feat: ChatMessage.to_openai_dict_format - add require_tool_call_ids parameter (#9481)

Author: anakin87

haystack/dataclasses/chat_message.py

@@ -388,9 +388,19 @@ def from_dict(cls, data: Dict[str, Any]) -> "ChatMessage":
 
         raise ValueError(f"Missing 'content' or '_content' in serialized ChatMessage: `{data}`")
 
-    def to_openai_dict_format(self) -> Dict[str, Any]:
+    def to_openai_dict_format(self, require_tool_call_ids: bool = True) -> Dict[str, Any]:
         """
         Convert a ChatMessage to the dictionary format expected by OpenAI's Chat API.
+
+        :param require_tool_call_ids:
+            If True (default), enforces that each Tool Call includes a non-null `id` attribute.
+            Set to False to allow Tool Calls without `id`, which may be suitable for shallow OpenAI-compatible APIs.
+        :returns:
+            The ChatMessage in the format expected by OpenAI's Chat API.
+
+        :raises ValueError:
+            If the message format is invalid, or if `require_tool_call_ids` is True and any Tool Call is missing an
+            `id` attribute.
         """
         text_contents = self.texts
         tool_calls = self.tool_calls
@@ -411,28 +421,32 @@ def to_openai_dict_format(self) -> Dict[str, Any]:
 
         if tool_call_results:
             result = tool_call_results[0]
-            if result.origin.id is None:
-                raise ValueError("`ToolCall` must have a non-null `id` attribute to be used with OpenAI.")
             openai_msg["content"] = result.result
-            openai_msg["tool_call_id"] = result.origin.id
+            if result.origin.id is not None:
+                openai_msg["tool_call_id"] = result.origin.id
+            elif require_tool_call_ids:
+                raise ValueError("`ToolCall` must have a non-null `id` attribute to be used with OpenAI.")
+
             # OpenAI does not provide a way to communicate errors in tool invocations, so we ignore the error field
             return openai_msg
 
         if text_contents:
             openai_msg["content"] = text_contents[0]
         if tool_calls:
             openai_tool_calls = []
+
             for tc in tool_calls:
-                if tc.id is None:
+                openai_tool_call = {
+                    "type": "function",
+                    # We disable ensure_ascii so special chars like emojis are not converted
+                    "function": {"name": tc.tool_name, "arguments": json.dumps(tc.arguments, ensure_ascii=False)},
+                }
+                if tc.id is not None:
+                    openai_tool_call["id"] = tc.id
+                elif require_tool_call_ids:
                     raise ValueError("`ToolCall` must have a non-null `id` attribute to be used with OpenAI.")
-                openai_tool_calls.append(
-                    {
-                        "id": tc.id,
-                        "type": "function",
-                        # We disable ensure_ascii so special chars like emojis are not converted
-                        "function": {"name": tc.tool_name, "arguments": json.dumps(tc.arguments, ensure_ascii=False)},
-                    }
-                )
+                openai_tool_calls.append(openai_tool_call)
+
             openai_msg["tool_calls"] = openai_tool_calls
         return openai_msg
 

releasenotes/notes/to_openai_dict_format-require-tool-call-ids-9e40a5751740ad89.yaml

@@ -0,0 +1,7 @@
+---
+enhancements:
+  - |
+    Add a new parameter `require_tool_call_ids` to `ChatMessage.to_openai_dict_format`.
+    The default is `True`, for compatibility with OpenAI's Chat API: if the `id` field is missing in a Tool Call,
+    an error is raised.  Using `False` is useful for shallow OpenAI-compatible APIs, where the `id` field is not
+    required.

test/dataclasses/test_chat_message.py

@@ -342,14 +342,31 @@ def test_to_openai_dict_format_invalid():
     with pytest.raises(ValueError):
         message.to_openai_dict_format()
 
+
+def test_to_openai_dict_format_require_tool_call_ids():
     tool_call_null_id = ToolCall(id=None, tool_name="weather", arguments={"city": "Paris"})
     message = ChatMessage.from_assistant(tool_calls=[tool_call_null_id])
     with pytest.raises(ValueError):
-        message.to_openai_dict_format()
+        message.to_openai_dict_format(require_tool_call_ids=True)
 
     message = ChatMessage.from_tool(tool_result="result", origin=tool_call_null_id)
     with pytest.raises(ValueError):
-        message.to_openai_dict_format()
+        message.to_openai_dict_format(require_tool_call_ids=True)
+
+
+def test_to_openai_dict_format_require_tool_call_ids_false():
+    tool_call_null_id = ToolCall(id=None, tool_name="weather", arguments={"city": "Paris"})
+    message = ChatMessage.from_assistant(tool_calls=[tool_call_null_id])
+    openai_msg = message.to_openai_dict_format(require_tool_call_ids=False)
+
+    assert openai_msg == {
+        "role": "assistant",
+        "tool_calls": [{"type": "function", "function": {"name": "weather", "arguments": '{"city": "Paris"}'}}],
+    }
+
+    message = ChatMessage.from_tool(tool_result="result", origin=tool_call_null_id)
+    openai_msg = message.to_openai_dict_format(require_tool_call_ids=False)
+    assert openai_msg == {"role": "tool", "content": "result"}
 
 
 def test_from_openai_dict_format_user_message():