diff --git a/autogen/oai/anthropic.py b/autogen/oai/anthropic.py
index 9faa4e2cb808..e2448929e618 100644
--- a/autogen/oai/anthropic.py
+++ b/autogen/oai/anthropic.py
@@ -49,10 +49,10 @@
     "claude-3-5-sonnet-20240620": (0.003, 0.015),
     "claude-3-sonnet-20240229": (0.003, 0.015),
     "claude-3-opus-20240229": (0.015, 0.075),
-    "claude-2.0": (0.008, 0.024),
+    "claude-3-haiku-20240307": (0.00025, 0.00125),
     "claude-2.1": (0.008, 0.024),
-    "claude-3.0-opus": (0.015, 0.075),
-    "claude-3.0-haiku": (0.00025, 0.00125),
+    "claude-2.0": (0.008, 0.024),
+    "claude-instant-1.2": (0.008, 0.024),
 }
 
 
@@ -250,6 +250,7 @@ def oai_messages_to_anthropic_messages(params: Dict[str, Any]) -> list[dict[str,
     tool_use_messages = 0
     tool_result_messages = 0
     last_tool_use_index = -1
+    last_tool_result_index = -1
     for message in params["messages"]:
         if message["role"] == "system":
             params["system"] = message["content"]
@@ -290,25 +291,26 @@ def oai_messages_to_anthropic_messages(params: Dict[str, Any]) -> list[dict[str,
                         }
                     )
             elif "tool_call_id" in message:
-
-                if expected_role == "assistant":
-                    # Insert an extra assistant message as we will append a user message
-                    processed_messages.append(assistant_continue_message)
-
                 if has_tools:
                     # Map the tool usage call to tool_result for Anthropic
-                    processed_messages.append(
-                        {
-                            "role": "user",
-                            "content": [
-                                {
-                                    "type": "tool_result",
-                                    "tool_use_id": message["tool_call_id"],
-                                    "content": message["content"],
-                                }
-                            ],
-                        }
-                    )
+                    tool_result = {
+                        "type": "tool_result",
+                        "tool_use_id": message["tool_call_id"],
+                        "content": message["content"],
+                    }
+
+                    # If the previous message also had a tool_result, add it to that
+                    # Otherwise append a new message
+                    if last_tool_result_index == len(processed_messages) - 1:
+                        processed_messages[-1]["content"].append(tool_result)
+                    else:
+                        if expected_role == "assistant":
+                            # Insert an extra assistant message as we will append a user message
+                            processed_messages.append(assistant_continue_message)
+
+                        processed_messages.append({"role": "user", "content": [tool_result]})
+                        last_tool_result_index = len(processed_messages) - 1
+
                     tool_result_messages += 1
                 else:
                     # Not using tools, so put in a plain text message