fix: handle content.thinking

src/claude_code_sdk/_internal/client.py

@@ -11,6 +11,7 @@ from ..types import (
     ResultMessage,
     SystemMessage,
     TextBlock,
+    ThinkingBlock,
     ToolResultBlock,
     ToolUseBlock,
     UserMessage,
@@ -55,6 +56,13 @@ class InternalClient:
                     match block["type"]:
                         case "text":
                             content_blocks.append(TextBlock(text=block["text"]))
+                        case "thinking":
+                            content_blocks.append(
+                                ThinkingBlock(
+                                    thinking=block["thinking"],
+                                    signature=block["signature"],
+                                )
+                            )
                         case "tool_use":
                             content_blocks.append(
                                 ToolUseBlock(

src/claude_code_sdk/types.py

@@ -26,6 +26,14 @@ class TextBlock:
     text: str
 
 
+@dataclass
+class ThinkingBlock:
+    """Thinking content block."""
+
+    thinking: str
+    signature: str
+
+
 @dataclass
 class ToolUseBlock:
     """Tool use content block."""

tests/test_types.py

@@ -5,7 +5,13 @@ from claude_code_sdk import (
     ClaudeCodeOptions,
     ResultMessage,
 )
-from claude_code_sdk.types import TextBlock, ToolResultBlock, ToolUseBlock, UserMessage
+from claude_code_sdk.types import (
+    TextBlock,
+    ThinkingBlock,
+    ToolResultBlock,
+    ToolUseBlock,
+    UserMessage,
+)
 
 
 class TestMessageTypes:
@@ -23,6 +29,14 @@ class TestMessageTypes:
         assert len(msg.content) == 1
         assert msg.content[0].text == "Hello, human!"
 
+    def test_assistant_message_with_thinking(self):
+        """Test creating an AssistantMessage with thinking content."""
+        thinking_block = ThinkingBlock(thinking="I'm thinking...", signature="sig-123")
+        msg = AssistantMessage(content=[thinking_block])
+        assert len(msg.content) == 1
+        assert msg.content[0].thinking == "I'm thinking..."
+        assert msg.content[0].signature == "sig-123"
+
     def test_tool_use_block(self):
         """Test creating a ToolUseBlock."""
         block = ToolUseBlock(