diff --git a/src/app_controller.py b/src/app_controller.py
index b0836b0f..7375c50c 100644
--- a/src/app_controller.py
+++ b/src/app_controller.py
@@ -3405,8 +3405,18 @@ class AppController:
   self.active_tickets = []
   self.engines.clear()
   self.mma_streams.clear()
-  # Reset mma_tier_usage to pre-populated default (prior tests pollute it)
-  self.mma_tier_usage = {'Tier 1': {}, 'Tier 2': {}, 'Tier 3': {}, 'Tier 4': {}}
+  # Reset mma_tier_usage to the same shape as __init__ (line 952-957). Prior
+  # tests pollute it; downstream consumers like _flush_to_project require
+  # every tier entry to have 'model' / 'provider' / 'tool_preset' keys. The
+  # pre-populated defaults (input=0, output=0, provider='gemini', model=
+  # tier default, tool_preset=None) restore the contract without retaining
+  # any polluted model names or token counts from a prior session.
+  self.mma_tier_usage = {
+   "Tier 1": {"input": 0, "output": 0, "provider": "gemini", "model": "gemini-3.1-pro-preview", "tool_preset": None},
+   "Tier 2": {"input": 0, "output": 0, "provider": "gemini", "model": "gemini-3-flash-preview", "tool_preset": None},
+   "Tier 3": {"input": 0, "output": 0, "provider": "gemini", "model": "gemini-2.5-flash-lite",  "tool_preset": None},
+   "Tier 4": {"input": 0, "output": 0, "provider": "gemini", "model": "gemini-2.5-flash-lite",  "tool_preset": None},
+  }
   # Reset RAG engine state so the chroma collection from a prior test
   # doesn't leak into the next session. The next _sync_rag_engine will
   # rebuild the engine with the new active_project_root.