diff --git a/mem0/memory/utils.py b/mem0/memory/utils.py
index 253f6b4b4..dbfd3384d 100644
--- a/mem0/memory/utils.py
+++ b/mem0/memory/utils.py
@@ -61,12 +61,18 @@ def ensure_json_instruction(system_prompt, user_prompt):
 def parse_messages(messages):
     response = ""
     for msg in messages:
-        if msg["role"] == "system":
-            response += f"system: {msg['content']}\n"
-        if msg["role"] == "user":
-            response += f"user: {msg['content']}\n"
-        if msg["role"] == "assistant":
-            response += f"assistant: {msg['content']}\n"
+        role = msg.get("role")
+        content = msg.get("content")
+        # Skip messages without textual content (e.g. assistant tool-call
+        # messages that carry `tool_calls` but no `content` key).
+        if content is None:
+            continue
+        if role == "system":
+            response += f"system: {content}\n"
+        elif role == "user":
+            response += f"user: {content}\n"
+        elif role == "assistant":
+            response += f"assistant: {content}\n"
     return response
 
 
@@ -173,12 +179,19 @@ def parse_vision_messages(messages, llm=None, vision_details="auto"):
     """
     returned_messages = []
     for msg in messages:
-        if msg["role"] == "system":
+        role = msg.get("role")
+        content = msg.get("content")
+        if role == "system":
             returned_messages.append(msg)
             continue
 
+        # Skip messages without content (e.g. assistant tool-call messages
+        # that carry `tool_calls` but no `content` key).
+        if content is None:
+            continue
+
         # Handle message content
-        if isinstance(msg["content"], list):
+        if isinstance(content, list):
             if llm is None:
                 text_parts = [
                     part["text"] for part in msg["content"]
@@ -186,17 +199,17 @@ def parse_vision_messages(messages, llm=None, vision_details="auto"):
                 ]
                 if not text_parts:
                     continue
-                returned_messages.append({"role": msg["role"], "content": " ".join(text_parts)})
+                returned_messages.append({"role": role, "content": " ".join(text_parts)})
             else:
                 description = get_image_description(msg, llm, vision_details)
-                returned_messages.append({"role": msg["role"], "content": description})
-        elif isinstance(msg["content"], dict) and msg["content"].get("type") == "image_url":
+                returned_messages.append({"role": role, "content": description})
+        elif isinstance(content, dict) and content.get("type") == "image_url":
             if llm is None:
                 continue
-            image_url = msg["content"]["image_url"]["url"]
+            image_url = content["image_url"]["url"]
             try:
                 description = get_image_description(image_url, llm, vision_details)
-                returned_messages.append({"role": msg["role"], "content": description})
+                returned_messages.append({"role": role, "content": description})
             except Exception:
                 raise Exception(f"Error while downloading {image_url}.")
         else:
diff --git a/tests/memory/test_memory_utils.py b/tests/memory/test_memory_utils.py
index 8cf39475a..820729133 100644
--- a/tests/memory/test_memory_utils.py
+++ b/tests/memory/test_memory_utils.py
@@ -1,10 +1,50 @@
 import pytest
 from unittest.mock import Mock
 
-from mem0.memory.utils import parse_vision_messages, remove_spaces_from_entities, sanitize_relationship_for_cypher
+from mem0.memory.utils import (
+    parse_messages,
+    parse_vision_messages,
+    remove_spaces_from_entities,
+    sanitize_relationship_for_cypher,
+)
+
+
+class TestParseMessages:
+    def test_skips_message_without_content_key(self):
+        # Reproduces #5067: a FunctionCalling assistant message carries
+        # `tool_calls` but no `content` key -> used to raise KeyError.
+        messages = [
+            {"role": "user", "content": "hi"},
+            {"role": "assistant", "tool_calls": [{"id": "1", "function": {"name": "search"}}]},
+            {"role": "assistant", "content": "done"},
+        ]
+        result = parse_messages(messages)
+        assert result == "user: hi\nassistant: done\n"
+
+    def test_skips_explicit_none_content(self):
+        messages = [{"role": "assistant", "content": None}, {"role": "user", "content": "ok"}]
+        assert parse_messages(messages) == "user: ok\n"
+
+    def test_plain_roles_pass_through(self):
+        messages = [
+            {"role": "system", "content": "sys"},
+            {"role": "user", "content": "u"},
+            {"role": "assistant", "content": "a"},
+        ]
+        assert parse_messages(messages) == "system: sys\nuser: u\nassistant: a\n"
 
 
 class TestParseVisionMessages:
+    def test_skips_message_without_content_key(self):
+        # Reproduces #5067 for the vision parser path.
+        messages = [
+            {"role": "user", "content": "hi"},
+            {"role": "assistant", "tool_calls": [{"id": "1", "function": {"name": "search"}}]},
+        ]
+        result = parse_vision_messages(messages, llm=None)
+        assert len(result) == 1
+        assert result[0] == {"role": "user", "content": "hi"}
+
     def test_multimodal_list_without_llm_extracts_text(self):
         messages = [
             {"role": "user", "content": [