diff --git a/tests/conftest.py b/tests/conftest.py
index baae124..2b4bf01 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,6 +1,27 @@
 """Minimal test configuration for refactored MCP-NixOS."""
 
 
+import pytest
+@pytest.fixture(autouse=True)
+def mock_get_channels(monkeypatch):
+    """Mock get_channels function to return fixed channels for all tests."""
+    def mock_channels():
+        return {
+            "unstable": "latest-43-nixos-unstable",
+            "25.05": "latest-43-nixos-25.05",
+            "25.11": "latest-43-nixos-25.11",
+            "24.11": "latest-43-nixos-24.11",
+            "stable": "latest-43-nixos-25.05",
+            "beta": "latest-43-nixos-25.05"
+        }
+
+    # Patch the function in the server module
+    monkeypatch.setattr('mcp_nixos.server.get_channels', mock_channels)
+
+    # Also patch any imported references in test modules
+    monkeypatch.setattr('tests.test_server.get_channels', mock_channels)
+
+
 def pytest_addoption(parser):
     """Add test filtering options."""
     parser.addoption("--unit", action="store_true", help="Run unit tests only")