feat(ai_client): isolation of current_tier using threading.local() for parallel agent safety

tests/test_ai_client_concurrency.py

@@ -0,0 +1,39 @@
+import threading
+from src import ai_client
+
+def test_ai_client_tier_isolation():
+ original_append = ai_client._append_comms
+ captured_logs = []
+ def intercepted_append(direction, kind, payload):
+  captured_logs.append({
+   'thread_name': threading.current_thread().name,
+   'source_tier': ai_client.get_current_tier()
+  })
+  original_append(direction, kind, payload)
+ ai_client._append_comms = intercepted_append
+ ai_client.clear_comms_log()
+ barrier = threading.Barrier(2)
+ def run_t1():
+  ai_client.set_current_tier('Tier 3')
+  barrier.wait()
+  ai_client._append_comms('OUT', 'test', {})
+ def run_t2():
+  ai_client.set_current_tier('Tier 4')
+  barrier.wait()
+  ai_client._append_comms('OUT', 'test', {})
+ t1 = threading.Thread(target=run_t1, name='T1')
+ t2 = threading.Thread(target=run_t2, name='T2')
+ t1.start()
+ t2.start()
+ t1.join()
+ t2.join()
+ try:
+  log_t1 = next(log for log in captured_logs if log['thread_name'] == 'T1')
+  log_t2 = next(log for log in captured_logs if log['thread_name'] == 'T2')
+  assert log_t1['source_tier'] == 'Tier 3'
+  assert log_t2['source_tier'] == 'Tier 4'
+ finally:
+  ai_client._append_comms = original_append
+
+if __name__ == "__main__":
+ test_ai_client_tier_isolation()

tests/test_mma_agent_focus_phase1.py

@@ -7,15 +7,14 @@ state when logging comms and tools.
 from src import ai_client
 
 def reset_tier():
- ai_client.current_tier = None
+ ai_client.set_current_tier(None)
  yield
- ai_client.current_tier = None
+ ai_client.set_current_tier(None)
 
-def test_current_tier_variable_exists() -> None:
- """ai_client must expose a module-level current_tier variable."""
- assert hasattr(ai_client, "current_tier")
- # current_tier might be None or a default
- pass
+def test_get_current_tier_exists() -> None:
+ """ai_client must expose a get_current_tier function."""
+ assert hasattr(ai_client, "get_current_tier")
+ assert callable(ai_client.get_current_tier)
 
 def test_append_comms_has_source_tier_key() -> None:
  """Dict entries in comms log must have a 'source_tier' key."""
@@ -30,7 +29,7 @@ def test_append_comms_has_source_tier_key() -> None:
 def test_append_comms_source_tier_none_when_unset() -> None:
  """When current_tier is None, source_tier in log must be None."""
  ai_client.reset_session()
- ai_client.current_tier = None
+ ai_client.set_current_tier(None)
  ai_client._append_comms("OUT", "request", {"msg": "hello"})
  
  log = ai_client.get_comms_log()
@@ -39,22 +38,22 @@ def test_append_comms_source_tier_none_when_unset() -> None:
 def test_append_comms_source_tier_set_when_current_tier_set() -> None:
  """When current_tier is 'Tier 1', source_tier in log must be 'Tier 1'."""
  ai_client.reset_session()
- ai_client.current_tier = "Tier 1"
+ ai_client.set_current_tier("Tier 1")
  ai_client._append_comms("OUT", "request", {"msg": "hello"})
  
  log = ai_client.get_comms_log()
  assert log[-1]["source_tier"] == "Tier 1"
- ai_client.current_tier = None
+ ai_client.set_current_tier(None)
 
 def test_append_comms_source_tier_tier2() -> None:
  """When current_tier is 'Tier 2', source_tier in log must be 'Tier 2'."""
  ai_client.reset_session()
- ai_client.current_tier = "Tier 2"
+ ai_client.set_current_tier("Tier 2")
  ai_client._append_comms("OUT", "request", {"msg": "hello"})
  
  log = ai_client.get_comms_log()
  assert log[-1]["source_tier"] == "Tier 2"
- ai_client.current_tier = None
+ ai_client.set_current_tier(None)
 
 def test_append_tool_log_stores_dict(app_instance) -> None:
  """App._append_tool_log must store a dict in self._tool_log."""

tests/test_token_usage.py

@@ -9,6 +9,7 @@ from src import ai_client
 
 def test_token_usage_tracking() -> None:
  ai_client.reset_session()
+ ai_client.clear_comms_log()
  with patch("src.ai_client._ensure_gemini_client"), \
  patch("src.ai_client._gemini_client") as mock_client:
   mock_chat = MagicMock()