fix(mma): Assign dedicated models per tier in execute_agent

tests/test_mma_exec.py

@@ -1,6 +1,6 @@
 import pytest
 from unittest.mock import patch, MagicMock
-from scripts.mma_exec import create_parser, get_role_documents, execute_agent
+from scripts.mma_exec import create_parser, get_role_documents, execute_agent, get_model_for_role
 
 def test_parser_role_choices():
     """Test that the parser accepts valid roles and the prompt argument."""
@@ -39,16 +39,24 @@ def test_get_role_documents():
     assert get_role_documents('tier3') == ['conductor/workflow.md']
     assert get_role_documents('tier4') == []
 
+def test_get_model_for_role():
+    """Test that get_model_for_role returns the correct model for each role."""
+    assert get_model_for_role('tier1-orchestrator') == 'gemini-3.1-pro-preview'
+    assert get_model_for_role('tier2-tech-lead') == 'gemini-3.0-flash-preview'
+    assert get_model_for_role('tier3-worker') == 'gemini-2.5-flash-lite'
+    assert get_model_for_role('tier4-qa') == 'gemini-2.5-flash-lite'
+
 def test_execute_agent():
     """
     Test that execute_agent calls subprocess.run with the correct gemini CLI arguments
-    for context amnesia.
+    including the model specified for the role.
     """
-    role = "tier3"
+    role = "tier3-worker"
     prompt = "Write a unit test."
     docs = ["file1.py", "docs/spec.md"]
     
-    expected_gemini_arg = "Activate the mma-tier3 skill. Write a unit test. @file1.py @docs/spec.md"
+    expected_gemini_arg = "Activate the mma-tier3-worker skill. Write a unit test. @file1.py @docs/spec.md"
+    expected_model = "gemini-2.5-flash-lite"
     mock_stdout = "Mocked AI Response"
 
     with patch("subprocess.run") as mock_run:
@@ -66,7 +74,13 @@ def test_execute_agent():
         assert cmd_list[0] == "gemini"
         assert cmd_list[1] == "-p"
         assert cmd_list[2] == expected_gemini_arg
+
+        # Verify the correct model is passed via --model flag
+        assert "--model" in cmd_list
+        model_idx = cmd_list.index("--model")
+        assert cmd_list[model_idx + 1] == expected_model
+
         assert kwargs.get("capture_output") is True
         assert kwargs.get("text") is True
-        
+
         assert result == mock_stdout