diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..dfdb8b7
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1 @@
+*.sh text eol=lf
diff --git a/.github/workflows/pr-validation.yml b/.github/workflows/pr-validation.yml
index b57ec8d..42da255 100644
--- a/.github/workflows/pr-validation.yml
+++ b/.github/workflows/pr-validation.yml
@@ -53,7 +53,6 @@ jobs:
       - uses: actions/checkout@v4
         with:
           fetch-depth: 1
-          submodules: true
           
       - name: Setup Go environment
         uses: actions/setup-go@v5
@@ -74,7 +73,7 @@ jobs:
           go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@$PROTOC_GEN_GO_GRPC
 
       - name: Generate grpc code
-        run: protoc --go_out=. --go-grpc_out=. -I ./submodules/durabletask-protobuf/protos orchestrator_service.proto
+        run: protoc --go_out=. --go-grpc_out=. -I ./vendored/durabletask-protobuf/protos orchestrator_service.proto
 
       - name: Run go vet
         run: go vet ./...
diff --git a/.gitmodules b/.gitmodules
deleted file mode 100644
index e0a2ae7..0000000
--- a/.gitmodules
+++ /dev/null
@@ -1,4 +0,0 @@
-[submodule "submodules/durabletask-protobuf"]
-	path = submodules/durabletask-protobuf
-	url = https://github.com/microsoft/durabletask-protobuf
-	branch = main
diff --git a/CHANGELOG.md b/CHANGELOG.md
index a24df9b..267ccf6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Changed
+
+- Removed the `submodules/durabletask-protobuf` git submodule. The `orchestrator_service.proto` file is now vendored under `vendored/durabletask-protobuf/protos/`, with the source provenance (URL, branch/ref, commit hash) tracked in `vendored/durabletask-protobuf/PROTO_SOURCE_COMMIT_HASH` and a helper script (`vendored/durabletask-protobuf/update-proto.sh`) for refreshing the proto from upstream.
+
 ## [v0.6.0] - 2025-02-05
 
 ### Added
diff --git a/README.md b/README.md
index 9cd8e45..1377d17 100644
--- a/README.md
+++ b/README.md
@@ -247,23 +247,25 @@ Note that each orchestration is represented as a single span with activities, ti
 
 ## Cloning this repository
 
-This repository contains submodules. Be sure to clone it with the option to include submodules. Otherwise you will not be able to generate the protobuf code.
+Clone the repository as you normally would:
 
 ```bash
-git clone --recurse-submodules https://github.com/microsoft/durabletask-go 
+git clone https://github.com/microsoft/durabletask-go
 ```
 
+The protocol buffer definitions used to generate the gRPC bindings are vendored under [`vendored/durabletask-protobuf/protos`](./vendored/durabletask-protobuf/protos). See [`vendored/durabletask-protobuf/README.md`](./vendored/durabletask-protobuf/README.md) for details on how to refresh them from the upstream [microsoft/durabletask-protobuf](https://github.com/microsoft/durabletask-protobuf) repository.
+
 ## Building the project
 
 This project requires go v1.19.x or greater. You can build a standalone executable by simply running `go build` at the project root.
 
 ### Generating protobuf
 
-Use the following command to regenerate the protobuf from the submodule. Use this whenever updating the submodule reference.
+Use the following command to regenerate the protobuf bindings from the vendored proto file. Use this whenever updating the proto file under [`vendored/durabletask-protobuf/protos`](./vendored/durabletask-protobuf/protos).
 
 ```bash
 # NOTE: assumes the .proto file defines: option go_package = "/internal/protos"
-protoc --go_out=. --go-grpc_out=. -I submodules/durabletask-protobuf/protos orchestrator_service.proto
+protoc --go_out=. --go-grpc_out=. -I vendored/durabletask-protobuf/protos orchestrator_service.proto
 ```
 
 ### Generating mocks for testing
diff --git a/submodules/durabletask-protobuf b/submodules/durabletask-protobuf
deleted file mode 160000
index 4207e1d..0000000
--- a/submodules/durabletask-protobuf
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 4207e1dbd14cedc268f69c3befee60fcaad19367
diff --git a/vendored/durabletask-protobuf/PROTO_SOURCE_COMMIT_HASH b/vendored/durabletask-protobuf/PROTO_SOURCE_COMMIT_HASH
new file mode 100644
index 0000000..049687a
--- /dev/null
+++ b/vendored/durabletask-protobuf/PROTO_SOURCE_COMMIT_HASH
@@ -0,0 +1,4 @@
+Source: https://github.com/microsoft/durabletask-protobuf
+Branch: main
+Commit: 4207e1dbd14cedc268f69c3befee60fcaad19367
+URL:    https://github.com/microsoft/durabletask-protobuf/blob/4207e1dbd14cedc268f69c3befee60fcaad19367/protos/orchestrator_service.proto
\ No newline at end of file
diff --git a/vendored/durabletask-protobuf/README.md b/vendored/durabletask-protobuf/README.md
new file mode 100644
index 0000000..36341fe
--- /dev/null
+++ b/vendored/durabletask-protobuf/README.md
@@ -0,0 +1,29 @@
+# Durable Task Protobuf Files
+
+This directory contains the protocol buffer definitions used by the Durable Task Framework Go SDK. The files in this directory are vendored from the [microsoft/durabletask-protobuf](https://github.com/microsoft/durabletask-protobuf) repository.
+
+## Directory Structure
+
+- `protos/` - Contains the vendored proto files
+- `PROTO_SOURCE_COMMIT_HASH` - Records the upstream source URL, branch/ref, and commit hash that the proto files were last synced from
+- `update-proto.sh` - Helper script to refresh the vendored proto file and commit hash from upstream
+
+## Updating the proto files
+
+Run the helper script from the repository root to download the latest `orchestrator_service.proto` from upstream and update `PROTO_SOURCE_COMMIT_HASH`:
+
+```bash
+# Update from the default branch (main)
+./vendored/durabletask-protobuf/update-proto.sh
+
+# Update from a specific branch, tag, or commit SHA
+./vendored/durabletask-protobuf/update-proto.sh <branch-tag-or-sha>
+```
+
+After running the script, regenerate the Go gRPC bindings so that the committed `internal/protos/*.pb.go` files match the updated `.proto`:
+
+```bash
+protoc --go_out=. --go-grpc_out=. -I ./vendored/durabletask-protobuf/protos orchestrator_service.proto
+```
+
+Commit the updated proto file, `PROTO_SOURCE_COMMIT_HASH`, and the regenerated `.pb.go` files together.
diff --git a/vendored/durabletask-protobuf/protos/orchestrator_service.proto b/vendored/durabletask-protobuf/protos/orchestrator_service.proto
new file mode 100644
index 0000000..2ca3755
--- /dev/null
+++ b/vendored/durabletask-protobuf/protos/orchestrator_service.proto
@@ -0,0 +1,617 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+syntax = "proto3";
+
+option csharp_namespace = "Microsoft.DurableTask.Protobuf";
+option java_package = "com.microsoft.durabletask.implementation.protobuf";
+option go_package = "/internal/protos";
+
+import "google/protobuf/timestamp.proto";
+import "google/protobuf/duration.proto";
+import "google/protobuf/wrappers.proto";
+import "google/protobuf/empty.proto";
+
+message OrchestrationInstance {
+    string instanceId = 1;
+    google.protobuf.StringValue executionId = 2;
+}
+
+message ActivityRequest {
+    string name = 1;
+    google.protobuf.StringValue version = 2;
+    google.protobuf.StringValue input = 3;
+    OrchestrationInstance orchestrationInstance = 4;
+    int32 taskId = 5;
+}
+
+message ActivityResponse {
+    string instanceId = 1;
+    int32 taskId = 2;
+    google.protobuf.StringValue result = 3;
+    TaskFailureDetails failureDetails = 4;
+}
+
+message TaskFailureDetails {
+    string errorType = 1;
+    string errorMessage = 2;
+    google.protobuf.StringValue stackTrace = 3;
+    TaskFailureDetails innerFailure = 4;
+    bool isNonRetriable = 5;
+}
+
+enum OrchestrationStatus {
+    ORCHESTRATION_STATUS_RUNNING = 0;
+    ORCHESTRATION_STATUS_COMPLETED = 1;
+    ORCHESTRATION_STATUS_CONTINUED_AS_NEW = 2;
+    ORCHESTRATION_STATUS_FAILED = 3;
+    ORCHESTRATION_STATUS_CANCELED = 4;
+    ORCHESTRATION_STATUS_TERMINATED = 5;
+    ORCHESTRATION_STATUS_PENDING = 6;
+    ORCHESTRATION_STATUS_SUSPENDED = 7;
+}
+
+message ParentInstanceInfo {
+    int32 taskScheduledId = 1;
+    google.protobuf.StringValue name = 2;
+    google.protobuf.StringValue version = 3;
+    OrchestrationInstance orchestrationInstance = 4;
+}
+
+message TraceContext {
+    string traceParent = 1;
+    string spanID = 2 [deprecated=true];
+    google.protobuf.StringValue traceState = 3;
+}
+
+message ExecutionStartedEvent {
+    string name = 1;
+    google.protobuf.StringValue version = 2;
+    google.protobuf.StringValue input = 3;
+    OrchestrationInstance orchestrationInstance = 4;
+    ParentInstanceInfo parentInstance = 5;
+    google.protobuf.Timestamp scheduledStartTimestamp = 6;
+    TraceContext parentTraceContext = 7;
+    google.protobuf.StringValue orchestrationSpanID = 8;
+}
+
+message ExecutionCompletedEvent {
+    OrchestrationStatus orchestrationStatus = 1;
+    google.protobuf.StringValue result = 2;
+    TaskFailureDetails failureDetails = 3;
+}
+
+message ExecutionTerminatedEvent {
+    google.protobuf.StringValue input = 1;
+    bool recurse = 2;
+}
+
+message TaskScheduledEvent {
+    string name = 1;
+    google.protobuf.StringValue version = 2;
+    google.protobuf.StringValue input = 3;
+    TraceContext parentTraceContext = 4;
+}
+
+message TaskCompletedEvent {
+    int32 taskScheduledId = 1;
+    google.protobuf.StringValue result = 2;
+}
+
+message TaskFailedEvent {
+    int32 taskScheduledId = 1;
+    TaskFailureDetails failureDetails = 2;
+}
+
+message SubOrchestrationInstanceCreatedEvent {
+    string instanceId = 1;
+    string name = 2;
+    google.protobuf.StringValue version = 3;
+    google.protobuf.StringValue input = 4;
+    TraceContext parentTraceContext = 5;
+}
+
+message SubOrchestrationInstanceCompletedEvent {
+    int32 taskScheduledId = 1;
+    google.protobuf.StringValue result = 2;
+}
+
+message SubOrchestrationInstanceFailedEvent {
+    int32 taskScheduledId = 1;
+    TaskFailureDetails failureDetails = 2;
+}
+
+message TimerCreatedEvent {
+    google.protobuf.Timestamp fireAt = 1;
+}
+
+message TimerFiredEvent {
+    google.protobuf.Timestamp fireAt = 1;
+    int32 timerId = 2;
+}
+
+message OrchestratorStartedEvent {
+    // No payload data
+}
+
+message OrchestratorCompletedEvent {
+    // No payload data
+}
+
+message EventSentEvent {
+    string instanceId = 1;
+    string name = 2;
+    google.protobuf.StringValue input = 3;
+}
+
+message EventRaisedEvent {
+    string name = 1;
+    google.protobuf.StringValue input = 2;
+}
+
+message GenericEvent {
+    google.protobuf.StringValue data = 1;
+}
+
+message HistoryStateEvent {
+    OrchestrationState orchestrationState = 1;
+}
+
+message ContinueAsNewEvent {
+    google.protobuf.StringValue input = 1;
+}
+
+message ExecutionSuspendedEvent {
+    google.protobuf.StringValue input = 1;
+}
+
+message ExecutionResumedEvent {
+    google.protobuf.StringValue input = 1;
+}
+
+message HistoryEvent {
+    int32 eventId = 1;
+    google.protobuf.Timestamp timestamp = 2;
+    oneof eventType {
+        ExecutionStartedEvent executionStarted = 3;
+        ExecutionCompletedEvent executionCompleted = 4;
+        ExecutionTerminatedEvent executionTerminated = 5;
+        TaskScheduledEvent taskScheduled = 6;
+        TaskCompletedEvent taskCompleted = 7;
+        TaskFailedEvent taskFailed = 8;
+        SubOrchestrationInstanceCreatedEvent subOrchestrationInstanceCreated = 9;
+        SubOrchestrationInstanceCompletedEvent subOrchestrationInstanceCompleted = 10;
+        SubOrchestrationInstanceFailedEvent subOrchestrationInstanceFailed = 11;
+        TimerCreatedEvent timerCreated = 12;
+        TimerFiredEvent timerFired = 13;
+        OrchestratorStartedEvent orchestratorStarted = 14;
+        OrchestratorCompletedEvent orchestratorCompleted = 15;
+        EventSentEvent eventSent = 16;
+        EventRaisedEvent eventRaised = 17;
+        GenericEvent genericEvent = 18;
+        HistoryStateEvent historyState = 19;
+        ContinueAsNewEvent continueAsNew = 20;
+        ExecutionSuspendedEvent executionSuspended = 21;
+        ExecutionResumedEvent executionResumed = 22;
+    }
+}
+
+message ScheduleTaskAction {
+    string name = 1;
+    google.protobuf.StringValue version = 2;
+    google.protobuf.StringValue input = 3;
+}
+
+message CreateSubOrchestrationAction {
+    string instanceId = 1;
+    string name = 2;
+    google.protobuf.StringValue version = 3;
+    google.protobuf.StringValue input = 4;
+}
+
+message CreateTimerAction {
+    google.protobuf.Timestamp fireAt = 1;
+}
+
+message SendEventAction {
+    OrchestrationInstance instance = 1;
+    string name = 2;
+    google.protobuf.StringValue data = 3;
+}
+
+message CompleteOrchestrationAction {
+    OrchestrationStatus orchestrationStatus = 1;
+    google.protobuf.StringValue result = 2;
+    google.protobuf.StringValue details = 3;
+    google.protobuf.StringValue newVersion = 4;
+    repeated HistoryEvent carryoverEvents = 5;
+    TaskFailureDetails failureDetails = 6;
+}
+
+message TerminateOrchestrationAction {
+    string instanceId = 1;
+    google.protobuf.StringValue reason = 2;
+    bool recurse = 3;
+}
+
+message OrchestratorAction {
+    int32 id = 1;
+    oneof orchestratorActionType {
+        ScheduleTaskAction scheduleTask = 2;
+        CreateSubOrchestrationAction createSubOrchestration = 3;
+        CreateTimerAction createTimer = 4;
+        SendEventAction sendEvent = 5;
+        CompleteOrchestrationAction completeOrchestration = 6;
+        TerminateOrchestrationAction terminateOrchestration = 7;
+    }
+}
+
+message OrchestratorRequest {
+    string instanceId = 1;
+    google.protobuf.StringValue executionId = 2;
+    repeated HistoryEvent pastEvents = 3;
+    repeated HistoryEvent newEvents = 4;
+    OrchestratorEntityParameters entityParameters = 5;
+}
+
+message OrchestratorResponse {
+    string instanceId = 1;
+    repeated OrchestratorAction actions = 2;
+    google.protobuf.StringValue customStatus = 3;
+}
+
+message CreateInstanceRequest {
+    string instanceId = 1;
+    string name = 2;
+    google.protobuf.StringValue version = 3;
+    google.protobuf.StringValue input = 4;
+    google.protobuf.Timestamp scheduledStartTimestamp = 5;
+    OrchestrationIdReusePolicy orchestrationIdReusePolicy = 6;
+}
+
+message OrchestrationIdReusePolicy {
+    repeated OrchestrationStatus operationStatus = 1;
+    CreateOrchestrationAction action = 2;
+}
+
+enum CreateOrchestrationAction {
+    ERROR = 0;
+    IGNORE = 1;
+    TERMINATE = 2;
+}
+
+message CreateInstanceResponse {
+    string instanceId = 1;
+}
+
+message GetInstanceRequest {
+    string instanceId = 1;
+    bool getInputsAndOutputs = 2;
+}
+
+message GetInstanceResponse {
+    bool exists = 1;
+    OrchestrationState orchestrationState = 2;
+}
+
+message RewindInstanceRequest {
+    string instanceId = 1;
+    google.protobuf.StringValue reason = 2;
+}
+
+message RewindInstanceResponse {
+    // Empty for now. Using explicit type incase we want to add content later.
+}
+
+message OrchestrationState {
+    string instanceId = 1;
+    string name = 2;
+    google.protobuf.StringValue version = 3;
+    OrchestrationStatus orchestrationStatus = 4;
+    google.protobuf.Timestamp scheduledStartTimestamp = 5;
+    google.protobuf.Timestamp createdTimestamp = 6;
+    google.protobuf.Timestamp lastUpdatedTimestamp = 7;
+    google.protobuf.StringValue input = 8;
+    google.protobuf.StringValue output = 9;
+    google.protobuf.StringValue customStatus = 10;
+    TaskFailureDetails failureDetails = 11;
+}
+
+message RaiseEventRequest {
+    string instanceId = 1;
+    string name = 2;
+    google.protobuf.StringValue input = 3;
+}
+
+message RaiseEventResponse {
+    // No payload
+}
+
+message TerminateRequest {
+    string instanceId = 1;
+    google.protobuf.StringValue output = 2;
+    bool recursive = 3;
+}
+
+message TerminateResponse {
+    // No payload
+}
+
+message SuspendRequest {
+    string instanceId = 1;
+    google.protobuf.StringValue reason = 2;
+}
+
+message SuspendResponse {
+    // No payload
+}
+
+message ResumeRequest {
+    string instanceId = 1;
+    google.protobuf.StringValue reason = 2;
+}
+
+message ResumeResponse {
+    // No payload
+}
+
+message QueryInstancesRequest {
+    InstanceQuery query = 1;
+}
+
+message InstanceQuery{
+    repeated OrchestrationStatus runtimeStatus = 1;
+    google.protobuf.Timestamp createdTimeFrom = 2;
+    google.protobuf.Timestamp createdTimeTo = 3;
+    repeated google.protobuf.StringValue taskHubNames = 4;
+    int32 maxInstanceCount = 5;
+    google.protobuf.StringValue continuationToken = 6;
+    google.protobuf.StringValue instanceIdPrefix = 7;
+    bool fetchInputsAndOutputs = 8;
+}
+
+message QueryInstancesResponse {
+    repeated OrchestrationState orchestrationState = 1;
+    google.protobuf.StringValue continuationToken = 2;
+}
+
+message PurgeInstancesRequest {
+    oneof request {
+        string instanceId = 1;
+        PurgeInstanceFilter purgeInstanceFilter = 2;
+    }
+    bool recursive = 3;
+}
+
+message PurgeInstanceFilter {
+    google.protobuf.Timestamp createdTimeFrom = 1;
+    google.protobuf.Timestamp createdTimeTo = 2;
+    repeated OrchestrationStatus runtimeStatus = 3;
+}
+
+message PurgeInstancesResponse {
+    int32 deletedInstanceCount = 1;
+}
+
+message CreateTaskHubRequest {
+    bool recreateIfExists = 1;
+}
+
+message CreateTaskHubResponse {
+    //no playload
+}
+
+message DeleteTaskHubRequest {
+    //no playload
+}
+
+message DeleteTaskHubResponse {
+    //no playload
+}
+
+message SignalEntityRequest {
+    string instanceId = 1;
+    string name = 2;
+    google.protobuf.StringValue input = 3;
+    string requestId = 4;
+    google.protobuf.Timestamp scheduledTime = 5;
+}
+
+message SignalEntityResponse {
+     // no payload
+}
+
+message GetEntityRequest
+{
+    string instanceId = 1;
+    bool includeState = 2;
+}
+
+message GetEntityResponse
+{
+    bool exists = 1;
+    EntityMetadata entity = 2;
+}
+
+message EntityQuery
+{
+    google.protobuf.StringValue instanceIdStartsWith = 1;
+    google.protobuf.Timestamp lastModifiedFrom = 2;
+    google.protobuf.Timestamp lastModifiedTo = 3;
+    bool includeState = 4;
+    bool includeTransient = 5;
+    google.protobuf.Int32Value pageSize = 6;
+    google.protobuf.StringValue continuationToken = 7;
+}
+
+message QueryEntitiesRequest
+{
+    EntityQuery query = 1;
+}
+
+message QueryEntitiesResponse
+{
+    repeated EntityMetadata entities = 1;
+    google.protobuf.StringValue continuationToken = 2;
+}
+
+message EntityMetadata
+{
+    string instanceId = 1;
+    google.protobuf.Timestamp lastModifiedTime = 2;
+    int32 backlogQueueSize = 3;
+    google.protobuf.StringValue lockedBy = 4;
+    google.protobuf.StringValue serializedState = 5;
+}
+
+message CleanEntityStorageRequest
+{
+    google.protobuf.StringValue continuationToken = 1;
+    bool removeEmptyEntities = 2;
+    bool releaseOrphanedLocks = 3;
+}
+
+message CleanEntityStorageResponse
+{
+    google.protobuf.StringValue continuationToken = 1;
+    int32 emptyEntitiesRemoved = 2;
+    int32 orphanedLocksReleased = 3;
+}
+
+message OrchestratorEntityParameters
+{
+    google.protobuf.Duration entityMessageReorderWindow = 1;
+}
+
+message EntityBatchRequest {
+    string instanceId = 1;
+    google.protobuf.StringValue entityState = 2;
+    repeated OperationRequest operations = 3;
+}
+
+message EntityBatchResult {
+    repeated OperationResult results = 1;
+    repeated OperationAction actions = 2;
+    google.protobuf.StringValue entityState = 3;
+    TaskFailureDetails failureDetails = 4;
+}
+
+message OperationRequest {
+    string operation = 1;
+    string requestId = 2;
+    google.protobuf.StringValue input = 3;
+}
+
+message OperationResult {
+    oneof resultType {
+        OperationResultSuccess success = 1;
+        OperationResultFailure failure = 2;
+    }
+}
+
+message OperationResultSuccess {
+    google.protobuf.StringValue result = 1;
+}
+
+message OperationResultFailure {
+    TaskFailureDetails failureDetails = 1;
+}
+
+message OperationAction {
+    int32 id = 1;
+    oneof operationActionType {
+        SendSignalAction sendSignal = 2;
+        StartNewOrchestrationAction startNewOrchestration = 3;
+    }
+}
+
+message SendSignalAction {
+    string instanceId = 1;
+    string name = 2;
+    google.protobuf.StringValue input = 3;
+    google.protobuf.Timestamp scheduledTime = 4;
+}
+
+message StartNewOrchestrationAction {
+    string instanceId = 1;
+    string name = 2;
+    google.protobuf.StringValue version = 3;
+    google.protobuf.StringValue input = 4;
+    google.protobuf.Timestamp scheduledTime = 5;
+}
+
+service TaskHubSidecarService {
+    // Sends a hello request to the sidecar service.
+    rpc Hello(google.protobuf.Empty) returns (google.protobuf.Empty);
+
+    // Starts a new orchestration instance.
+    rpc StartInstance(CreateInstanceRequest) returns (CreateInstanceResponse);
+
+    // Gets the status of an existing orchestration instance.
+    rpc GetInstance(GetInstanceRequest) returns (GetInstanceResponse);
+
+    // Rewinds an orchestration instance to last known good state and replays from there.
+    rpc RewindInstance(RewindInstanceRequest) returns (RewindInstanceResponse);
+
+    // Waits for an orchestration instance to reach a running or completion state.
+    rpc WaitForInstanceStart(GetInstanceRequest) returns (GetInstanceResponse);
+    
+    // Waits for an orchestration instance to reach a completion state (completed, failed, terminated, etc.).
+    rpc WaitForInstanceCompletion(GetInstanceRequest) returns (GetInstanceResponse);
+
+    // Raises an event to a running orchestration instance.
+    rpc RaiseEvent(RaiseEventRequest) returns (RaiseEventResponse);
+    
+    // Terminates a running orchestration instance.
+    rpc TerminateInstance(TerminateRequest) returns (TerminateResponse);
+    
+    // Suspends a running orchestration instance.
+    rpc SuspendInstance(SuspendRequest) returns (SuspendResponse);
+
+    // Resumes a suspended orchestration instance.
+    rpc ResumeInstance(ResumeRequest) returns (ResumeResponse);
+
+    // rpc DeleteInstance(DeleteInstanceRequest) returns (DeleteInstanceResponse);
+
+    rpc QueryInstances(QueryInstancesRequest) returns (QueryInstancesResponse);
+    rpc PurgeInstances(PurgeInstancesRequest) returns (PurgeInstancesResponse);
+
+    rpc GetWorkItems(GetWorkItemsRequest) returns (stream WorkItem);
+    rpc CompleteActivityTask(ActivityResponse) returns (CompleteTaskResponse);
+    rpc CompleteOrchestratorTask(OrchestratorResponse) returns (CompleteTaskResponse);
+    rpc CompleteEntityTask(EntityBatchResult) returns (CompleteTaskResponse);
+
+    // Deletes and Creates the necessary resources for the orchestration service and the instance store
+    rpc CreateTaskHub(CreateTaskHubRequest) returns (CreateTaskHubResponse);
+
+    // Deletes the resources for the orchestration service and optionally the instance store
+    rpc DeleteTaskHub(DeleteTaskHubRequest) returns (DeleteTaskHubResponse);
+
+    // sends a signal to an entity
+    rpc SignalEntity(SignalEntityRequest) returns (SignalEntityResponse);
+
+    // get information about a specific entity
+    rpc GetEntity(GetEntityRequest) returns (GetEntityResponse);
+
+    // query entities
+    rpc QueryEntities(QueryEntitiesRequest) returns (QueryEntitiesResponse);
+
+    // clean entity storage
+    rpc CleanEntityStorage(CleanEntityStorageRequest) returns (CleanEntityStorageResponse);
+}
+
+message GetWorkItemsRequest {
+    // No parameters currently
+}
+
+message WorkItem {
+    oneof request {
+        OrchestratorRequest orchestratorRequest = 1;
+        ActivityRequest activityRequest = 2;
+        EntityBatchRequest entityRequest = 3;
+    }
+}
+
+message CompleteTaskResponse {
+    // No payload
+}
\ No newline at end of file
diff --git a/vendored/durabletask-protobuf/update-proto.sh b/vendored/durabletask-protobuf/update-proto.sh
new file mode 100755
index 0000000..b5b22ab
--- /dev/null
+++ b/vendored/durabletask-protobuf/update-proto.sh
@@ -0,0 +1,69 @@
+#!/usr/bin/env bash
+# Downloads the latest orchestrator_service.proto from the
+# microsoft/durabletask-protobuf repository and writes provenance
+# information (source URL, branch/ref, commit hash, file URL) to
+# PROTO_SOURCE_COMMIT_HASH.
+#
+# Usage:
+#   ./vendored/durabletask-protobuf/update-proto.sh [ref]
+#
+# `ref` may be a branch name, tag name, or commit SHA.
+# If omitted, "main" is used.
+
+set -euo pipefail
+
+REF="${1:-main}"
+REPO="microsoft/durabletask-protobuf"
+REPO_URL="https://github.com/${REPO}"
+PROTO_PATH="protos/orchestrator_service.proto"
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROTO_DIR="${SCRIPT_DIR}/protos"
+HASH_FILE="${SCRIPT_DIR}/PROTO_SOURCE_COMMIT_HASH"
+
+mkdir -p "${PROTO_DIR}"
+
+CURL_AUTH=()
+if [[ -n "${GITHUB_TOKEN:-}" ]]; then
+    CURL_AUTH=(-H "Authorization: Bearer ${GITHUB_TOKEN}")
+fi
+
+echo "Resolving latest commit for ${PROTO_PATH} on ${REPO}@${REF}..."
+COMMIT_API_URL="https://api.github.com/repos/${REPO}/commits?path=${PROTO_PATH}&sha=${REF}&per_page=1"
+COMMIT_RESPONSE=$(curl -fsSL \
+    "${CURL_AUTH[@]}" \
+    -H "Accept: application/vnd.github.v3+json" \
+    "${COMMIT_API_URL}")
+
+# Extract the first "sha": "<hash>" value from the JSON response.
+# Use sed -nE so a missing match leaves COMMIT_HASH empty and the
+# validation block below can emit a clear error, instead of the
+# pipeline aborting silently under `set -euo pipefail`.
+COMMIT_HASH=$(printf '%s' "${COMMIT_RESPONSE}" \
+    | sed -nE 's/.*"sha"[[:space:]]*:[[:space:]]*"([^"]+)".*/\1/p' \
+    | head -n 1)
+
+if [[ -z "${COMMIT_HASH}" ]]; then
+    echo "Failed to resolve commit hash from ${COMMIT_API_URL}" >&2
+    echo "Response was:" >&2
+    printf '%s\n' "${COMMIT_RESPONSE}" >&2
+    exit 1
+fi
+
+echo "Downloading ${PROTO_PATH}@${COMMIT_HASH}..."
+curl -fsSL \
+    "https://raw.githubusercontent.com/${REPO}/${COMMIT_HASH}/${PROTO_PATH}" \
+    -o "${PROTO_DIR}/orchestrator_service.proto"
+
+cat > "${HASH_FILE}" <<EOF
+Source: ${REPO_URL}
+Branch: ${REF}
+Commit: ${COMMIT_HASH}
+URL:    ${REPO_URL}/blob/${COMMIT_HASH}/${PROTO_PATH}
+EOF
+
+echo "Updated ${PROTO_DIR}/orchestrator_service.proto"
+echo "Recorded provenance for commit ${COMMIT_HASH} in ${HASH_FILE}"
+echo
+echo "Next step: regenerate the Go bindings:"
+echo "  protoc --go_out=. --go-grpc_out=. -I ./vendored/durabletask-protobuf/protos orchestrator_service.proto"
\ No newline at end of file