the staleness check downstream compares with strict string equality against the full SHA.
-	//
-	// SubmitQueue guarantees changes are landed in order with no other changes in between.
-	// SubmitQueue does not guarantee each change is individually valid, but produces a validity marker on such changes.
-	// The user is responsible for including all changes in a stack in order, starting from the earliest change.
-	Uris          []string `protobuf:"bytes,1,rep,name=uris,proto3" json:"uris,omitempty"`
-	unknownFields protoimpl.UnknownFields
-	sizeCache     protoimpl.SizeCache
-}
-
-func (x *Change) Reset() {
-	*x = Change{}
-	mi := &file_gateway_proto_msgTypes[2]
-	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-	ms.StoreMessageInfo(mi)
-}
-
-func (x *Change) String() string {
-	return protoimpl.X.MessageStringOf(x)
-}
-
-func (*Change) ProtoMessage() {}
-
-func (x *Change) ProtoReflect() protoreflect.Message {
-	mi := &file_gateway_proto_msgTypes[2]
-	if x != nil {
-		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-		if ms.LoadMessageInfo() == nil {
-			ms.StoreMessageInfo(mi)
-		}
-		return ms
-	}
-	return mi.MessageOf(x)
-}
-
-// Deprecated: Use Change.ProtoReflect.Descriptor instead.
-func (*Change) Descriptor() ([]byte, []int) {
-	return file_gateway_proto_rawDescGZIP(), []int{2}
-}
-
-func (x *Change) GetUris() []string {
-	if x != nil {
-		return x.Uris
-	}
-	return nil
-}
-
 // LandRequest defines a request to land (merge into target branch of the source control repository) a set of code changes.
+//
+// SubmitQueue guarantees changes are landed in order with no other changes in between.
+// SubmitQueue does not guarantee each change is individually valid, but produces a validity marker on such changes.
+// The user is responsible for including all changes in a stack in order, starting from the earliest change.
 type LandRequest struct {
 	state protoimpl.MessageState `protogen:"open.v1"`
 	// Name of the queue processing the land request. The queue should be defined in the configuration, otherwise an error is returned.
 	Queue string `protobuf:"bytes,1,opt,name=queue,proto3" json:"queue,omitempty"`
 	// Change (such as a pull request) to land into the target branch. Target branch is defined by the queue configuration.
-	Change *Change `protobuf:"bytes,2,opt,name=change,proto3" json:"change,omitempty"`
+	Change *protopb.Change `protobuf:"bytes,2,opt,name=change,proto3" json:"change,omitempty"`
 	// Source control integration strategy to use for this land operation. If not specified, the default queue strategy is used.
-	Strategy      Strategy `protobuf:"varint,4,opt,name=strategy,proto3,enum=uber.submitqueue.gateway.Strategy" json:"strategy,omitempty"`
+	Strategy      protopb1.Strategy `protobuf:"varint,4,opt,name=strategy,proto3,enum=uber.base.mergestrategy.Strategy" json:"strategy,omitempty"`
 	unknownFields protoimpl.UnknownFields
 	sizeCache     protoimpl.SizeCache
 }
 
 func (x *LandRequest) Reset() {
 	*x = LandRequest{}
-	mi := &file_gateway_proto_msgTypes[3]
+	mi := &file_gateway_proto_msgTypes[2]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -301,7 +188,7 @@ func (x *LandRequest) String() string {
 func (*LandRequest) ProtoMessage() {}
 
 func (x *LandRequest) ProtoReflect() protoreflect.Message {
-	mi := &file_gateway_proto_msgTypes[3]
+	mi := &file_gateway_proto_msgTypes[2]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -314,7 +201,7 @@ func (x *LandRequest) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use LandRequest.ProtoReflect.Descriptor instead.
 func (*LandRequest) Descriptor() ([]byte, []int) {
-	return file_gateway_proto_rawDescGZIP(), []int{3}
+	return file_gateway_proto_rawDescGZIP(), []int{2}
 }
 
 func (x *LandRequest) GetQueue() string {
@@ -324,18 +211,18 @@ func (x *LandRequest) GetQueue() string {
 	return ""
 }
 
-func (x *LandRequest) GetChange() *Change {
+func (x *LandRequest) GetChange() *protopb.Change {
 	if x != nil {
 		return x.Change
 	}
 	return nil
 }
 
-func (x *LandRequest) GetStrategy() Strategy {
+func (x *LandRequest) GetStrategy() protopb1.Strategy {
 	if x != nil {
 		return x.Strategy
 	}
-	return Strategy_DEFAULT
+	return protopb1.Strategy(0)
 }
 
 // LandResponse defines the response to a land request.
@@ -349,7 +236,7 @@ type LandResponse struct {
 
 func (x *LandResponse) Reset() {
 	*x = LandResponse{}
-	mi := &file_gateway_proto_msgTypes[4]
+	mi := &file_gateway_proto_msgTypes[3]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -361,7 +248,7 @@ func (x *LandResponse) String() string {
 func (*LandResponse) ProtoMessage() {}
 
 func (x *LandResponse) ProtoReflect() protoreflect.Message {
-	mi := &file_gateway_proto_msgTypes[4]
+	mi := &file_gateway_proto_msgTypes[3]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -374,7 +261,7 @@ func (x *LandResponse) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use LandResponse.ProtoReflect.Descriptor instead.
 func (*LandResponse) Descriptor() ([]byte, []int) {
-	return file_gateway_proto_rawDescGZIP(), []int{4}
+	return file_gateway_proto_rawDescGZIP(), []int{3}
 }
 
 func (x *LandResponse) GetSqid() string {
@@ -397,7 +284,7 @@ type CancelRequest struct {
 
 func (x *CancelRequest) Reset() {
 	*x = CancelRequest{}
-	mi := &file_gateway_proto_msgTypes[5]
+	mi := &file_gateway_proto_msgTypes[4]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -409,7 +296,7 @@ func (x *CancelRequest) String() string {
 func (*CancelRequest) ProtoMessage() {}
 
 func (x *CancelRequest) ProtoReflect() protoreflect.Message {
-	mi := &file_gateway_proto_msgTypes[5]
+	mi := &file_gateway_proto_msgTypes[4]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -422,7 +309,7 @@ func (x *CancelRequest) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use CancelRequest.ProtoReflect.Descriptor instead.
 func (*CancelRequest) Descriptor() ([]byte, []int) {
-	return file_gateway_proto_rawDescGZIP(), []int{5}
+	return file_gateway_proto_rawDescGZIP(), []int{4}
 }
 
 func (x *CancelRequest) GetSqid() string {
@@ -452,7 +339,7 @@ type CancelResponse struct {
 
 func (x *CancelResponse) Reset() {
 	*x = CancelResponse{}
-	mi := &file_gateway_proto_msgTypes[6]
+	mi := &file_gateway_proto_msgTypes[5]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -464,7 +351,7 @@ func (x *CancelResponse) String() string {
 func (*CancelResponse) ProtoMessage() {}
 
 func (x *CancelResponse) ProtoReflect() protoreflect.Message {
-	mi := &file_gateway_proto_msgTypes[6]
+	mi := &file_gateway_proto_msgTypes[5]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -477,7 +364,7 @@ func (x *CancelResponse) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use CancelResponse.ProtoReflect.Descriptor instead.
 func (*CancelResponse) Descriptor() ([]byte, []int) {
-	return file_gateway_proto_rawDescGZIP(), []int{6}
+	return file_gateway_proto_rawDescGZIP(), []int{5}
 }
 
 // StatusRequest defines a request to look up the current status of a previously submitted request.
@@ -491,7 +378,7 @@ type StatusRequest struct {
 
 func (x *StatusRequest) Reset() {
 	*x = StatusRequest{}
-	mi := &file_gateway_proto_msgTypes[7]
+	mi := &file_gateway_proto_msgTypes[6]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -503,7 +390,7 @@ func (x *StatusRequest) String() string {
 func (*StatusRequest) ProtoMessage() {}
 
 func (x *StatusRequest) ProtoReflect() protoreflect.Message {
-	mi := &file_gateway_proto_msgTypes[7]
+	mi := &file_gateway_proto_msgTypes[6]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -516,7 +403,7 @@ func (x *StatusRequest) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use StatusRequest.ProtoReflect.Descriptor instead.
 func (*StatusRequest) Descriptor() ([]byte, []int) {
-	return file_gateway_proto_rawDescGZIP(), []int{7}
+	return file_gateway_proto_rawDescGZIP(), []int{6}
 }
 
 func (x *StatusRequest) GetSqid() string {
@@ -543,7 +430,7 @@ type StatusResponse struct {
 
 func (x *StatusResponse) Reset() {
 	*x = StatusResponse{}
-	mi := &file_gateway_proto_msgTypes[8]
+	mi := &file_gateway_proto_msgTypes[7]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -555,7 +442,7 @@ func (x *StatusResponse) String() string {
 func (*StatusResponse) ProtoMessage() {}
 
 func (x *StatusResponse) ProtoReflect() protoreflect.Message {
-	mi := &file_gateway_proto_msgTypes[8]
+	mi := &file_gateway_proto_msgTypes[7]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -568,7 +455,7 @@ func (x *StatusResponse) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use StatusResponse.ProtoReflect.Descriptor instead.
 func (*StatusResponse) Descriptor() ([]byte, []int) {
-	return file_gateway_proto_rawDescGZIP(), []int{8}
+	return file_gateway_proto_rawDescGZIP(), []int{7}
 }
 
 func (x *StatusResponse) GetStatus() string {
@@ -603,7 +490,7 @@ type Error struct {
 
 func (x *Error) Reset() {
 	*x = Error{}
-	mi := &file_gateway_proto_msgTypes[9]
+	mi := &file_gateway_proto_msgTypes[8]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -615,7 +502,7 @@ func (x *Error) String() string {
 func (*Error) ProtoMessage() {}
 
 func (x *Error) ProtoReflect() protoreflect.Message {
-	mi := &file_gateway_proto_msgTypes[9]
+	mi := &file_gateway_proto_msgTypes[8]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -628,7 +515,7 @@ func (x *Error) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use Error.ProtoReflect.Descriptor instead.
 func (*Error) Descriptor() ([]byte, []int) {
-	return file_gateway_proto_rawDescGZIP(), []int{9}
+	return file_gateway_proto_rawDescGZIP(), []int{8}
 }
 
 func (x *Error) GetMessage() string {
@@ -651,7 +538,7 @@ type UnrecognizedQueueError struct {
 
 func (x *UnrecognizedQueueError) Reset() {
 	*x = UnrecognizedQueueError{}
-	mi := &file_gateway_proto_msgTypes[10]
+	mi := &file_gateway_proto_msgTypes[9]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -663,7 +550,7 @@ func (x *UnrecognizedQueueError) String() string {
 func (*UnrecognizedQueueError) ProtoMessage() {}
 
 func (x *UnrecognizedQueueError) ProtoReflect() protoreflect.Message {
-	mi := &file_gateway_proto_msgTypes[10]
+	mi := &file_gateway_proto_msgTypes[9]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -676,7 +563,7 @@ func (x *UnrecognizedQueueError) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use UnrecognizedQueueError.ProtoReflect.Descriptor instead.
 func (*UnrecognizedQueueError) Descriptor() ([]byte, []int) {
-	return file_gateway_proto_rawDescGZIP(), []int{10}
+	return file_gateway_proto_rawDescGZIP(), []int{9}
 }
 
 func (x *UnrecognizedQueueError) GetError() *Error {
@@ -706,7 +593,7 @@ type RequestNotFoundError struct {
 
 func (x *RequestNotFoundError) Reset() {
 	*x = RequestNotFoundError{}
-	mi := &file_gateway_proto_msgTypes[11]
+	mi := &file_gateway_proto_msgTypes[10]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -718,7 +605,7 @@ func (x *RequestNotFoundError) String() string {
 func (*RequestNotFoundError) ProtoMessage() {}
 
 func (x *RequestNotFoundError) ProtoReflect() protoreflect.Message {
-	mi := &file_gateway_proto_msgTypes[11]
+	mi := &file_gateway_proto_msgTypes[10]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -731,7 +618,7 @@ func (x *RequestNotFoundError) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use RequestNotFoundError.ProtoReflect.Descriptor instead.
 func (*RequestNotFoundError) Descriptor() ([]byte, []int) {
-	return file_gateway_proto_rawDescGZIP(), []int{11}
+	return file_gateway_proto_rawDescGZIP(), []int{10}
 }
 
 func (x *RequestNotFoundError) GetError() *Error {
@@ -752,20 +639,18 @@ var File_gateway_proto protoreflect.FileDescriptor
 
 const file_gateway_proto_rawDesc = "" +
 	"\n" +
-	"\rgateway.proto\x12\x18uber.submitqueue.gateway\"'\n" +
+	"\rgateway.proto\x12\x18uber.submitqueue.gateway\x1a\"api/base/change/proto/change.proto\x1a0api/base/mergestrategy/proto/mergestrategy.proto\"'\n" +
 	"\vPingRequest\x12\x18\n" +
 	"\amessage\x18\x01 \x01(\tR\amessage\"\x85\x01\n" +
 	"\fPingResponse\x12\x18\n" +
 	"\amessage\x18\x01 \x01(\tR\amessage\x12!\n" +
 	"\fservice_name\x18\x02 \x01(\tR\vserviceName\x12\x1c\n" +
 	"\ttimestamp\x18\x03 \x01(\x03R\ttimestamp\x12\x1a\n" +
-	"\bhostname\x18\x04 \x01(\tR\bhostname\"\x1c\n" +
-	"\x06Change\x12\x12\n" +
-	"\x04uris\x18\x01 \x03(\tR\x04uris\"\x9d\x01\n" +
+	"\bhostname\x18\x04 \x01(\tR\bhostname\"\x94\x01\n" +
 	"\vLandRequest\x12\x14\n" +
-	"\x05queue\x18\x01 \x01(\tR\x05queue\x128\n" +
-	"\x06change\x18\x02 \x01(\v2 .uber.submitqueue.gateway.ChangeR\x06change\x12>\n" +
-	"\bstrategy\x18\x04 \x01(\x0e2\".uber.submitqueue.gateway.StrategyR\bstrategy\"\"\n" +
+	"\x05queue\x18\x01 \x01(\tR\x05queue\x120\n" +
+	"\x06change\x18\x02 \x01(\v2\x18.uber.base.change.ChangeR\x06change\x12=\n" +
+	"\bstrategy\x18\x04 \x01(\x0e2!.uber.base.mergestrategy.StrategyR\bstrategy\"\"\n" +
 	"\fLandResponse\x12\x12\n" +
 	"\x04sqid\x18\x01 \x01(\tR\x04sqid\";\n" +
 	"\rCancelRequest\x12\x12\n" +
@@ -789,13 +674,7 @@ const file_gateway_proto_rawDesc = "" +
 	"\x05queue\x18\x02 \x01(\tR\x05queue\"a\n" +
 	"\x14RequestNotFoundError\x125\n" +
 	"\x05error\x18\x01 \x01(\v2\x1f.uber.submitqueue.gateway.ErrorR\x05error\x12\x12\n" +
-	"\x04sqid\x18\x02 \x01(\tR\x04sqid*A\n" +
-	"\bStrategy\x12\v\n" +
-	"\aDEFAULT\x10\x00\x12\n" +
-	"\n" +
-	"\x06REBASE\x10\x01\x12\x11\n" +
-	"\rSQUASH_REBASE\x10\x02\x12\t\n" +
-	"\x05MERGE\x10\x032\x84\x03\n" +
+	"\x04sqid\x18\x02 \x01(\tR\x04sqid2\x84\x03\n" +
 	"\x12SubmitQueueGateway\x12W\n" +
 	"\x04Ping\x12%.uber.submitqueue.gateway.PingRequest\x1a&.uber.submitqueue.gateway.PingResponse\"\x00\x12W\n" +
 	"\x04Land\x12%.uber.submitqueue.gateway.LandRequest\x1a&.uber.submitqueue.gateway.LandResponse\"\x00\x12]\n" +
@@ -815,38 +694,37 @@ func file_gateway_proto_rawDescGZIP() []byte {
 	return file_gateway_proto_rawDescData
 }
 
-var file_gateway_proto_enumTypes = make([]protoimpl.EnumInfo, 1)
-var file_gateway_proto_msgTypes = make([]protoimpl.MessageInfo, 13)
+var file_gateway_proto_msgTypes = make([]protoimpl.MessageInfo, 12)
 var file_gateway_proto_goTypes = []any{
-	(Strategy)(0),                  // 0: uber.submitqueue.gateway.Strategy
-	(*PingRequest)(nil),            // 1: uber.submitqueue.gateway.PingRequest
-	(*PingResponse)(nil),           // 2: uber.submitqueue.gateway.PingResponse
-	(*Change)(nil),                 // 3: uber.submitqueue.gateway.Change
-	(*LandRequest)(nil),            // 4: uber.submitqueue.gateway.LandRequest
-	(*LandResponse)(nil),           // 5: uber.submitqueue.gateway.LandResponse
-	(*CancelRequest)(nil),          // 6: uber.submitqueue.gateway.CancelRequest
-	(*CancelResponse)(nil),         // 7: uber.submitqueue.gateway.CancelResponse
-	(*StatusRequest)(nil),          // 8: uber.submitqueue.gateway.StatusRequest
-	(*StatusResponse)(nil),         // 9: uber.submitqueue.gateway.StatusResponse
-	(*Error)(nil),                  // 10: uber.submitqueue.gateway.Error
-	(*UnrecognizedQueueError)(nil), // 11: uber.submitqueue.gateway.UnrecognizedQueueError
-	(*RequestNotFoundError)(nil),   // 12: uber.submitqueue.gateway.RequestNotFoundError
-	nil,                            // 13: uber.submitqueue.gateway.StatusResponse.MetadataEntry
+	(*PingRequest)(nil),            // 0: uber.submitqueue.gateway.PingRequest
+	(*PingResponse)(nil),           // 1: uber.submitqueue.gateway.PingResponse
+	(*LandRequest)(nil),            // 2: uber.submitqueue.gateway.LandRequest
+	(*LandResponse)(nil),           // 3: uber.submitqueue.gateway.LandResponse
+	(*CancelRequest)(nil),          // 4: uber.submitqueue.gateway.CancelRequest
+	(*CancelResponse)(nil),         // 5: uber.submitqueue.gateway.CancelResponse
+	(*StatusRequest)(nil),          // 6: uber.submitqueue.gateway.StatusRequest
+	(*StatusResponse)(nil),         // 7: uber.submitqueue.gateway.StatusResponse
+	(*Error)(nil),                  // 8: uber.submitqueue.gateway.Error
+	(*UnrecognizedQueueError)(nil), // 9: uber.submitqueue.gateway.UnrecognizedQueueError
+	(*RequestNotFoundError)(nil),   // 10: uber.submitqueue.gateway.RequestNotFoundError
+	nil,                            // 11: uber.submitqueue.gateway.StatusResponse.MetadataEntry
+	(*protopb.Change)(nil),         // 12: uber.base.change.Change
+	(protopb1.Strategy)(0),         // 13: uber.base.mergestrategy.Strategy
 }
 var file_gateway_proto_depIdxs = []int32{
-	3,  // 0: uber.submitqueue.gateway.LandRequest.change:type_name -> uber.submitqueue.gateway.Change
-	0,  // 1: uber.submitqueue.gateway.LandRequest.strategy:type_name -> uber.submitqueue.gateway.Strategy
-	13, // 2: uber.submitqueue.gateway.StatusResponse.metadata:type_name -> uber.submitqueue.gateway.StatusResponse.MetadataEntry
-	10, // 3: uber.submitqueue.gateway.UnrecognizedQueueError.error:type_name -> uber.submitqueue.gateway.Error
-	10, // 4: uber.submitqueue.gateway.RequestNotFoundError.error:type_name -> uber.submitqueue.gateway.Error
-	1,  // 5: uber.submitqueue.gateway.SubmitQueueGateway.Ping:input_type -> uber.submitqueue.gateway.PingRequest
-	4,  // 6: uber.submitqueue.gateway.SubmitQueueGateway.Land:input_type -> uber.submitqueue.gateway.LandRequest
-	6,  // 7: uber.submitqueue.gateway.SubmitQueueGateway.Cancel:input_type -> uber.submitqueue.gateway.CancelRequest
-	8,  // 8: uber.submitqueue.gateway.SubmitQueueGateway.Status:input_type -> uber.submitqueue.gateway.StatusRequest
-	2,  // 9: uber.submitqueue.gateway.SubmitQueueGateway.Ping:output_type -> uber.submitqueue.gateway.PingResponse
-	5,  // 10: uber.submitqueue.gateway.SubmitQueueGateway.Land:output_type -> uber.submitqueue.gateway.LandResponse
-	7,  // 11: uber.submitqueue.gateway.SubmitQueueGateway.Cancel:output_type -> uber.submitqueue.gateway.CancelResponse
-	9,  // 12: uber.submitqueue.gateway.SubmitQueueGateway.Status:output_type -> uber.submitqueue.gateway.StatusResponse
+	12, // 0: uber.submitqueue.gateway.LandRequest.change:type_name -> uber.base.change.Change
+	13, // 1: uber.submitqueue.gateway.LandRequest.strategy:type_name -> uber.base.mergestrategy.Strategy
+	11, // 2: uber.submitqueue.gateway.StatusResponse.metadata:type_name -> uber.submitqueue.gateway.StatusResponse.MetadataEntry
+	8,  // 3: uber.submitqueue.gateway.UnrecognizedQueueError.error:type_name -> uber.submitqueue.gateway.Error
+	8,  // 4: uber.submitqueue.gateway.RequestNotFoundError.error:type_name -> uber.submitqueue.gateway.Error
+	0,  // 5: uber.submitqueue.gateway.SubmitQueueGateway.Ping:input_type -> uber.submitqueue.gateway.PingRequest
+	2,  // 6: uber.submitqueue.gateway.SubmitQueueGateway.Land:input_type -> uber.submitqueue.gateway.LandRequest
+	4,  // 7: uber.submitqueue.gateway.SubmitQueueGateway.Cancel:input_type -> uber.submitqueue.gateway.CancelRequest
+	6,  // 8: uber.submitqueue.gateway.SubmitQueueGateway.Status:input_type -> uber.submitqueue.gateway.StatusRequest
+	1,  // 9: uber.submitqueue.gateway.SubmitQueueGateway.Ping:output_type -> uber.submitqueue.gateway.PingResponse
+	3,  // 10: uber.submitqueue.gateway.SubmitQueueGateway.Land:output_type -> uber.submitqueue.gateway.LandResponse
+	5,  // 11: uber.submitqueue.gateway.SubmitQueueGateway.Cancel:output_type -> uber.submitqueue.gateway.CancelResponse
+	7,  // 12: uber.submitqueue.gateway.SubmitQueueGateway.Status:output_type -> uber.submitqueue.gateway.StatusResponse
 	9,  // [9:13] is the sub-list for method output_type
 	5,  // [5:9] is the sub-list for method input_type
 	5,  // [5:5] is the sub-list for extension type_name
@@ -864,14 +742,13 @@ func file_gateway_proto_init() {
 		File: protoimpl.DescBuilder{
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: unsafe.Slice(unsafe.StringData(file_gateway_proto_rawDesc), len(file_gateway_proto_rawDesc)),
-			NumEnums:      1,
-			NumMessages:   13,
+			NumEnums:      0,
+			NumMessages:   12,
 			NumExtensions: 0,
 			NumServices:   1,
 		},
 		GoTypes:           file_gateway_proto_goTypes,
 		DependencyIndexes: file_gateway_proto_depIdxs,
-		EnumInfos:         file_gateway_proto_enumTypes,
 		MessageInfos:      file_gateway_proto_msgTypes,
 	}.Build()
 	File_gateway_proto = out.File
diff --git a/api/submitqueue/gateway/protopb/gateway.pb.yarpc.go b/api/submitqueue/gateway/protopb/gateway.pb.yarpc.go
index e1473005..70dd6aa6 100644
--- a/api/submitqueue/gateway/protopb/gateway.pb.yarpc.go
+++ b/api/submitqueue/gateway/protopb/gateway.pb.yarpc.go
@@ -376,48 +376,73 @@ var (
 var yarpcFileDescriptorClosuref1a937782ebbded5 = [][]byte{
 	// gateway.proto
 	[]byte{
-		0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xa4, 0x55, 0x51, 0x6b, 0xdb, 0x3c,
-		0x14, 0x8d, 0xe3, 0xc4, 0x4d, 0x6e, 0x92, 0x92, 0x4f, 0x94, 0x62, 0x42, 0x3f, 0x96, 0x6a, 0x6c,
-		0x0d, 0x7b, 0x70, 0x20, 0x63, 0xa3, 0xac, 0x30, 0x48, 0x3b, 0xb7, 0x7b, 0x68, 0x4b, 0x6b, 0xaf,
-		0x0c, 0x06, 0xa3, 0x28, 0x8e, 0x70, 0x4d, 0x6b, 0x3b, 0xb5, 0xe4, 0x8e, 0xec, 0x79, 0xfb, 0x19,
-		0xfb, 0x5f, 0xfb, 0x39, 0xc3, 0x92, 0xdc, 0x38, 0x30, 0xbb, 0x0f, 0x7b, 0xd3, 0xbd, 0x3a, 0xe7,
-		0xdc, 0x23, 0xe9, 0x5e, 0x1b, 0x7a, 0x3e, 0xe1, 0xf4, 0x1b, 0x59, 0x5a, 0x8b, 0x24, 0xe6, 0x31,
-		0x32, 0xd3, 0x19, 0x4d, 0x2c, 0x96, 0xce, 0xc2, 0x80, 0xdf, 0xa7, 0x34, 0xa5, 0x96, 0xda, 0xc7,
-		0x7b, 0xd0, 0xb9, 0x08, 0x22, 0xdf, 0xa1, 0xf7, 0x29, 0x65, 0x1c, 0x99, 0xb0, 0x11, 0x52, 0xc6,
-		0x88, 0x4f, 0x4d, 0x6d, 0xa8, 0x8d, 0xda, 0x4e, 0x1e, 0xe2, 0x9f, 0x1a, 0x74, 0x25, 0x92, 0x2d,
-		0xe2, 0x88, 0xd1, 0x72, 0x28, 0xda, 0x85, 0x2e, 0xa3, 0xc9, 0x43, 0xe0, 0xd1, 0xeb, 0x88, 0x84,
-		0xd4, 0xac, 0x8b, 0xed, 0x8e, 0xca, 0x9d, 0x93, 0x90, 0xa2, 0x1d, 0x68, 0xf3, 0x20, 0xa4, 0x8c,
-		0x93, 0x70, 0x61, 0xea, 0x43, 0x6d, 0xa4, 0x3b, 0xab, 0x04, 0x1a, 0x40, 0xeb, 0x26, 0x66, 0x5c,
-		0x90, 0x1b, 0x82, 0xfc, 0x18, 0xe3, 0x1d, 0x30, 0x8e, 0x6e, 0x48, 0xe4, 0x53, 0x84, 0xa0, 0x91,
-		0x26, 0x01, 0x33, 0xb5, 0xa1, 0x3e, 0x6a, 0x3b, 0x62, 0x8d, 0x7f, 0x69, 0xd0, 0x39, 0x25, 0xd1,
-		0x3c, 0x3f, 0xcf, 0x16, 0x34, 0xc5, 0x79, 0x95, 0x45, 0x19, 0xa0, 0x7d, 0x30, 0x3c, 0xa1, 0x21,
-		0xac, 0x75, 0x26, 0x43, 0xab, 0xec, 0x7e, 0x2c, 0x59, 0xcb, 0x51, 0x78, 0xf4, 0x1e, 0x5a, 0x8c,
-		0x27, 0x84, 0x53, 0x7f, 0x29, 0x9c, 0x6d, 0x4e, 0x70, 0x39, 0xd7, 0x55, 0x48, 0xe7, 0x91, 0x83,
-		0x31, 0x74, 0xa5, 0x3d, 0x75, 0x89, 0x08, 0x1a, 0xec, 0x3e, 0x98, 0x2b, 0x7b, 0x62, 0x8d, 0x0f,
-		0xa0, 0x77, 0x44, 0x22, 0x8f, 0xde, 0xe5, 0x87, 0xf8, 0x0b, 0x08, 0x6d, 0x83, 0x91, 0x50, 0xc2,
-		0xe2, 0x48, 0xdd, 0xae, 0x8a, 0x70, 0x1f, 0x36, 0x73, 0xb2, 0x2c, 0x81, 0x9f, 0x43, 0xcf, 0xe5,
-		0x84, 0xa7, 0xac, 0x42, 0x0e, 0xff, 0xd6, 0x60, 0x33, 0x47, 0x29, 0x6b, 0xdb, 0x60, 0x30, 0x91,
-		0x51, 0x40, 0x15, 0xa1, 0xff, 0x01, 0xee, 0x08, 0xe3, 0xd7, 0x34, 0x49, 0xe2, 0x44, 0x55, 0x6f,
-		0x67, 0x19, 0x3b, 0x4b, 0x20, 0x07, 0x5a, 0x21, 0xe5, 0x64, 0x4e, 0x38, 0x31, 0xf5, 0xa1, 0x3e,
-		0xea, 0x4c, 0xde, 0x56, 0xdd, 0x50, 0xb1, 0xa4, 0x75, 0xa6, 0x88, 0x76, 0xc4, 0x93, 0xa5, 0xf3,
-		0xa8, 0x33, 0x38, 0x80, 0xde, 0xda, 0x16, 0xea, 0x83, 0x7e, 0x4b, 0x97, 0xca, 0x58, 0xb6, 0xcc,
-		0x1e, 0xfa, 0x81, 0xdc, 0xa5, 0x79, 0xb3, 0xc9, 0xe0, 0x5d, 0x7d, 0x5f, 0xc3, 0xbb, 0xd0, 0x94,
-		0xce, 0xca, 0x7b, 0x9b, 0xc2, 0xf6, 0x55, 0x94, 0x50, 0x2f, 0xf6, 0xa3, 0xe0, 0x3b, 0x9d, 0x5f,
-		0x66, 0x1e, 0x25, 0xe7, 0x0d, 0x34, 0xe5, 0x39, 0x35, 0xd1, 0x28, 0xcf, 0xca, 0x8f, 0x22, 0xf0,
-		0x8e, 0x44, 0xaf, 0xda, 0xae, 0x5e, 0x68, 0x3b, 0x4c, 0x60, 0x4b, 0xbd, 0xc1, 0x79, 0xcc, 0x8f,
-		0xe3, 0x34, 0x9a, 0xff, 0x53, 0x91, 0xfc, 0x1d, 0xeb, 0xab, 0x77, 0x7c, 0x35, 0x85, 0x56, 0xde,
-		0x75, 0xa8, 0x03, 0x1b, 0x1f, 0xec, 0xe3, 0xe9, 0xd5, 0xe9, 0xa7, 0x7e, 0x0d, 0x01, 0x18, 0x8e,
-		0x7d, 0x38, 0x75, 0xed, 0xbe, 0x86, 0xfe, 0x83, 0x9e, 0x7b, 0x79, 0x35, 0x75, 0x3f, 0x5e, 0xab,
-		0x54, 0x1d, 0xb5, 0xa1, 0x79, 0x66, 0x3b, 0x27, 0x76, 0x5f, 0x9f, 0xfc, 0xd0, 0x01, 0xb9, 0xa2,
-		0xb6, 0xb8, 0x87, 0x13, 0x59, 0x1a, 0x7d, 0x86, 0x46, 0x36, 0xfe, 0xe8, 0x45, 0xb9, 0xbb, 0xc2,
-		0x87, 0x64, 0xf0, 0xf2, 0x29, 0x98, 0xea, 0xce, 0x5a, 0x26, 0x9c, 0x8d, 0x44, 0x95, 0x70, 0x61,
-		0xa2, 0xab, 0x84, 0x8b, 0x93, 0x85, 0x6b, 0xe8, 0x2b, 0x18, 0x72, 0x14, 0xd0, 0x5e, 0xc5, 0x7c,
-		0x17, 0x27, 0x6d, 0x30, 0x7a, 0x1a, 0x58, 0x94, 0x97, 0xed, 0x5b, 0x25, 0xbf, 0x36, 0x79, 0x55,
-		0xf2, 0xeb, 0x93, 0x80, 0x6b, 0x87, 0xb7, 0xb0, 0xe3, 0xc5, 0x61, 0x29, 0xe1, 0xb0, 0xab, 0x1e,
-		0xe6, 0x22, 0xfb, 0xc0, 0x5f, 0x68, 0x5f, 0x0e, 0xfc, 0x80, 0xdf, 0xa4, 0x33, 0xcb, 0x8b, 0xc3,
-		0x71, 0x46, 0x1a, 0x17, 0x48, 0x63, 0xb2, 0x08, 0xd6, 0x62, 0x25, 0x32, 0x16, 0x7f, 0x87, 0xc5,
-		0x6c, 0x66, 0x88, 0xc5, 0xeb, 0x3f, 0x01, 0x00, 0x00, 0xff, 0xff, 0x48, 0x81, 0xac, 0xa4, 0x37,
-		0x06, 0x00, 0x00,
+		0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xa4, 0x54, 0x5f, 0x6b, 0xd4, 0x40,
+		0x10, 0x6f, 0x2e, 0xed, 0xd9, 0xce, 0xdd, 0x95, 0xb2, 0x94, 0x12, 0x42, 0xc5, 0x76, 0x45, 0x7b,
+		0x4f, 0x49, 0x39, 0x51, 0xc4, 0xe2, 0x4b, 0x4b, 0xf5, 0x45, 0x4b, 0x4d, 0x11, 0x41, 0x90, 0xb2,
+		0xc9, 0x0d, 0xb9, 0xd0, 0x4b, 0x72, 0x97, 0xdd, 0x54, 0xce, 0x67, 0xfd, 0x06, 0x7e, 0x38, 0x3f,
+		0x8e, 0xec, 0x9f, 0xdc, 0x25, 0x60, 0xae, 0x0f, 0x3e, 0x65, 0x67, 0xf2, 0xfb, 0xcd, 0xcc, 0xce,
+		0xfc, 0x66, 0x61, 0x10, 0x33, 0x81, 0xdf, 0xd9, 0xc2, 0x9b, 0x15, 0xb9, 0xc8, 0x89, 0x53, 0x86,
+		0x58, 0x78, 0xbc, 0x0c, 0xd3, 0x44, 0xcc, 0x4b, 0x2c, 0xd1, 0x33, 0xff, 0x5d, 0xca, 0x66, 0x89,
+		0x1f, 0x32, 0x8e, 0x7e, 0x34, 0x61, 0x59, 0x8c, 0xbe, 0x22, 0x18, 0x43, 0xb3, 0xdd, 0xd3, 0x25,
+		0x26, 0xc5, 0x22, 0x46, 0x2e, 0x0a, 0x26, 0x30, 0x5e, 0x18, 0x68, 0xc3, 0xa7, 0x19, 0xf4, 0x04,
+		0x7a, 0xd7, 0x49, 0x16, 0x07, 0x38, 0x2f, 0x91, 0x0b, 0xe2, 0xc0, 0xa3, 0x14, 0x39, 0x67, 0x31,
+		0x3a, 0xd6, 0x91, 0x35, 0xdc, 0x09, 0x2a, 0x93, 0xfe, 0xb2, 0xa0, 0xaf, 0x91, 0x7c, 0x96, 0x67,
+		0x1c, 0xdb, 0xa1, 0xe4, 0x18, 0xfa, 0x1c, 0x8b, 0xfb, 0x24, 0xc2, 0xdb, 0x8c, 0xa5, 0xe8, 0x74,
+		0xd4, 0xef, 0x9e, 0xf1, 0x5d, 0xb1, 0x14, 0xc9, 0x21, 0xec, 0x88, 0x24, 0x45, 0x2e, 0x58, 0x3a,
+		0x73, 0xec, 0x23, 0x6b, 0x68, 0x07, 0x2b, 0x07, 0x71, 0x61, 0x7b, 0x92, 0x73, 0xa1, 0xc8, 0x9b,
+		0x8a, 0xbc, 0xb4, 0xe9, 0x6f, 0x0b, 0x7a, 0x1f, 0x58, 0x36, 0xae, 0x2a, 0xde, 0x87, 0x2d, 0xd5,
+		0x27, 0x53, 0x84, 0x36, 0xc8, 0x29, 0x74, 0x75, 0x63, 0x54, 0xf2, 0xde, 0xc8, 0xf1, 0x54, 0x5f,
+		0x65, 0x6b, 0x3c, 0xd3, 0xb1, 0x0b, 0xf5, 0x09, 0x0c, 0x8e, 0xbc, 0x85, 0xed, 0xaa, 0x35, 0x2a,
+		0xe7, 0xee, 0xe8, 0xb8, 0xc6, 0x69, 0xb6, 0xee, 0xc6, 0x1c, 0x82, 0x25, 0x85, 0x52, 0xe8, 0xeb,
+		0xaa, 0x4c, 0x77, 0x08, 0x6c, 0xf2, 0x79, 0x32, 0x36, 0x55, 0xa9, 0x33, 0x3d, 0x83, 0xc1, 0x05,
+		0xcb, 0x22, 0x9c, 0x56, 0xb5, 0xff, 0x03, 0x44, 0x0e, 0xa0, 0x5b, 0x20, 0xe3, 0x79, 0x66, 0xda,
+		0x66, 0x2c, 0xba, 0x07, 0xbb, 0x15, 0x59, 0xa7, 0xa0, 0x4f, 0x61, 0x70, 0x23, 0x98, 0x28, 0xf9,
+		0x9a, 0x70, 0xf4, 0x8f, 0x05, 0xbb, 0x15, 0xca, 0x94, 0x76, 0x00, 0x5d, 0xae, 0x3c, 0x06, 0x68,
+		0x2c, 0xf2, 0x18, 0x60, 0xca, 0xb8, 0xb8, 0xc5, 0xa2, 0xc8, 0x0b, 0x93, 0x7d, 0x47, 0x7a, 0x2e,
+		0xa5, 0x83, 0x04, 0xb0, 0x9d, 0xa2, 0x60, 0x63, 0x26, 0x98, 0x63, 0x1f, 0xd9, 0xc3, 0xde, 0xe8,
+		0x95, 0xd7, 0x26, 0x56, 0xaf, 0x99, 0xd2, 0xfb, 0x68, 0x88, 0x97, 0x99, 0x28, 0x16, 0xc1, 0x32,
+		0x8e, 0x7b, 0x06, 0x83, 0xc6, 0x2f, 0xb2, 0x07, 0xf6, 0x1d, 0x2e, 0x4c, 0x61, 0xf2, 0x28, 0xe7,
+		0x7b, 0xcf, 0xa6, 0x65, 0xa5, 0x22, 0x6d, 0xbc, 0xe9, 0xbc, 0xb6, 0xe8, 0x31, 0x6c, 0xe9, 0xca,
+		0xda, 0x45, 0x8b, 0x70, 0xf0, 0x39, 0x2b, 0x30, 0xca, 0xe3, 0x2c, 0xf9, 0x81, 0xe3, 0x4f, 0xb2,
+		0x46, 0xcd, 0x79, 0x09, 0x5b, 0xfa, 0x9e, 0x96, 0xd2, 0xc7, 0x93, 0xf6, 0xab, 0x28, 0x7c, 0xa0,
+		0xd1, 0x2b, 0xb5, 0x75, 0x6a, 0x6a, 0xa3, 0x0c, 0xf6, 0xcd, 0x0c, 0xae, 0x72, 0xf1, 0x2e, 0x2f,
+		0xb3, 0xf1, 0x7f, 0x25, 0xa9, 0xe6, 0xd8, 0x59, 0xcd, 0x71, 0xf4, 0xd3, 0x06, 0x72, 0xa3, 0x88,
+		0xea, 0x12, 0xef, 0x35, 0x8f, 0x7c, 0x81, 0x4d, 0xb9, 0x94, 0xe4, 0x59, 0x7b, 0xe8, 0xda, 0x7a,
+		0xbb, 0xcf, 0x1f, 0x82, 0x19, 0x69, 0x6d, 0xc8, 0xc0, 0x52, 0xcf, 0xeb, 0x02, 0xd7, 0xb6, 0x70,
+		0x5d, 0xe0, 0xfa, 0x5a, 0xd0, 0x0d, 0xf2, 0x0d, 0xba, 0x5a, 0xc7, 0xe4, 0xa4, 0x9d, 0xd3, 0x58,
+		0x13, 0x77, 0xf8, 0x30, 0xb0, 0x1e, 0x5e, 0x6b, 0x6f, 0x5d, 0xf8, 0xc6, 0xda, 0xac, 0x0b, 0xdf,
+		0x94, 0x31, 0xdd, 0x38, 0xbf, 0x83, 0xc3, 0x28, 0x4f, 0x5b, 0x09, 0xe7, 0x7d, 0x33, 0x98, 0x6b,
+		0xf9, 0xb8, 0x5e, 0x5b, 0x5f, 0xcf, 0xe2, 0x44, 0x4c, 0xca, 0xd0, 0x8b, 0xf2, 0xd4, 0x97, 0x24,
+		0xbf, 0x46, 0xf2, 0xe5, 0x63, 0x5d, 0xb7, 0x4d, 0x10, 0xfd, 0x5a, 0xcf, 0xc2, 0xb0, 0xab, 0x0e,
+		0x2f, 0xfe, 0x06, 0x00, 0x00, 0xff, 0xff, 0x01, 0x08, 0x76, 0xa7, 0x23, 0x06, 0x00, 0x00,
+	},
+	// api/base/change/proto/change.proto
+	[]byte{
+		0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xe2, 0x52, 0x4a, 0x2c, 0xc8, 0xd4,
+		0x4f, 0x4a, 0x2c, 0x4e, 0xd5, 0x4f, 0xce, 0x48, 0xcc, 0x4b, 0x4f, 0xd5, 0x2f, 0x28, 0xca, 0x2f,
+		0xc9, 0x87, 0x72, 0xf4, 0xc0, 0x1c, 0x21, 0x81, 0xd2, 0xa4, 0xd4, 0x22, 0x3d, 0x90, 0x22, 0x3d,
+		0x88, 0xb8, 0x92, 0x0c, 0x17, 0x9b, 0x33, 0x98, 0x25, 0x24, 0xc4, 0xc5, 0x52, 0x5a, 0x94, 0x59,
+		0x2c, 0xc1, 0xa8, 0xc0, 0xac, 0xc1, 0x19, 0x04, 0x66, 0x3b, 0xa5, 0x71, 0x29, 0x24, 0xe7, 0xe7,
+		0xea, 0x81, 0x75, 0x15, 0x97, 0x26, 0xe5, 0x66, 0x96, 0x14, 0x96, 0xa6, 0x96, 0xa6, 0x22, 0x9b,
+		0xe0, 0xc4, 0x0d, 0xd1, 0x1f, 0x00, 0xb2, 0x20, 0x80, 0x31, 0xca, 0x38, 0x3d, 0xb3, 0x24, 0xa3,
+		0x34, 0x49, 0x2f, 0x39, 0x3f, 0x57, 0x1f, 0xa4, 0x4f, 0x1f, 0x49, 0x9f, 0x3e, 0x56, 0x27, 0x16,
+		0x24, 0x25, 0xb1, 0x81, 0x19, 0xc6, 0x80, 0x00, 0x00, 0x00, 0xff, 0xff, 0xbf, 0x91, 0x62, 0xef,
+		0xc4, 0x00, 0x00, 0x00,
+	},
+	// api/base/mergestrategy/proto/mergestrategy.proto
+	[]byte{
+		0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xe2, 0x32, 0x48, 0x2c, 0xc8, 0xd4,
+		0x4f, 0x4a, 0x2c, 0x4e, 0xd5, 0xcf, 0x4d, 0x2d, 0x4a, 0x4f, 0x2d, 0x2e, 0x29, 0x4a, 0x2c, 0x49,
+		0x4d, 0xaf, 0xd4, 0x2f, 0x28, 0xca, 0x2f, 0xc9, 0x47, 0x15, 0xd3, 0x03, 0x8b, 0x09, 0x89, 0x97,
+		0x26, 0xa5, 0x16, 0xe9, 0x81, 0xb4, 0xe8, 0xa1, 0x48, 0x6b, 0x39, 0x72, 0x71, 0x04, 0x43, 0xd9,
+		0x42, 0xdc, 0x5c, 0xec, 0x2e, 0xae, 0x6e, 0x8e, 0xa1, 0x3e, 0x21, 0x02, 0x0c, 0x42, 0x5c, 0x5c,
+		0x6c, 0x41, 0xae, 0x4e, 0x8e, 0xc1, 0xae, 0x02, 0x8c, 0x42, 0x82, 0x5c, 0xbc, 0xc1, 0x81, 0xa1,
+		0x8e, 0xc1, 0x1e, 0xf1, 0x50, 0x21, 0x26, 0x21, 0x4e, 0x2e, 0x56, 0x5f, 0xd7, 0x20, 0x77, 0x57,
+		0x01, 0x66, 0xa7, 0x6a, 0x2e, 0xf5, 0xe4, 0xfc, 0x5c, 0x3d, 0xb0, 0x0d, 0xc5, 0xa5, 0x49, 0xb9,
+		0x99, 0x25, 0x85, 0xa5, 0xa9, 0xa5, 0xa9, 0x58, 0x6c, 0x73, 0x12, 0xf2, 0x05, 0x71, 0x61, 0x16,
+		0x06, 0x80, 0x9c, 0x16, 0xc0, 0x18, 0x65, 0x95, 0x9e, 0x59, 0x92, 0x51, 0x9a, 0xa4, 0x97, 0x9c,
+		0x9f, 0xab, 0x0f, 0x32, 0x45, 0x1f, 0xc9, 0x14, 0x7d, 0x7c, 0x5e, 0x2d, 0x48, 0x4a, 0x62, 0x03,
+		0x33, 0x8c, 0x01, 0x01, 0x00, 0x00, 0xff, 0xff, 0xc6, 0xe5, 0x5f, 0xa5, 0x13, 0x01, 0x00, 0x00,
 	},
 }
 
diff --git a/submitqueue/gateway/controller/BUILD.bazel b/submitqueue/gateway/controller/BUILD.bazel
index 69d08fb9..a2dbdbde 100644
--- a/submitqueue/gateway/controller/BUILD.bazel
+++ b/submitqueue/gateway/controller/BUILD.bazel
@@ -11,6 +11,7 @@ go_library(
     importpath = "github.com/uber/submitqueue/submitqueue/gateway/controller",
     visibility = ["//visibility:public"],
     deps = [
+        "//api/base/mergestrategy/protopb",
         "//api/submitqueue/gateway/protopb",
         "//platform/base/change",
         "//platform/base/mergestrategy",
@@ -39,6 +40,8 @@ go_test(
     ],
     embed = [":controller"],
     deps = [
+        "//api/base/change/protopb",
+        "//api/base/mergestrategy/protopb",
         "//api/submitqueue/gateway/protopb",
         "//platform/base/mergestrategy",
         "//platform/base/messagequeue",
diff --git a/submitqueue/gateway/controller/land.go b/submitqueue/gateway/controller/land.go
index b80218c1..6e15c72f 100644
--- a/submitqueue/gateway/controller/land.go
+++ b/submitqueue/gateway/controller/land.go
@@ -20,6 +20,7 @@ import (
 	"fmt"
 
 	"github.com/uber-go/tally"
+	mergestrategypb "github.com/uber/submitqueue/api/base/mergestrategy/protopb"
 	pb "github.com/uber/submitqueue/api/submitqueue/gateway/protopb"
 	"github.com/uber/submitqueue/platform/base/change"
 	"github.com/uber/submitqueue/platform/base/mergestrategy"
@@ -197,16 +198,16 @@ func (c *LandController) publishToQueue(ctx context.Context, landRequest entity.
 }
 
 // resolveMergeStrategy maps a proto Strategy enum to the shared mergestrategy.MergeStrategy.
-func resolveMergeStrategy(s pb.Strategy) (mergestrategy.MergeStrategy, error) {
+func resolveMergeStrategy(s mergestrategypb.Strategy) (mergestrategy.MergeStrategy, error) {
 	switch s {
-	case pb.Strategy_DEFAULT:
+	case mergestrategypb.Strategy_DEFAULT:
 		// TODO: resolve default strategy based on queue configuration
 		return mergestrategy.MergeStrategyRebase, nil
-	case pb.Strategy_REBASE:
+	case mergestrategypb.Strategy_REBASE:
 		return mergestrategy.MergeStrategyRebase, nil
-	case pb.Strategy_SQUASH_REBASE:
+	case mergestrategypb.Strategy_SQUASH_REBASE:
 		return mergestrategy.MergeStrategySquashRebase, nil
-	case pb.Strategy_MERGE:
+	case mergestrategypb.Strategy_MERGE:
 		return mergestrategy.MergeStrategyMerge, nil
 	default:
 		return mergestrategy.MergeStrategyUnknown, fmt.Errorf("unknown land strategy in proto message: %v", s)
diff --git a/submitqueue/gateway/controller/land_test.go b/submitqueue/gateway/controller/land_test.go
index 058b5eec..01252d61 100644
--- a/submitqueue/gateway/controller/land_test.go
+++ b/submitqueue/gateway/controller/land_test.go
@@ -22,6 +22,8 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"github.com/uber-go/tally"
+	changepb "github.com/uber/submitqueue/api/base/change/protopb"
+	mergestrategypb "github.com/uber/submitqueue/api/base/mergestrategy/protopb"
 	pb "github.com/uber/submitqueue/api/submitqueue/gateway/protopb"
 	"github.com/uber/submitqueue/platform/base/mergestrategy"
 	entityqueue "github.com/uber/submitqueue/platform/base/messagequeue"
@@ -100,7 +102,7 @@ func TestLand_ReturnsSqid(t *testing.T) {
 
 	req := &pb.LandRequest{
 		Queue:  "test-queue",
-		Change: &pb.Change{Uris: []string{"github://uber/test-repo/pull/123/c3a4d5e6f7890123456789abcdef0123456789ab"}},
+		Change: &changepb.Change{Uris: []string{"github://uber/test-repo/pull/123/c3a4d5e6f7890123456789abcdef0123456789ab"}},
 	}
 	resp, err := controller.Land(ctx, req)
 
@@ -118,7 +120,7 @@ func TestLand_ReturnsErrorOnCounterFailure(t *testing.T) {
 
 	req := &pb.LandRequest{
 		Queue:  "test-queue",
-		Change: &pb.Change{Uris: []string{"github://uber/test-repo/pull/123/c3a4d5e6f7890123456789abcdef0123456789ab"}},
+		Change: &changepb.Change{Uris: []string{"github://uber/test-repo/pull/123/c3a4d5e6f7890123456789abcdef0123456789ab"}},
 	}
 	_, err := controller.Land(ctx, req)
 
@@ -142,7 +144,7 @@ func TestLand_CounterDomainIncludesQueue(t *testing.T) {
 
 	req := &pb.LandRequest{
 		Queue:  "my-queue",
-		Change: &pb.Change{Uris: []string{"github://uber/test-repo/pull/123/c3a4d5e6f7890123456789abcdef0123456789ab"}},
+		Change: &changepb.Change{Uris: []string{"github://uber/test-repo/pull/123/c3a4d5e6f7890123456789abcdef0123456789ab"}},
 	}
 	_, err := controller.Land(ctx, req)
 
@@ -159,7 +161,7 @@ func TestLand_ReturnsErrorOnEmptyQueue(t *testing.T) {
 
 	req := &pb.LandRequest{
 		Queue:  "",
-		Change: &pb.Change{Uris: []string{"github://uber/test-repo/pull/123/c3a4d5e6f7890123456789abcdef0123456789ab"}},
+		Change: &changepb.Change{Uris: []string{"github://uber/test-repo/pull/123/c3a4d5e6f7890123456789abcdef0123456789ab"}},
 	}
 	_, err := controller.Land(ctx, req)
 
@@ -176,7 +178,7 @@ func TestLand_ReturnsErrorOnEmptyChangeUri(t *testing.T) {
 
 	req := &pb.LandRequest{
 		Queue:  "test-queue",
-		Change: &pb.Change{Uris: []string{}},
+		Change: &changepb.Change{Uris: []string{}},
 	}
 	_, err := controller.Land(ctx, req)
 
@@ -213,7 +215,7 @@ func TestLand_ReturnsUnrecognizedQueueWhenStoreReportsNotFound(t *testing.T) {
 
 	req := &pb.LandRequest{
 		Queue:  "missing-queue",
-		Change: &pb.Change{Uris: []string{"github://uber/test-repo/pull/123/c3a4d5e6f7890123456789abcdef0123456789ab"}},
+		Change: &changepb.Change{Uris: []string{"github://uber/test-repo/pull/123/c3a4d5e6f7890123456789abcdef0123456789ab"}},
 	}
 	_, err := controller.Land(ctx, req)
 
@@ -239,7 +241,7 @@ func TestLand_PropagatesQueueConfigStoreError(t *testing.T) {
 
 	req := &pb.LandRequest{
 		Queue:  "test-queue",
-		Change: &pb.Change{Uris: []string{"github://uber/test-repo/pull/123/c3a4d5e6f7890123456789abcdef0123456789ab"}},
+		Change: &changepb.Change{Uris: []string{"github://uber/test-repo/pull/123/c3a4d5e6f7890123456789abcdef0123456789ab"}},
 	}
 	_, err := controller.Land(ctx, req)
 
@@ -271,8 +273,8 @@ func TestLand_PublishesToQueue(t *testing.T) {
 
 	req := &pb.LandRequest{
 		Queue:    "test-queue",
-		Change:   &pb.Change{Uris: []string{"github://uber/backend/pull/456/fedcba9876543210fedcba9876543210fedcba98"}},
-		Strategy: pb.Strategy_REBASE,
+		Change:   &changepb.Change{Uris: []string{"github://uber/backend/pull/456/fedcba9876543210fedcba9876543210fedcba98"}},
+		Strategy: mergestrategypb.Strategy_REBASE,
 	}
 	resp, err := controller.Land(ctx, req)
 
@@ -307,7 +309,7 @@ func TestLand_ContinuesWhenPublishFails(t *testing.T) {
 
 	req := &pb.LandRequest{
 		Queue:  "test-queue",
-		Change: &pb.Change{Uris: []string{"github://uber/service/pull/1/c3a4d5e6f7890123456789abcdef0123456789ab"}},
+		Change: &changepb.Change{Uris: []string{"github://uber/service/pull/1/c3a4d5e6f7890123456789abcdef0123456789ab"}},
 	}
 	_, err := controller.Land(ctx, req)
 
diff --git a/test/e2e/submitqueue/BUILD.bazel b/test/e2e/submitqueue/BUILD.bazel
index 5f964ae7..94d1d5da 100644
--- a/test/e2e/submitqueue/BUILD.bazel
+++ b/test/e2e/submitqueue/BUILD.bazel
@@ -17,6 +17,8 @@ go_test(
         "integration",
     ],
     deps = [
+        "//api/base/change/protopb",
+        "//api/base/mergestrategy/protopb",
         "//api/submitqueue/gateway/protopb",
         "//api/submitqueue/orchestrator/protopb",
         "//submitqueue/entity",
diff --git a/test/e2e/submitqueue/suite_test.go b/test/e2e/submitqueue/suite_test.go
index 59553c37..e124452a 100644
--- a/test/e2e/submitqueue/suite_test.go
+++ b/test/e2e/submitqueue/suite_test.go
@@ -32,6 +32,8 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"github.com/stretchr/testify/suite"
+	changepb "github.com/uber/submitqueue/api/base/change/protopb"
+	mergestrategypb "github.com/uber/submitqueue/api/base/mergestrategy/protopb"
 	gatewaypb "github.com/uber/submitqueue/api/submitqueue/gateway/protopb"
 	orchestratorpb "github.com/uber/submitqueue/api/submitqueue/orchestrator/protopb"
 	"github.com/uber/submitqueue/submitqueue/entity"
@@ -170,8 +172,8 @@ func (s *E2EIntegrationSuite) TestPingOrchestrator() {
 func (s *E2EIntegrationSuite) TestLandRequest_SinglePR() {
 	req := &gatewaypb.LandRequest{
 		Queue:    "e2e-test-queue",
-		Change:   &gatewaypb.Change{Uris: []string{"github://uber/e2e-service/pull/123/abcdef0123456789abcdef0123456789abcdef01"}},
-		Strategy: gatewaypb.Strategy_REBASE,
+		Change:   &changepb.Change{Uris: []string{"github://uber/e2e-service/pull/123/abcdef0123456789abcdef0123456789abcdef01"}},
+		Strategy: mergestrategypb.Strategy_REBASE,
 	}
 
 	s.log.Logf("Sending Land request (single PR) for queue=%s", req.Queue)
@@ -197,8 +199,8 @@ func (s *E2EIntegrationSuite) TestLandRequest_PersistsStartedLogViaGatewayConsum
 
 	landResp, err := s.gatewayClient.Land(s.ctx, &gatewaypb.LandRequest{
 		Queue:    "e2e-test-queue",
-		Change:   &gatewaypb.Change{Uris: []string{"github://uber/e2e-startlog/pull/4242/abcdef0123456789abcdef0123456789abcdef01"}},
-		Strategy: gatewaypb.Strategy_REBASE,
+		Change:   &changepb.Change{Uris: []string{"github://uber/e2e-startlog/pull/4242/abcdef0123456789abcdef0123456789abcdef01"}},
+		Strategy: mergestrategypb.Strategy_REBASE,
 	})
 	require.NoError(t, err, "Land request failed")
 	require.NotEmpty(t, landResp.Sqid, "SQID should not be empty")
@@ -245,8 +247,8 @@ func (s *E2EIntegrationSuite) TestCancelRequest_BeforeBatch() {
 
 	landReq := &gatewaypb.LandRequest{
 		Queue:    "e2e-cancel-queue",
-		Change:   &gatewaypb.Change{Uris: []string{"github://uber/e2e-nonexistent/pull/9999/deadbeef"}},
-		Strategy: gatewaypb.Strategy_REBASE,
+		Change:   &changepb.Change{Uris: []string{"github://uber/e2e-nonexistent/pull/9999/deadbeef"}},
+		Strategy: mergestrategypb.Strategy_REBASE,
 	}
 	landResp, err := s.gatewayClient.Land(s.ctx, landReq)
 	require.NoError(t, err, "Land failed")
diff --git a/test/integration/submitqueue/gateway/BUILD.bazel b/test/integration/submitqueue/gateway/BUILD.bazel
index d90f1fae..25aebc41 100644
--- a/test/integration/submitqueue/gateway/BUILD.bazel
+++ b/test/integration/submitqueue/gateway/BUILD.bazel
@@ -16,6 +16,8 @@ go_test(
         "integration",
     ],
     deps = [
+        "//api/base/change/protopb",
+        "//api/base/mergestrategy/protopb",
         "//api/submitqueue/gateway/protopb",
         "//platform/consumer",
         "//platform/extension/messagequeue/mysql",
diff --git a/test/integration/submitqueue/gateway/suite_test.go b/test/integration/submitqueue/gateway/suite_test.go
index 5415ad1f..eab37662 100644
--- a/test/integration/submitqueue/gateway/suite_test.go
+++ b/test/integration/submitqueue/gateway/suite_test.go
@@ -36,6 +36,8 @@ import (
 	"github.com/stretchr/testify/require"
 	"github.com/stretchr/testify/suite"
 	"github.com/uber-go/tally"
+	changepb "github.com/uber/submitqueue/api/base/change/protopb"
+	mergestrategypb "github.com/uber/submitqueue/api/base/mergestrategy/protopb"
 	pb "github.com/uber/submitqueue/api/submitqueue/gateway/protopb"
 	"github.com/uber/submitqueue/platform/consumer"
 	queueMySQL "github.com/uber/submitqueue/platform/extension/messagequeue/mysql"
@@ -144,8 +146,8 @@ func (s *GatewayIntegrationSuite) TestLandAPI() {
 
 	req := &pb.LandRequest{
 		Queue:    "test-queue",
-		Change:   &pb.Change{Uris: []string{"github://uber/integration-test/pull/123/abcdef0123456789abcdef0123456789abcdef01"}},
-		Strategy: pb.Strategy_REBASE,
+		Change:   &changepb.Change{Uris: []string{"github://uber/integration-test/pull/123/abcdef0123456789abcdef0123456789abcdef01"}},
+		Strategy: mergestrategypb.Strategy_REBASE,
 	}
 
 	s.log.Logf("Sending Land request for queue=%s", req.Queue)
diff --git a/tool/proto/BUILD.bazel b/tool/proto/BUILD.bazel
index 03e3957c..b230014e 100644
--- a/tool/proto/BUILD.bazel
+++ b/tool/proto/BUILD.bazel
@@ -1,8 +1,35 @@
 load("//tool/proto:proto_codegen.bzl", "go_proto_generated_files")
 
+# Shared api/base contracts. Message-only (no RPC service), so the gRPC/YARPC
+# generators are disabled. Other packages import these instead of redefining them.
+go_proto_generated_files(
+    name = "api_base_change",
+    srcs = ["//api/base/change/proto:change.proto"],
+    gen_services = False,
+    out_dir = "api_base_change",
+)
+
+go_proto_generated_files(
+    name = "api_base_mergestrategy",
+    srcs = ["//api/base/mergestrategy/proto:mergestrategy.proto"],
+    gen_services = False,
+    out_dir = "api_base_mergestrategy",
+)
+
+go_proto_generated_files(
+    name = "api_base_messagequeue",
+    srcs = ["//api/base/messagequeue/proto:messagequeue.proto"],
+    gen_services = False,
+    out_dir = "api_base_messagequeue",
+)
+
 go_proto_generated_files(
     name = "api_submitqueue_gateway",
     srcs = ["//api/submitqueue/gateway/proto:gateway.proto"],
+    imports = [
+        "//api/base/change/proto:change.proto",
+        "//api/base/mergestrategy/proto:mergestrategy.proto",
+    ],
     out_dir = "api_submitqueue_gateway",
 )
 
@@ -27,6 +54,9 @@ go_proto_generated_files(
 filegroup(
     name = "generated",
     srcs = [
+        ":api_base_change",
+        ":api_base_mergestrategy",
+        ":api_base_messagequeue",
         ":api_stovepipe_gateway",
         ":api_stovepipe_orchestrator",
         ":api_submitqueue_gateway",
diff --git a/tool/proto/proto_codegen.bzl b/tool/proto/proto_codegen.bzl
index 56e71425..89956c53 100644
--- a/tool/proto/proto_codegen.bzl
+++ b/tool/proto/proto_codegen.bzl
@@ -18,36 +18,55 @@ def _go_proto_generated_files_impl(ctx):
         ctx.executable._protoc_gen_yarpc_go,
     ]
 
+    # Imported .proto files (e.g. the shared api/base contracts) must be present
+    # in the sandbox and resolvable on the import path. They are generated by
+    # their own target, so they are NOT passed as sources to compile here — they
+    # only provide type/go_package information for the importing source.
+    import_files = ctx.files.imports
+
     all_outputs = []
 
     # Generate independently per source so a package can hold multiple .proto
     # files (e.g. an RPC service contract alongside messagequeue contracts).
     for src in ctx.files.srcs:
         base = _strip_proto_suffix(src.basename)
-        outputs = [
-            ctx.actions.declare_file("{}/{}.pb.go".format(out_dir, base)),
-            ctx.actions.declare_file("{}/{}.pb.yarpc.go".format(out_dir, base)),
-            ctx.actions.declare_file("{}/{}_grpc.pb.go".format(out_dir, base)),
-        ]
+        outputs = [ctx.actions.declare_file("{}/{}.pb.go".format(out_dir, base))]
+
+        # protoc-gen-go-grpc and protoc-gen-yarpc-go-v2 only emit a file when the
+        # source declares at least one service. Message-only contracts (e.g. the
+        # shared api/base types) set gen_services = False so Bazel does not expect
+        # outputs that protoc never produces.
+        if ctx.attr.gen_services:
+            outputs.append(ctx.actions.declare_file("{}/{}.pb.yarpc.go".format(out_dir, base)))
+            outputs.append(ctx.actions.declare_file("{}/{}_grpc.pb.go".format(out_dir, base)))
         all_outputs.extend(outputs)
 
         args = ctx.actions.args()
         for opt in proto_toolchain.protoc_opts:
             args.add(opt)
         args.add("--plugin=protoc-gen-go={}".format(ctx.executable._protoc_gen_go.path))
-        args.add("--plugin=protoc-gen-go-grpc={}".format(ctx.executable._protoc_gen_go_grpc.path))
-        args.add("--plugin=protoc-gen-yarpc-go-v2={}".format(ctx.executable._protoc_gen_yarpc_go.path))
         args.add("--go_out={}".format(outputs[0].dirname))
         args.add("--go_opt=paths=source_relative")
-        args.add("--go-grpc_out={}".format(outputs[0].dirname))
-        args.add("--go-grpc_opt=paths=source_relative")
-        args.add("--yarpc-go-v2_out={}".format(outputs[0].dirname))
-        args.add("--yarpc-go-v2_opt=paths=source_relative")
+        if ctx.attr.gen_services:
+            args.add("--plugin=protoc-gen-go-grpc={}".format(ctx.executable._protoc_gen_go_grpc.path))
+            args.add("--plugin=protoc-gen-yarpc-go-v2={}".format(ctx.executable._protoc_gen_yarpc_go.path))
+            args.add("--go-grpc_out={}".format(outputs[0].dirname))
+            args.add("--go-grpc_opt=paths=source_relative")
+            args.add("--yarpc-go-v2_out={}".format(outputs[0].dirname))
+            args.add("--yarpc-go-v2_opt=paths=source_relative")
+
+        # The source's own directory is listed first so its generated files stay
+        # flat in out_dir (source_relative output collapses to the basename). The
+        # exec root is added only when there are imports, so cross-package imports
+        # written as repo-relative paths (e.g. "api/base/change/proto/change.proto")
+        # resolve without nesting the primary source's output.
         args.add("--proto_path={}".format(src.dirname))
+        if import_files:
+            args.add("--proto_path=.")
         args.add(src.path)
 
         ctx.actions.run_shell(
-            inputs = [src],
+            inputs = [src] + import_files,
             outputs = outputs,
             tools = tools,
             command = "mkdir -p {out_dir} && {protoc} \"$@\"".format(
@@ -69,6 +88,15 @@ go_proto_generated_files = rule(
             mandatory = True,
         ),
         "out_dir": attr.string(mandatory = True),
+        "imports": attr.label_list(
+            allow_files = [".proto"],
+            default = [],
+            doc = "Imported .proto files made available on the import path but not compiled here.",
+        ),
+        "gen_services": attr.bool(
+            default = True,
+            doc = "Whether to run the gRPC and YARPC generators. Set False for message-only contracts.",
+        ),
         "_protoc_gen_go": attr.label(
             default = "@org_golang_google_protobuf//cmd/protoc-gen-go",
             executable = True,