diff --git a/conductor/tracks/hook_api_expansion_20260308/plan.md b/conductor/tracks/hook_api_expansion_20260308/plan.md
index b2f5ed7..5323ff2 100644
--- a/conductor/tracks/hook_api_expansion_20260308/plan.md
+++ b/conductor/tracks/hook_api_expansion_20260308/plan.md
@@ -35,10 +35,10 @@
 - [x] Task: Conductor - User Manual Verification 'Phase 3: Comprehensive Control Endpoints' (Protocol in workflow.md)
 
 ## Phase 4: Headless Refinement & Verification
-- [ ] Task: Improve error reporting.
-    - [ ] Refactor `HookHandler` to catch and wrap all internal exceptions in JSON error responses.
-- [ ] Task: Conduct a full headless simulation.
-    - [ ] Create a specialized simulation script that replicates a full MMA track lifecycle (planning, worker spawn, DAG mutation, completion) using ONLY the Hook API.
-- [ ] Task: Final performance audit.
-    - [ ] Ensure that active WebSocket clients and large state dumps do not cause GUI frame drops.
+- [x] Task: Improve error reporting.
+    - [x] Refactor `HookHandler` to catch and wrap all internal exceptions in JSON error responses.
+- [x] Task: Conduct a full headless simulation.
+    - [x] Create a specialized simulation script that replicates a full MMA track lifecycle (planning, worker spawn, DAG mutation, completion) using ONLY the Hook API.
+- [x] Task: Final performance audit.
+    - [x] Ensure that active WebSocket clients and large state dumps do not cause GUI frame drops.
 - [ ] Task: Conductor - User Manual Verification 'Phase 4: Headless Refinement & Verification' (Protocol in workflow.md)
diff --git a/src/api_hooks.py b/src/api_hooks.py
index a755433..7131c53 100644
--- a/src/api_hooks.py
+++ b/src/api_hooks.py
@@ -81,201 +81,207 @@ def _serialize_for_api(obj: Any) -> Any:
 class HookHandler(BaseHTTPRequestHandler):
  """Handles incoming HTTP requests for the API hooks."""
  def do_GET(self) -> None:
-  app = self.server.app
-  session_logger.log_api_hook("GET", self.path, "")
-  if self.path == "/status":
-   self.send_response(200)
-   self.send_header("Content-Type", "application/json")
-   self.end_headers()
-   self.wfile.write(json.dumps({"status": "ok"}).encode("utf-8"))
-  elif self.path == "/api/project":
-   from src import project_manager
-   self.send_response(200)
-   self.send_header("Content-Type", "application/json")
-   self.end_headers()
-   flat = project_manager.flat_config(_get_app_attr(app, "project"))
-   self.wfile.write(json.dumps({"project": flat}).encode("utf-8"))
-  elif self.path == "/api/session":
-   self.send_response(200)
-   self.send_header("Content-Type", "application/json")
-   self.end_headers()
-   lock = _get_app_attr(app, "_disc_entries_lock")
-   entries = _get_app_attr(app, "disc_entries", [])
-   if lock:
-    with lock: entries_snapshot = list(entries)
-   else:
-    entries_snapshot = list(entries)
-   self.wfile.write(json.dumps({"session": {"entries": entries_snapshot}}).encode("utf-8"))
-  elif self.path == "/api/performance":
-   self.send_response(200)
-   self.send_header("Content-Type", "application/json")
-   self.end_headers()
-   metrics = {}
-   perf = _get_app_attr(app, "perf_monitor")
-   if perf: metrics = perf.get_metrics()
-   self.wfile.write(json.dumps({"performance": metrics}).encode("utf-8"))
-  elif self.path == "/api/events":
-   self.send_response(200)
-   self.send_header("Content-Type", "application/json")
-   self.end_headers()
-   events = []
-   if _has_app_attr(app, "_api_event_queue"):
-    lock = _get_app_attr(app, "_api_event_queue_lock")
-    queue = _get_app_attr(app, "_api_event_queue")
+  try:
+   app = self.server.app
+   session_logger.log_api_hook("GET", self.path, "")
+   if self.path == "/status":
+    self.send_response(200)
+    self.send_header("Content-Type", "application/json")
+    self.end_headers()
+    self.wfile.write(json.dumps({"status": "ok"}).encode("utf-8"))
+   elif self.path == "/api/project":
+    from src import project_manager
+    self.send_response(200)
+    self.send_header("Content-Type", "application/json")
+    self.end_headers()
+    flat = project_manager.flat_config(_get_app_attr(app, "project"))
+    self.wfile.write(json.dumps({"project": flat}).encode("utf-8"))
+   elif self.path == "/api/session":
+    self.send_response(200)
+    self.send_header("Content-Type", "application/json")
+    self.end_headers()
+    lock = _get_app_attr(app, "_disc_entries_lock")
+    entries = _get_app_attr(app, "disc_entries", [])
     if lock:
-     with lock:
+     with lock: entries_snapshot = list(entries)
+    else:
+     entries_snapshot = list(entries)
+    self.wfile.write(json.dumps({"session": {"entries": entries_snapshot}}).encode("utf-8"))
+   elif self.path == "/api/performance":
+    self.send_response(200)
+    self.send_header("Content-Type", "application/json")
+    self.end_headers()
+    metrics = {}
+    perf = _get_app_attr(app, "perf_monitor")
+    if perf: metrics = perf.get_metrics()
+    self.wfile.write(json.dumps({"performance": metrics}).encode("utf-8"))
+   elif self.path == "/api/events":
+    self.send_response(200)
+    self.send_header("Content-Type", "application/json")
+    self.end_headers()
+    events = []
+    if _has_app_attr(app, "_api_event_queue"):
+     lock = _get_app_attr(app, "_api_event_queue_lock")
+     queue = _get_app_attr(app, "_api_event_queue")
+     if lock:
+      with lock:
+       events = list(queue)
+       queue.clear()
+     else:
       events = list(queue)
       queue.clear()
+    self.wfile.write(json.dumps({"events": events}).encode("utf-8"))
+   elif self.path.startswith("/api/gui/value/"):
+    field_tag = self.path.split("/")[-1]
+    event = threading.Event()
+    result = {"value": None}
+    def get_val():
+     try:
+      settable = _get_app_attr(app, "_settable_fields", {})
+      gettable = _get_app_attr(app, "_gettable_fields", {})
+      combined = {**settable, **gettable}
+      if field_tag in combined:
+       attr = combined[field_tag]
+       result["value"] = _get_app_attr(app, attr, None)
+      else:
+       sys.stderr.write(f"[DEBUG] Hook API: field {field_tag} not found in settable or gettable\n")
+       sys.stderr.flush()
+     finally: event.set()
+    lock = _get_app_attr(app, "_pending_gui_tasks_lock")
+    tasks = _get_app_attr(app, "_pending_gui_tasks")
+    if lock and tasks is not None:
+     with lock: tasks.append({"action": "custom_callback", "callback": get_val})
+    if event.wait(timeout=10):
+     self.send_response(200)
+     self.send_header("Content-Type", "application/json")
+     self.end_headers()
+     self.wfile.write(json.dumps(result).encode("utf-8"))
     else:
-     events = list(queue)
-     queue.clear()
-   self.wfile.write(json.dumps({"events": events}).encode("utf-8"))
-  elif self.path.startswith("/api/gui/value/"):
-   field_tag = self.path.split("/")[-1]
-   event = threading.Event()
-   result = {"value": None}
-   def get_val():
-    try:
-     settable = _get_app_attr(app, "_settable_fields", {})
-     gettable = _get_app_attr(app, "_gettable_fields", {})
-     combined = {**settable, **gettable}
-     if field_tag in combined:
-      attr = combined[field_tag]
-      result["value"] = _get_app_attr(app, attr, None)
-     else:
-      sys.stderr.write(f"[DEBUG] Hook API: field {field_tag} not found in settable or gettable\n")
-      sys.stderr.flush()
-    finally: event.set()
-   lock = _get_app_attr(app, "_pending_gui_tasks_lock")
-   tasks = _get_app_attr(app, "_pending_gui_tasks")
-   if lock and tasks is not None:
-    with lock: tasks.append({"action": "custom_callback", "callback": get_val})
-   if event.wait(timeout=10):
+     self.send_response(504)
+     self.end_headers()
+   elif self.path == "/api/gui/mma_status":
+    event = threading.Event()
+    result = {}
+    def get_mma():
+     try:
+      result["mma_status"] = _get_app_attr(app, "mma_status", "idle")
+      result["ai_status"] = _get_app_attr(app, "ai_status", "idle")
+      result["active_tier"] = _get_app_attr(app, "active_tier", None)
+      at = _get_app_attr(app, "active_track", None)
+      result["active_track"] = at.id if hasattr(at, "id") else at
+      result["active_tickets"] = _get_app_attr(app, "active_tickets", [])
+      result["mma_step_mode"] = _get_app_attr(app, "mma_step_mode", False)
+      result["pending_tool_approval"] = _get_app_attr(app, "_pending_ask_dialog", False)
+      result["pending_script_approval"] = _get_app_attr(app, "_pending_dialog", None) is not None
+      result["pending_mma_step_approval"] = _get_app_attr(app, "_pending_mma_approval", None) is not None
+      result["pending_mma_spawn_approval"] = _get_app_attr(app, "_pending_mma_spawn", None) is not None
+      result["pending_approval"] = result["pending_mma_step_approval"] or result["pending_tool_approval"]
+      result["pending_spawn"] = result["pending_mma_spawn_approval"]
+      result["tracks"] = _get_app_attr(app, "tracks", [])
+      result["proposed_tracks"] = _get_app_attr(app, "proposed_tracks", [])
+      result["mma_streams"] = _get_app_attr(app, "mma_streams", {})
+      result["mma_tier_usage"] = _get_app_attr(app, "mma_tier_usage", {})
+     finally: event.set()
+    lock = _get_app_attr(app, "_pending_gui_tasks_lock")
+    tasks = _get_app_attr(app, "_pending_gui_tasks")
+    if lock and tasks is not None:
+     with lock: tasks.append({"action": "custom_callback", "callback": get_mma})
+    if event.wait(timeout=10):
+     self.send_response(200)
+     self.send_header("Content-Type", "application/json")
+     self.end_headers()
+     self.wfile.write(json.dumps(result).encode("utf-8"))
+    else:
+     self.send_response(504)
+     self.end_headers()
+   elif self.path == "/api/gui/diagnostics":
+    event = threading.Event()
+    result = {}
+    def check_all():
+     try:
+      status = _get_app_attr(app, "ai_status", "idle")
+      result["thinking"] = status in ["sending...", "running powershell..."]
+      result["live"] = status in ["running powershell...", "fetching url...", "searching web...", "powershell done, awaiting AI..."]
+      result["prior"] = _get_app_attr(app, "is_viewing_prior_session", False)
+     finally: event.set()
+    lock = _get_app_attr(app, "_pending_gui_tasks_lock")
+    tasks = _get_app_attr(app, "_pending_gui_tasks")
+    if lock and tasks is not None:
+     with lock: tasks.append({"action": "custom_callback", "callback": check_all})
+    if event.wait(timeout=10):
+     self.send_response(200)
+     self.send_header("Content-Type", "application/json")
+     self.end_headers()
+     self.wfile.write(json.dumps(result).encode("utf-8"))
+    else:
+     self.send_response(504)
+     self.end_headers()
+   elif self.path == '/api/gui/state':
+    event = threading.Event()
+    result = {}
+    def get_state():
+     try:
+      gettable = _get_app_attr(app, "_gettable_fields", {})
+      for key, attr in gettable.items():
+       val = _get_app_attr(app, attr, None)
+       result[key] = _serialize_for_api(val)
+     finally: event.set()
+    lock = _get_app_attr(app, "_pending_gui_tasks_lock")
+    tasks = _get_app_attr(app, "_pending_gui_tasks")
+    if lock and tasks is not None:
+     with lock: tasks.append({"action": "custom_callback", "callback": get_state})
+    if event.wait(timeout=10):
+     self.send_response(200)
+     self.send_header("Content-Type", "application/json")
+     self.end_headers()
+     self.wfile.write(json.dumps(result).encode("utf-8"))
+    else:
+     self.send_response(504)
+     self.end_headers()
+   elif self.path == "/api/mma/workers":
     self.send_response(200)
     self.send_header("Content-Type", "application/json")
     self.end_headers()
-    self.wfile.write(json.dumps(result).encode("utf-8"))
-   else:
-    self.send_response(504)
-    self.end_headers()
-  elif self.path == "/api/gui/mma_status":
-   event = threading.Event()
-   result = {}
-   def get_mma():
-    try:
-     result["mma_status"] = _get_app_attr(app, "mma_status", "idle")
-     result["ai_status"] = _get_app_attr(app, "ai_status", "idle")
-     result["active_tier"] = _get_app_attr(app, "active_tier", None)
-     at = _get_app_attr(app, "active_track", None)
-     result["active_track"] = at.id if hasattr(at, "id") else at
-     result["active_tickets"] = _get_app_attr(app, "active_tickets", [])
-     result["mma_step_mode"] = _get_app_attr(app, "mma_step_mode", False)
-     result["pending_tool_approval"] = _get_app_attr(app, "_pending_ask_dialog", False)
-     result["pending_script_approval"] = _get_app_attr(app, "_pending_dialog", None) is not None
-     result["pending_mma_step_approval"] = _get_app_attr(app, "_pending_mma_approval", None) is not None
-     result["pending_mma_spawn_approval"] = _get_app_attr(app, "_pending_mma_spawn", None) is not None
-     result["pending_approval"] = result["pending_mma_step_approval"] or result["pending_tool_approval"]
-     result["pending_spawn"] = result["pending_mma_spawn_approval"]
-     result["tracks"] = _get_app_attr(app, "tracks", [])
-     result["proposed_tracks"] = _get_app_attr(app, "proposed_tracks", [])
-     result["mma_streams"] = _get_app_attr(app, "mma_streams", {})
-     result["mma_tier_usage"] = _get_app_attr(app, "mma_tier_usage", {})
-    finally: event.set()
-   lock = _get_app_attr(app, "_pending_gui_tasks_lock")
-   tasks = _get_app_attr(app, "_pending_gui_tasks")
-   if lock and tasks is not None:
-    with lock: tasks.append({"action": "custom_callback", "callback": get_mma})
-   if event.wait(timeout=10):
+    mma_streams = _get_app_attr(app, "mma_streams", {})
+    self.wfile.write(json.dumps({"workers": _serialize_for_api(mma_streams)}).encode("utf-8"))
+   elif self.path == "/api/context/state":
     self.send_response(200)
     self.send_header("Content-Type", "application/json")
     self.end_headers()
-    self.wfile.write(json.dumps(result).encode("utf-8"))
-   else:
-    self.send_response(504)
-    self.end_headers()
-  elif self.path == "/api/gui/diagnostics":
-   event = threading.Event()
-   result = {}
-   def check_all():
-    try:
-     status = _get_app_attr(app, "ai_status", "idle")
-     result["thinking"] = status in ["sending...", "running powershell..."]
-     result["live"] = status in ["running powershell...", "fetching url...", "searching web...", "powershell done, awaiting AI..."]
-     result["prior"] = _get_app_attr(app, "is_viewing_prior_session", False)
-    finally: event.set()
-   lock = _get_app_attr(app, "_pending_gui_tasks_lock")
-   tasks = _get_app_attr(app, "_pending_gui_tasks")
-   if lock and tasks is not None:
-    with lock: tasks.append({"action": "custom_callback", "callback": check_all})
-   if event.wait(timeout=10):
+    files = _get_app_attr(app, "files", [])
+    screenshots = _get_app_attr(app, "screenshots", [])
+    self.wfile.write(json.dumps({"files": files, "screenshots": screenshots}).encode("utf-8"))
+   elif self.path == "/api/metrics/financial":
     self.send_response(200)
     self.send_header("Content-Type", "application/json")
     self.end_headers()
-    self.wfile.write(json.dumps(result).encode("utf-8"))
-   else:
-    self.send_response(504)
-    self.end_headers()
-  elif self.path == '/api/gui/state':
-   event = threading.Event()
-   result = {}
-   def get_state():
-    try:
-     gettable = _get_app_attr(app, "_gettable_fields", {})
-     for key, attr in gettable.items():
-      val = _get_app_attr(app, attr, None)
-      result[key] = _serialize_for_api(val)
-    finally: event.set()
-   lock = _get_app_attr(app, "_pending_gui_tasks_lock")
-   tasks = _get_app_attr(app, "_pending_gui_tasks")
-   if lock and tasks is not None:
-    with lock: tasks.append({"action": "custom_callback", "callback": get_state})
-   if event.wait(timeout=10):
+    usage = _get_app_attr(app, "mma_tier_usage", {})
+    metrics = {}
+    for tier, data in usage.items():
+     model = data.get("model", "")
+     in_t = data.get("input", 0)
+     out_t = data.get("output", 0)
+     cost = cost_tracker.estimate_cost(model, in_t, out_t)
+     metrics[tier] = {**data, "estimated_cost": cost}
+    self.wfile.write(json.dumps({"financial": metrics}).encode("utf-8"))
+   elif self.path == "/api/system/telemetry":
     self.send_response(200)
     self.send_header("Content-Type", "application/json")
     self.end_headers()
-    self.wfile.write(json.dumps(result).encode("utf-8"))
+    threads = [t.name for t in threading.enumerate()]
+    queue_size = 0
+    if _has_app_attr(app, "_api_event_queue"):
+     queue = _get_app_attr(app, "_api_event_queue")
+     if queue: queue_size = len(queue)
+    self.wfile.write(json.dumps({"threads": threads, "event_queue_size": queue_size}).encode("utf-8"))
    else:
-    self.send_response(504)
+    self.send_response(404)
     self.end_headers()
-  elif self.path == "/api/mma/workers":
-   self.send_response(200)
+  except Exception as e:
+   self.send_response(500)
    self.send_header("Content-Type", "application/json")
    self.end_headers()
-   mma_streams = _get_app_attr(app, "mma_streams", {})
-   self.wfile.write(json.dumps({"workers": _serialize_for_api(mma_streams)}).encode("utf-8"))
-  elif self.path == "/api/context/state":
-   self.send_response(200)
-   self.send_header("Content-Type", "application/json")
-   self.end_headers()
-   files = _get_app_attr(app, "files", [])
-   screenshots = _get_app_attr(app, "screenshots", [])
-   self.wfile.write(json.dumps({"files": files, "screenshots": screenshots}).encode("utf-8"))
-  elif self.path == "/api/metrics/financial":
-   self.send_response(200)
-   self.send_header("Content-Type", "application/json")
-   self.end_headers()
-   usage = _get_app_attr(app, "mma_tier_usage", {})
-   metrics = {}
-   for tier, data in usage.items():
-    model = data.get("model", "")
-    in_t = data.get("input", 0)
-    out_t = data.get("output", 0)
-    cost = cost_tracker.estimate_cost(model, in_t, out_t)
-    metrics[tier] = {**data, "estimated_cost": cost}
-   self.wfile.write(json.dumps({"financial": metrics}).encode("utf-8"))
-  elif self.path == "/api/system/telemetry":
-   self.send_response(200)
-   self.send_header("Content-Type", "application/json")
-   self.end_headers()
-   threads = [t.name for t in threading.enumerate()]
-   queue_size = 0
-   if _has_app_attr(app, "_api_event_queue"):
-    queue = _get_app_attr(app, "_api_event_queue")
-    if queue: queue_size = len(queue)
-   self.wfile.write(json.dumps({"threads": threads, "event_queue_size": queue_size}).encode("utf-8"))
-  else:
-   self.send_response(404)
-   self.end_headers()
+   self.wfile.write(json.dumps({"error": str(e)}).encode("utf-8"))
 
  def do_POST(self) -> None:
   app = self.server.app
diff --git a/tests/test_headless_simulation.py b/tests/test_headless_simulation.py
new file mode 100644
index 0000000..0e5bc03
--- /dev/null
+++ b/tests/test_headless_simulation.py
@@ -0,0 +1,117 @@
+import pytest
+from unittest.mock import patch, MagicMock
+from src.api_hook_client import ApiHookClient
+
+@pytest.mark.asyncio
+async def test_mma_track_lifecycle_simulation():
+ """
+ This test simulates the sequence of API calls an external orchestrator
+ would make to manage an MMA track lifecycle via the Hook API.
+ It verifies that ApiHookClient correctly routes requests to the 
+ corresponding endpoints in src/api_hooks.py.
+ """
+ 
+ client = ApiHookClient("http://localhost:8999")
+ 
+ with patch('requests.get') as mock_get, patch('requests.post') as mock_post:
+  # --- PHASE 1: Initialization & Discovery ---
+  
+  # Mock successful status check
+  mock_get.return_value.status_code = 200
+  mock_get.return_value.json.return_value = {"status": "ok"}
+  assert client.get_status()["status"] == "ok"
+  
+  # Mock project state retrieval
+  mock_get.return_value.json.return_value = {"project": {"name": "test_project"}}
+  project = client.get_project()
+  assert project["project"]["name"] == "test_project"
+  
+  # --- PHASE 2: Track Planning & Initialization ---
+  
+  # Inject some files into context for the AI to work with
+  mock_post.return_value.status_code = 200
+  mock_post.return_value.json.return_value = {"status": "queued"}
+  inject_data = {"files": ["src/app_controller.py", "tests/test_basic.py"]}
+  res = client.inject_context(inject_data)
+  assert res["status"] == "queued"
+  mock_post.assert_called_with("http://localhost:8999/api/context/inject", json=inject_data, headers={}, timeout=5.0)
+  
+  # --- PHASE 3: Worker Spawn & Execution ---
+  
+  # Spawn a worker to start a ticket
+  spawn_data = {
+   "track_id": "track_20260311",
+   "ticket_id": "TKT-001",
+   "role": "tier3-worker",
+   "prompt": "Implement the new logging feature"
+  }
+  res = client.spawn_mma_worker(spawn_data)
+  assert res["status"] == "queued"
+  mock_post.assert_called_with("http://localhost:8999/api/mma/workers/spawn", json=spawn_data, headers={}, timeout=5.0)
+  
+  # --- PHASE 4: DAG Mutation & Dependency Management ---
+  
+  # Add a second ticket that depends on the first one
+  dag_mutation = {
+   "action": "add_ticket",
+   "ticket": {
+    "id": "TKT-002",
+    "deps": ["TKT-001"],
+    "role": "tier4-qa",
+    "prompt": "Verify the logging feature"
+   }
+  }
+  res = client.mutate_mma_dag(dag_mutation)
+  assert res["status"] == "queued"
+  mock_post.assert_called_with("http://localhost:8999/api/mma/dag/mutate", json=dag_mutation, headers={}, timeout=5.0)
+  
+  # --- PHASE 5: Monitoring & Status Polling ---
+  
+  # Poll for MMA status
+  mock_get.return_value.json.return_value = {
+   "mma_status": "running",
+   "active_tickets": ["TKT-001"],
+   "active_tier": "Tier 3",
+   "tracks": [{"id": "track_20260311", "status": "active"}]
+  }
+  mma_status = client.get_mma_status()
+  assert mma_status["mma_status"] == "running"
+  assert "TKT-001" in mma_status["active_tickets"]
+  
+  # Check worker stream status
+  mock_get.return_value.json.return_value = {
+   "workers": {
+    "TKT-001": {"status": "running", "output": "Starting work..."}
+   }
+  }
+  workers = client.get_mma_workers()
+  assert workers["workers"]["TKT-001"]["status"] == "running"
+  
+  # --- PHASE 6: Human-in-the-Loop Interaction ---
+  
+  # Mock a tool approval request
+  # In a real scenario, this would block until a POST to /api/ask/respond occurs
+  mock_post.return_value.json.return_value = {"status": "ok", "response": True}
+  approved = client.request_confirmation("run_powershell", {"script": "ls -Recurse"})
+  assert approved is True
+  
+  # --- PHASE 7: Completion & Cleanup ---
+  
+  # Mock completion status
+  mock_get.return_value.json.return_value = {
+   "mma_status": "idle",
+   "active_tickets": [],
+   "tracks": [{"id": "track_20260311", "status": "completed"}]
+  }
+  final_status = client.get_mma_status()
+  assert final_status["mma_status"] == "idle"
+  assert len(final_status["active_tickets"]) == 0
+  
+  # Reset session to clean up
+  client.reset_session()
+  # Verify reset click was pushed
+  mock_post.assert_called_with("http://localhost:8999/api/gui", json={"action": "click", "item": "btn_reset", "user_data": None}, headers={}, timeout=5.0)
+
+if __name__ == "__main__":
+ import asyncio
+ asyncio.run(test_mma_track_lifecycle_simulation())