diff --git a/run_agent.py b/run_agent.py
index e696ded0..29f01120 100644
--- a/run_agent.py
+++ b/run_agent.py
@@ -5582,6 +5582,12 @@ class AIAgent:
                     invalid_json_args = []
                     for tc in assistant_message.tool_calls:
                         args = tc.function.arguments
+                        if isinstance(args, (dict, list)):
+                            tc.function.arguments = json.dumps(args)
+                            continue
+                        if args is not None and not isinstance(args, str):
+                            tc.function.arguments = str(args)
+                            args = tc.function.arguments
                         # Treat empty/whitespace strings as empty object
                         if not args or not args.strip():
                             tc.function.arguments = "{}"
diff --git a/tests/test_dict_tool_call_args.py b/tests/test_dict_tool_call_args.py
new file mode 100644
index 00000000..e8b4d70f
--- /dev/null
+++ b/tests/test_dict_tool_call_args.py
@@ -0,0 +1,72 @@
+import json
+from types import SimpleNamespace
+
+
+def _tool_call(name: str, arguments):
+    return SimpleNamespace(
+        id="call_1",
+        type="function",
+        function=SimpleNamespace(name=name, arguments=arguments),
+    )
+
+
+def _response_with_tool_call(arguments):
+    assistant = SimpleNamespace(
+        content=None,
+        reasoning=None,
+        tool_calls=[_tool_call("read_file", arguments)],
+    )
+    choice = SimpleNamespace(message=assistant, finish_reason="tool_calls")
+    return SimpleNamespace(choices=[choice], usage=None)
+
+
+class _FakeChatCompletions:
+    def __init__(self):
+        self.calls = 0
+
+    def create(self, **kwargs):
+        self.calls += 1
+        if self.calls == 1:
+            return _response_with_tool_call({"path": "README.md"})
+        return SimpleNamespace(
+            choices=[
+                SimpleNamespace(
+                    message=SimpleNamespace(content="done", reasoning=None, tool_calls=[]),
+                    finish_reason="stop",
+                )
+            ],
+            usage=None,
+        )
+
+
+class _FakeClient:
+    def __init__(self):
+        self.chat = SimpleNamespace(completions=_FakeChatCompletions())
+
+
+def test_tool_call_validation_accepts_dict_arguments(monkeypatch):
+    from run_agent import AIAgent
+
+    monkeypatch.setattr("run_agent.OpenAI", lambda **kwargs: _FakeClient())
+    monkeypatch.setattr(
+        "run_agent.get_tool_definitions",
+        lambda *args, **kwargs: [{"function": {"name": "read_file"}}],
+    )
+    monkeypatch.setattr(
+        "run_agent.handle_function_call",
+        lambda name, args, task_id=None, **kwargs: json.dumps({"ok": True, "args": args}),
+    )
+
+    agent = AIAgent(
+        model="test-model",
+        api_key="test-key",
+        base_url="http://localhost:8080/v1",
+        platform="cli",
+        max_iterations=3,
+        quiet_mode=True,
+        skip_memory=True,
+    )
+
+    result = agent.run_conversation("read the file")
+
+    assert result["final_response"] == "done"