diff --git a/inc/usersim/nt_process_info.h b/inc/usersim/nt_process_info.h
new file mode 100644
index 0000000..2c049a2
--- /dev/null
+++ b/inc/usersim/nt_process_info.h
@@ -0,0 +1,49 @@
+// Copyright (c) Microsoft Corporation
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+// Native NT process-telemetry query definitions used to implement (usersim's PsGetProcessStartKey)
+// and to verify (eBPF for Windows api_test) the process start key. Per the official documentation
+// these types "have no associated import library or header file", so they must be declared locally;
+// this shared header keeps usersim and its consumers from maintaining divergent private copies.
+//
+// This is a leaf header: it only declares native NT types and depends solely on the basic Windows
+// integer/handle/status types (ULONG, ULONG64, HANDLE, PVOID, PULONG, NTSTATUS, NTAPI). Include it
+// after <windows.h> (and, where NTSTATUS is not otherwise available, a header that provides it).
+//
+// https://learn.microsoft.com/en-us/windows/win32/devnotes/process_telemetry_id_information_type
+
+typedef struct _PROCESS_TELEMETRY_ID_INFORMATION
+{
+    ULONG HeaderSize;
+    ULONG ProcessId;
+    ULONG64 ProcessStartKey;
+    ULONG64 CreateTime;
+    ULONG64 CreateInterruptTime;
+    ULONG64 CreateUnbiasedInterruptTime;
+    ULONG64 ProcessSequenceNumber;
+    ULONG64 SessionCreateTime;
+    ULONG SessionId;
+    ULONG BootId;
+    ULONG ImageChecksum;
+    ULONG ImageTimeDateStamp;
+    ULONG UserSidOffset;
+    ULONG ImagePathOffset;
+    ULONG PackageNameOffset;
+    ULONG RelativeAppNameOffset;
+    ULONG CommandLineOffset;
+} PROCESS_TELEMETRY_ID_INFORMATION, *PPROCESS_TELEMETRY_ID_INFORMATION;
+
+// ProcessInformationClass value used to query PROCESS_TELEMETRY_ID_INFORMATION.
+enum
+{
+    ProcessTelemetryIdInformation = 64
+};
+
+typedef NTSTATUS(NTAPI* NtQueryInformationProcess_t)(
+    _In_ HANDLE ProcessHandle,
+    _In_ ULONG ProcessInformationClass,
+    _Out_writes_bytes_(ProcessInformationLength) PVOID ProcessInformation,
+    _In_ ULONG ProcessInformationLength,
+    _Out_opt_ PULONG ReturnLength);
diff --git a/src/ps.cpp b/src/ps.cpp
index 89c9148..14df835 100644
--- a/src/ps.cpp
+++ b/src/ps.cpp
@@ -3,6 +3,7 @@
 
 #include "kernel_um.h"
 #include "platform.h"
+#include "usersim/nt_process_info.h"
 #include "usersim/ps.h"
 
 #include <assert.h>
@@ -19,45 +20,6 @@ _IRQL_requires_max_(DISPATCH_LEVEL) NTKERNELAPI HANDLE PsGetCurrentThreadId()
     return (HANDLE)(uintptr_t)GetCurrentThreadId();
 }
 
-typedef struct _PROCESS_TELEMETRY_ID_INFORMATION
-{
-    ULONG HeaderSize;
-    ULONG ProcessId;
-    ULONG64 ProcessStartKey;
-    ULONG64 CreateTime;
-    ULONG64 CreateInterruptTime;
-    ULONG64 CreateUnbiasedInterruptTime;
-    ULONG64 ProcessSequenceNumber;
-    ULONG64 SessionCreateTime;
-    ULONG SessionId;
-    ULONG BootId;
-    ULONG ImageChecksum;
-    ULONG ImageTimeDateStamp;
-    ULONG UserSidOffset;
-    ULONG ImagePathOffset;
-    ULONG PackageNameOffset;
-    ULONG RelativeAppNameOffset;
-    ULONG CommandLineOffset;
-} PROCESS_TELEMETRY_ID_INFORMATION, *PPROCESS_TELEMETRY_ID_INFORMATION;
-
-typedef enum _PROCESSINFOCLASS
-{
-    ProcessBasicInformation = 0,
-    ProcessDebugPort = 7,
-    ProcessWow64Information = 26,
-    ProcessImageFileName = 27,
-    ProcessBreakOnTermination = 29,
-    ProcessTelemetryIdInformation = 64,
-    ProcessSubsystemInformation = 75
-} PROCESSINFOCLASS;
-
-typedef NTSTATUS (NTAPI *NtQueryInformationProcess_t)(
-    _In_ HANDLE ProcessHandle,
-    _In_ PROCESSINFOCLASS ProcessInformationClass,
-    _Out_writes_bytes_(ProcessInformationLength) PVOID ProcessInformation,
-    _In_ ULONG ProcessInformationLength,
-    _Out_opt_ PULONG ReturnLength);
-
 static PGETPROCESSSTARTKEY _usersim_get_process_start_key_callback = nullptr;
 USERSIM_API
 void
diff --git a/src/usersim.vcxproj b/src/usersim.vcxproj
index b828daf..bce23c0 100644
--- a/src/usersim.vcxproj
+++ b/src/usersim.vcxproj
@@ -131,6 +131,7 @@
     <ClInclude Include="ndis.h" />
     <ClInclude Include="net_platform.h" />
     <ClInclude Include="nmr_impl.h" />
+    <ClInclude Include="..\inc\usersim\nt_process_info.h" />
     <ClInclude Include="..\inc\usersim\ps.h" />
     <ClInclude Include="..\inc\usersim\rtl.h" />
     <ClInclude Include="..\inc\usersim\se.h" />