diff --git a/agentscope-extensions/agentscope-extensions-protocol/agentscope-extensions-agui/src/main/java/io/agentscope/core/agui/adapter/AguiAgentAdapter.java b/agentscope-extensions/agentscope-extensions-protocol/agentscope-extensions-agui/src/main/java/io/agentscope/core/agui/adapter/AguiAgentAdapter.java
index ba3aa2b2cc..ed11481c97 100644
--- a/agentscope-extensions/agentscope-extensions-protocol/agentscope-extensions-agui/src/main/java/io/agentscope/core/agui/adapter/AguiAgentAdapter.java
+++ b/agentscope-extensions/agentscope-extensions-protocol/agentscope-extensions-agui/src/main/java/io/agentscope/core/agui/adapter/AguiAgentAdapter.java
@@ -79,6 +79,7 @@ public class AguiAgentAdapter {
     public static final String RUNTIME_CONTEXT_CONTEXT_KEY = "agui.context";
     public static final String RUNTIME_CONTEXT_STATE_KEY = "agui.state";
     public static final String RUNTIME_CONTEXT_FORWARDED_PROPS_KEY = "agui.forwardedProps";
+    public static final String FORWARDED_PROP_USER_ID_KEY = "userId";
 
     private final Agent agent;
     private final AguiAdapterConfig config;
@@ -162,6 +163,7 @@ public Flux<AguiEvent> run(RunAgentInput input) {
     private RuntimeContext buildRuntimeContext(RunAgentInput input) {
         return RuntimeContext.builder()
                 .sessionId(input.getThreadId())
+                .userId(normalizeUserId(input.getForwardedProp(FORWARDED_PROP_USER_ID_KEY)))
                 .put(RunAgentInput.class, input)
                 .put(RUNTIME_CONTEXT_THREAD_ID_KEY, input.getThreadId())
                 .put(RUNTIME_CONTEXT_RUN_ID_KEY, input.getRunId())
@@ -173,6 +175,18 @@ private RuntimeContext buildRuntimeContext(RunAgentInput input) {
                 .build();
     }
 
+    private static String normalizeUserId(Object value) {
+        if (value == null) {
+            return null;
+        }
+        String userId = value.toString();
+        if (userId == null) {
+            return null;
+        }
+        userId = userId.trim();
+        return userId.isEmpty() ? null : userId;
+    }
+
     private ToolInjection injectFrontendTools(RunAgentInput input) {
         if (!input.hasTools()) {
             return ToolInjection.empty();
diff --git a/agentscope-extensions/agentscope-extensions-protocol/agentscope-extensions-agui/src/test/java/io/agentscope/core/agui/adapter/AguiAgentAdapterTest.java b/agentscope-extensions/agentscope-extensions-protocol/agentscope-extensions-agui/src/test/java/io/agentscope/core/agui/adapter/AguiAgentAdapterTest.java
index 2d96f21ffb..431aa1099b 100644
--- a/agentscope-extensions/agentscope-extensions-protocol/agentscope-extensions-agui/src/test/java/io/agentscope/core/agui/adapter/AguiAgentAdapterTest.java
+++ b/agentscope-extensions/agentscope-extensions-protocol/agentscope-extensions-agui/src/test/java/io/agentscope/core/agui/adapter/AguiAgentAdapterTest.java
@@ -70,6 +70,71 @@ void setUp() {
         adapter = new AguiAgentAdapter(mockAgent, AguiAdapterConfig.defaultConfig());
     }
 
+    @Test
+    void testRunSetsUserIdFromForwardedPropsIntoRuntimeContext() {
+        ArgumentCaptor<RuntimeContext> contextCaptor =
+                ArgumentCaptor.forClass(RuntimeContext.class);
+        when(mockAgent.stream(anyList(), any(StreamOptions.class), contextCaptor.capture()))
+                .thenReturn(Flux.empty());
+
+        RunAgentInput input =
+                RunAgentInput.builder()
+                        .threadId("thread-user")
+                        .runId("run-user")
+                        .messages(List.of(AguiMessage.userMessage("msg-1", "Hello")))
+                        .forwardedProps(
+                                Map.of(AguiAgentAdapter.FORWARDED_PROP_USER_ID_KEY, "user-123"))
+                        .build();
+
+        adapter.run(input).collectList().block();
+
+        RuntimeContext context = contextCaptor.getValue();
+        assertEquals("user-123", context.getUserId());
+        assertSame(input.getForwardedProps(), context.get("agui.forwardedProps"));
+    }
+
+    @Test
+    void testRunConvertsNonStringUserIdFromForwardedProps() {
+        ArgumentCaptor<RuntimeContext> contextCaptor =
+                ArgumentCaptor.forClass(RuntimeContext.class);
+        when(mockAgent.stream(anyList(), any(StreamOptions.class), contextCaptor.capture()))
+                .thenReturn(Flux.empty());
+
+        RunAgentInput input =
+                RunAgentInput.builder()
+                        .threadId("thread-user-long")
+                        .runId("run-user-long")
+                        .messages(List.of(AguiMessage.userMessage("msg-1", "Hello")))
+                        .forwardedProps(Map.of(AguiAgentAdapter.FORWARDED_PROP_USER_ID_KEY, 12345L))
+                        .build();
+
+        adapter.run(input).collectList().block();
+
+        RuntimeContext context = contextCaptor.getValue();
+        assertEquals("12345", context.getUserId());
+    }
+
+    @Test
+    void testRunKeepsUserIdNullWhenForwardedPropsMissingUserId() {
+        ArgumentCaptor<RuntimeContext> contextCaptor =
+                ArgumentCaptor.forClass(RuntimeContext.class);
+        when(mockAgent.stream(anyList(), any(StreamOptions.class), contextCaptor.capture()))
+                .thenReturn(Flux.empty());
+
+        RunAgentInput input =
+                RunAgentInput.builder()
+                        .threadId("thread-no-user")
+                        .runId("run-no-user")
+                        .messages(List.of(AguiMessage.userMessage("msg-1", "Hello")))
+                        .forwardedProps(Map.of("tenant", "demo"))
+                        .build();
+
+        adapter.run(input).collectList().block();
+
+        RuntimeContext context = contextCaptor.getValue();
+        assertNull(context.getUserId());
+    }
+
     @Test
     void testRunInjectsRunInputIntoRuntimeContext() {
         ArgumentCaptor<RuntimeContext> contextCaptor =