diff --git a/tests/test_system_prompt_sim.py b/tests/test_system_prompt_sim.py
new file mode 100644
index 0000000..5a734b9
--- /dev/null
+++ b/tests/test_system_prompt_sim.py
@@ -0,0 +1,61 @@
+import pytest
+import time
+import os
+import sys
+
+# Ensure project root is in path for imports
+sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), "..")))
+
+from src.api_hook_client import ApiHookClient
+from src import ai_client
+
+def test_system_prompt_sim(live_gui):
+ """
+ Simulation test for system prompt settings.
+ 1. Wait for server.
+ 2. Verify initial state.
+ 3. Modify settings via API.
+ 4. Verify updates.
+ 5. Use 'Reset to Default' button via API.
+ 6. Verify restoration to default text.
+ """
+ _, gui_script = live_gui
+ client = ApiHookClient()
+ 
+ # 1. Use client.wait_for_server().
+ assert client.wait_for_server(timeout=15), "Server failed to start in time"
+ 
+ # Wait a bit for GUI to settle
+ time.sleep(2)
+ 
+ # 2. Verify initial state: get_value('use_default_base_prompt') should be True.
+ initial_default = client.get_value('use_default_base_prompt')
+ assert initial_default is True, f"Expected use_default_base_prompt to be True, got {initial_default}"
+ 
+ # 3. Call client.set_value('use_default_base_prompt', False).
+ client.set_value('use_default_base_prompt', False)
+ 
+ # 4. Call client.set_value('base_system_prompt', 'Simulation Base Prompt').
+ client.set_value('base_system_prompt', 'Simulation Base Prompt')
+ 
+ # Wait for processing
+ time.sleep(0.5)
+ 
+ # 5. Verify the values were updated.
+ assert client.get_value('use_default_base_prompt') is False
+ assert client.get_value('base_system_prompt') == 'Simulation Base Prompt'
+ 
+ # 7. In the test, call client.click('btn_reset_base_prompt')
+ client.click('btn_reset_base_prompt')
+ 
+ # Give it a moment to process the click
+ time.sleep(1.0)
+ 
+ # verify use_default_base_prompt becomes False (Reset to Default sets it to False but copies the text)
+ # Wait, if it was already False, it stays False.
+ assert client.get_value('use_default_base_prompt') is False
+ 
+ # 8. Verify the effective state is correct.
+ # It should be back to ai_client._SYSTEM_PROMPT
+ current_prompt = client.get_value('base_system_prompt')
+ assert current_prompt == ai_client._SYSTEM_PROMPT, f"Prompt not reset. Got: {current_prompt[:50]}..."