diff --git a/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-anthropic/src/main/java/io/agentscope/extensions/model/anthropic/formatter/AnthropicResponseParser.java b/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-anthropic/src/main/java/io/agentscope/extensions/model/anthropic/formatter/AnthropicResponseParser.java
index cc943d020..e223d0d64 100644
--- a/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-anthropic/src/main/java/io/agentscope/extensions/model/anthropic/formatter/AnthropicResponseParser.java
+++ b/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-anthropic/src/main/java/io/agentscope/extensions/model/anthropic/formatter/AnthropicResponseParser.java
@@ -140,6 +140,16 @@ private static ChatResponse parseStreamEvent(RawMessageStreamEvent event, Instan
                                     contentBlocks.add(
                                             TextBlock.builder().text(textDelta.text()).build()));
 
+            deltaEvent
+                    .delta()
+                    .thinking()
+                    .ifPresent(
+                            thinkingDelta ->
+                                    contentBlocks.add(
+                                            ThinkingBlock.builder()
+                                                    .thinking(thinkingDelta.thinking())
+                                                    .build()));
+
             // Input JSON delta (tool calling)
             deltaEvent
                     .delta()
diff --git a/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-anthropic/src/test/java/io/agentscope/extensions/model/anthropic/formatter/AnthropicResponseParserTest.java b/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-anthropic/src/test/java/io/agentscope/extensions/model/anthropic/formatter/AnthropicResponseParserTest.java
index 789a2d49e..d2f7317cb 100644
--- a/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-anthropic/src/test/java/io/agentscope/extensions/model/anthropic/formatter/AnthropicResponseParserTest.java
+++ b/agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-anthropic/src/test/java/io/agentscope/extensions/model/anthropic/formatter/AnthropicResponseParserTest.java
@@ -26,6 +26,7 @@
 
 import com.anthropic.models.messages.ContentBlock;
 import com.anthropic.models.messages.Message;
+import com.anthropic.models.messages.RawContentBlockDeltaEvent;
 import com.anthropic.models.messages.RawMessageStartEvent;
 import com.anthropic.models.messages.RawMessageStreamEvent;
 import com.anthropic.models.messages.Usage;
@@ -316,6 +317,26 @@ void testParseStreamEventMessageStart() throws Exception {
         assertTrue(response.getContent().isEmpty()); // MessageStart has no content
     }
 
+    @Test
+    void testParseStreamEventThinkingDelta() throws Exception {
+        RawContentBlockDeltaEvent deltaEvent =
+                RawContentBlockDeltaEvent.builder()
+                        .index(0)
+                        .thinkingDelta("Let me reason through this.")
+                        .build();
+        RawMessageStreamEvent event = RawMessageStreamEvent.ofContentBlockDelta(deltaEvent);
+
+        Instant startTime = Instant.now();
+        ChatResponse response = invokeParseStreamEvent(event, startTime);
+
+        assertNotNull(response);
+        assertEquals(1, response.getContent().size());
+        ThinkingBlock parsedThinking =
+                assertInstanceOf(ThinkingBlock.class, response.getContent().get(0));
+        assertEquals("Let me reason through this.", parsedThinking.getThinking());
+        assertNull(response.getUsage());
+    }
+
     @Test
     void testParseStreamEventUnknownType() throws Exception {
         // Test unknown event type - should return empty response