diff --git a/project_history.toml b/project_history.toml
index fd647ec..b2928d9 100644
--- a/project_history.toml
+++ b/project_history.toml
@@ -9,5 +9,5 @@ active = "main"
 
 [discussions.main]
 git_commit = ""
-last_updated = "2026-05-02T12:45:18"
+last_updated = "2026-05-02T14:52:30"
 history = []
diff --git a/src/ai_client.py b/src/ai_client.py
index 36caf8e..3bef88f 100644
--- a/src/ai_client.py
+++ b/src/ai_client.py
@@ -182,6 +182,9 @@ def _get_combined_system_prompt(preset: Optional[ToolPreset] = None, bias: Optio
    base += f"\n\n{strategy}"
  return base
 
+def get_combined_system_prompt(preset: Optional[ToolPreset] = None, bias: Optional[BiasProfile] = None) -> str:
+ return _get_combined_system_prompt(preset, bias)
+
 from collections import deque
 
 _comms_log: deque[dict[str, Any]] = deque(maxlen=1000)
diff --git a/tests/mock_concurrent_mma.py b/tests/mock_concurrent_mma.py
new file mode 100644
index 0000000..03742fb
--- /dev/null
+++ b/tests/mock_concurrent_mma.py
@@ -0,0 +1,84 @@
+import sys
+import json
+import os
+
+def main() -> None:
+ # Read prompt from stdin
+ try:
+  prompt = sys.stdin.read()
+ except Exception:
+  prompt = ""
+ 
+ # 1. Epic Initialization
+ if 'PATH: Epic Initialization' in prompt:
+  mock_response = [
+   {"id": "track-a", "goal": "Track A Goal", "title": "Track A"},
+   {"id": "track-b", "goal": "Track B Goal", "title": "Track B"}
+  ]
+  print(json.dumps({
+   "type": "message",
+   "role": "assistant",
+   "content": json.dumps(mock_response)
+  }), flush=True)
+  print(json.dumps({
+   "type": "result",
+   "status": "success",
+   "stats": {"total_tokens": 100, "input_tokens": 50, "output_tokens": 50},
+   "session_id": "mock-epic"
+  }), flush=True)
+  return
+
+ # 2. Sprint Planning (different tickets for different tracks)
+ if 'generate the implementation tickets' in prompt:
+  track_label = "A" if "Track A" in prompt else "B"
+  mock_response = [
+   {"id": f"ticket-{track_label}-1", "description": f"Ticket {track_label} 1", "status": "todo", "assigned_to": "worker", "depends_on": []}
+  ]
+  print(json.dumps({
+   "type": "message",
+   "role": "assistant",
+   "content": json.dumps(mock_response)
+  }), flush=True)
+  print(json.dumps({
+   "type": "result",
+   "status": "success",
+   "stats": {"total_tokens": 100, "input_tokens": 50, "output_tokens": 50},
+   "session_id": f"mock-sprint-{track_label}"
+  }), flush=True)
+  return
+
+ # 3. Worker Execution
+ if 'You are assigned to Ticket' in prompt:
+  # Extract ticket ID
+  import re
+  match = re.search(r'Ticket (ticket-[A-B]-1)', prompt)
+  tid = match.group(1) if match else "unknown"
+  
+  print(json.dumps({
+   "type": "message",
+   "role": "assistant",
+   "content": f"Working on {tid}. Done."
+  }), flush=True)
+  print(json.dumps({
+   "type": "result",
+   "status": "success",
+   "stats": {"total_tokens": 50, "input_tokens": 25, "output_tokens": 25},
+   "session_id": f"mock-worker-{tid}"
+  }), flush=True)
+  return
+
+ # Default
+ print(json.dumps({
+  "type": "message",
+  "role": "assistant",
+  "content": "Mock response"
+ }), flush=True)
+ print(json.dumps({
+  "type": "result",
+  "status": "success",
+  "stats": {"total_tokens": 10, "input_tokens": 5, "output_tokens": 5},
+  "session_id": "mock-default"
+ }), flush=True)
+
+if __name__ == "__main__":
+ main()
diff --git a/tests/test_mma_concurrent_tracks_sim.py b/tests/test_mma_concurrent_tracks_sim.py
new file mode 100644
index 0000000..819ee6d
--- /dev/null
+++ b/tests/test_mma_concurrent_tracks_sim.py
@@ -0,0 +1,135 @@
+import pytest
+import time
+import sys
+import os
+
+# Ensure project root is in path
+sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), "..")))
+sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "src")))
+
+from src import api_hook_client
+
+def _poll_mma_status(client, timeout, condition, label):
+ """Poll get_mma_status() until condition(status) is True or timeout."""
+ last_status = {}
+ for i in range(timeout):
+  status = client.get_mma_status() or {}
+  if condition(status):
+   return True, status
+  last_status = status
+  time.sleep(1)
+ return False, last_status
+
+@pytest.mark.integration
+@pytest.mark.timeout(300)
+def test_mma_concurrent_tracks_execution(live_gui) -> None:
+ """
+ Stress test for concurrent MMA track execution.
+ Verifies that starting multiple tracks simultaneously doesn't cause crashes
+ and that workers from both tracks are processed.
+ """
+ client = api_hook_client.ApiHookClient()
+ assert client.wait_for_server(timeout=15), "Hook server did not start"
+
+ # 1. Setup provider to custom mock
+ mock_path = os.path.abspath("tests/mock_concurrent_mma.py")
+ client.set_value('current_provider', 'gemini_cli')
+ client.set_value('gcli_path', f'"{sys.executable}" "{mock_path}"')
+ client.click('btn_project_save')
+ time.sleep(1.0)
+
+ # 2. Plan Epic to generate tracks
+ print("[SIM] Planning Epic...")
+ client.set_value('mma_epic_input', 'PATH: Epic Initialization')
+ client.click('btn_mma_plan_epic')
+ 
+ ok, status = _poll_mma_status(client, 60, 
+  lambda s: len(s.get('proposed_tracks', [])) >= 2, "plan-epic")
+ assert ok, f"Proposed tracks not found: {status.get('proposed_tracks')}"
+ print(f"[SIM] Found {len(status['proposed_tracks'])} proposed tracks.")
+
+ # 3. Accept tracks and wait for them to be created
+ print("[SIM] Accepting tracks...")
+ client.click('btn_mma_accept_tracks')
+ ok, status = _poll_mma_status(client, 30, 
+  lambda s: len(s.get('tracks', [])) >= 2, "accept-tracks")
+ assert ok, "Tracks not created in project"
+ 
+ tracks = status.get('tracks', [])
+ track_a_id = next(t['id'] for t in tracks if 'track-a' in t['id'] or 'Track A' in t['title'])
+ track_b_id = next(t['id'] for t in tracks if 'track-b' in t['id'] or 'Track B' in t['title'])
+ print(f"[SIM] Track IDs: A={track_a_id}, B={track_b_id}")
+
+ # 4. Start BOTH tracks concurrently
+ print(f"[SIM] Starting Track A ({track_a_id})...")
+ client.click('btn_mma_start_track', user_data=track_a_id)
+ 
+ # Tiny sleep to allow the first one to initialize its engine
+ time.sleep(0.5)
+ 
+ print(f"[SIM] Starting Track B ({track_b_id})...")
+ client.click('btn_mma_start_track', user_data=track_b_id)
+
+ # 5. Verify workers from BOTH tracks appear in mma_streams
+ print("[SIM] Verifying concurrent worker activity...")
+ seen_a = False
+ seen_b = False
+ 
+ for i in range(40):
+  res = client.get_mma_workers() or {}
+  workers = res.get('workers', {})
+  stream_ids = workers.keys()
+  
+  if any("ticket-A-1" in sid for sid in stream_ids):
+   seen_a = True
+  if any("ticket-B-1" in sid for sid in stream_ids):
+   seen_b = True
+   
+  if seen_a and seen_b:
+   print(f"[SIM] SUCCESS: Observed workers from both tracks at t={i}s")
+   break
+  
+  time.sleep(1)
+  if i % 5 == 0:
+   print(f"[SIM] t={i}s: seen_a={seen_a}, seen_b={seen_b}, active_streams={list(stream_ids)}")
+
+ assert seen_a, "Worker from Track A never appeared in mma_streams"
+ assert seen_b, "Worker from Track B never appeared in mma_streams"
+
+ # 6. Wait for both tracks to complete
+ print("[SIM] Waiting for tracks to complete...")
+ # Each track has 1 ticket in our mock.
+ completed_a = False
+ completed_b = False
+ 
+ for i in range(60):
+  res = client.get_mma_workers() or {}
+  workers = res.get('workers', {})
+  
+  # Check stream content for completion marker from our mock
+  for sid, text in workers.items():
+   if "ticket-A-1" in sid:
+    if "Done." in text:
+     completed_a = True
+    else:
+     if i % 10 == 0: print(f"[SIM] t={i}s: Stream A: {text[:50]}...")
+   if "ticket-B-1" in sid:
+    if "Done." in text:
+     completed_b = True
+    else:
+     if i % 10 == 0: print(f"[SIM] t={i}s: Stream B: {text[:50]}...")
+    
+  if completed_a and completed_b:
+   print(f"[SIM] Both tracks completed at t={i}s")
+   break
+  time.sleep(1)
+
+ assert completed_a, "Track A did not complete"
+ assert completed_b, "Track B did not complete"
+ 
+ # 7. Final stability check - ensure no crashes occurred in Hook Server
+ status = client.get_mma_status()
+ assert status is not None
+ assert status.get('mma_status') in ['done', 'idle', 'running']
+ 
+ print("[SIM] Concurrent MMA tracks stress test PASSED.")
diff --git a/tests/test_mma_step_mode_sim.py b/tests/test_mma_step_mode_sim.py
index 3f52f4f..f91854c 100644
--- a/tests/test_mma_step_mode_sim.py
+++ b/tests/test_mma_step_mode_sim.py
@@ -56,12 +56,10 @@ def test_mma_step_mode_approval_flow(live_gui) -> None:
  tickets = status.get('active_tickets', [])
  tid = tickets[0]['id']
  
- # 4. Attempt to approve (THIS SHOULD FAIL OR DO NOTHING CURRENTLY)
+ # 4. Attempt to approve
  print(f"[SIM] Attempting to approve ticket {tid}...")
- # We'll try to use mutate_mma_dag to set status to in_progress
- # (Note: this uses the bugged '_mutate_dag' endpoint internally if not fixed)
- res = client.mutate_mma_dag({"ticket_id": tid, "status": "in_progress"})
- print(f"[SIM] Mutate result: {res}")
+ res = client.approve_mma_ticket(tid)
+ print(f"[SIM] Approve result: {res}")
  
  # 5. Verify it moved to in_progress
  ok, status = _poll_mma_status(client, timeout=10, label="verify-in-progress",