diff --git a/tests/conftest.py b/tests/conftest.py
index 372e1500..bac107ea 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -67,6 +67,31 @@ class VerificationLogger:
    f.write(f"{status} {self.test_name} ({result_msg})\n\n")
   print(f"[FINAL] {self.test_name}: {status} - {result_msg}")
 
+@pytest.fixture(autouse=True)
+def isolate_workspace(tmp_path_factory, monkeypatch) -> Generator[None, None, None]:
+ """
+ Autouse fixture to isolate tests from the active user workspace.
+ Protects the real config.toml and manual_slop.toml from being overwritten.
+ """
+ test_workspace = tmp_path_factory.mktemp("isolated_workspace")
+ 
+ config_path = test_workspace / "config.toml"
+ import tomli_w
+ with open(config_path, "wb") as f:
+  tomli_w.dump({
+   'ai': {'provider': 'gemini', 'model': 'gemini-2.5-flash-lite'},
+   'projects': {'paths': [], 'active': ''},
+   'gui': {'show_windows': {}}
+  }, f)
+
+ monkeypatch.setenv("SLOP_CONFIG", str(config_path))
+ monkeypatch.setenv("SLOP_GLOBAL_PRESETS", str(test_workspace / "presets.toml"))
+ monkeypatch.setenv("SLOP_GLOBAL_TOOL_PRESETS", str(test_workspace / "tool_presets.toml"))
+ monkeypatch.setenv("SLOP_GLOBAL_PERSONAS", str(test_workspace / "personas.toml"))
+ monkeypatch.setenv("SLOP_GLOBAL_WORKSPACE_PROFILES", str(test_workspace / "workspace_profiles.toml"))
+ 
+ yield
+
 @pytest.fixture(autouse=True)
 def reset_paths() -> Generator[None, None, None]:
  """
diff --git a/tests/test_history_management.py b/tests/test_history_management.py
index 1357648f..ab6a957d 100644
--- a/tests/test_history_management.py
+++ b/tests/test_history_management.py
@@ -28,11 +28,10 @@ def test_aggregate_includes_segregated_history() -> None:
 def test_mcp_blacklist() -> None:
  """Tests that the MCP client correctly blacklists files"""
  from src import mcp_client
- from src.models import CONFIG_PATH
- # CONFIG_PATH is usually something like 'config.toml'
- assert mcp_client._is_allowed(Path("src/gui_2.py")) is True
+ from src import paths
  # config.toml should be blacklisted for reading by the AI
- assert mcp_client._is_allowed(Path(CONFIG_PATH)) is False
+ assert mcp_client._is_allowed(Path("src/gui_2.py")) is True
+ assert mcp_client._is_allowed(paths.get_config_path()) is False
 
 def test_aggregate_blacklist() -> None:
  """Tests that aggregate correctly excludes blacklisted files"""