diff --git a/vllm/entrypoints/anthropic/protocol.py b/vllm/entrypoints/anthropic/protocol.py
index bbf1ffc27..af9430e78 100644
--- a/vllm/entrypoints/anthropic/protocol.py
+++ b/vllm/entrypoints/anthropic/protocol.py
@@ -40,6 +40,7 @@ class AnthropicContentBlock(BaseModel):
     source: dict[str, Any] | None = None
     # For tool use/result
     id: str | None = None
+    tool_use_id: str | None = None
     name: str | None = None
     input: dict[str, Any] | None = None
     content: str | list[dict[str, Any]] | None = None
diff --git a/vllm/entrypoints/anthropic/serving.py b/vllm/entrypoints/anthropic/serving.py
index 7f53b1ef3..8fb347aab 100644
--- a/vllm/entrypoints/anthropic/serving.py
+++ b/vllm/entrypoints/anthropic/serving.py
@@ -139,7 +139,7 @@ class AnthropicServingMessages(OpenAIServingChat):
                             openai_messages.append(
                                 {
                                     "role": "tool",
-                                    "tool_call_id": block.id or "",
+                                    "tool_call_id": block.tool_use_id or "",
                                     "content": str(block.content)
                                     if block.content
                                     else "",