diff --git a/conductor/code_styleguides/config_state_owner.md b/conductor/code_styleguides/config_state_owner.md
new file mode 100644
index 00000000..72fa7b9a
--- /dev/null
+++ b/conductor/code_styleguides/config_state_owner.md
@@ -0,0 +1,106 @@
+# Config I/O State Ownership
+
+**Rule:** The `AppController` is the single source of truth for the
+in-memory config (`self.config`) and the only authorized caller of
+the file I/O primitives in `src/models.py`.
+
+## Why
+
+1. **The controller owns the in-memory state.** If other modules
+   write to `config.toml` directly, the controller's `self.config`
+   silently drifts from disk. Tests can corrupt the user's TOML
+   files; users lose data without warning.
+2. **Test isolation breaks.** When `models.save_config(...)` is
+   called from anywhere in `src/`, tests cannot intercept the
+   write without patching the I/O primitive. The test then
+   couples to the file format, not the controller's behavior.
+3. **Path resolution can't be enforced.** The controller respects
+   `SLOP_CONFIG` env var at call time. Direct calls to
+   `models.save_config` would only respect it if the path is
+   re-resolved (which it is in `_save_config_to_disk`, but only
+   because someone remembered).
+
+## What is Forbidden in `src/`
+
+- `models.load_config(...)` (legacy public function)
+- `models.save_config(...)` (legacy public function)
+- `models._load_config_from_disk(...)` (private I/O primitive)
+- `models._save_config_to_disk(...)` (private I/O primitive)
+
+The only allowed call sites are inside `AppController` itself
+(`load_config()` and `save_config()` methods).
+
+## The Public API
+
+```python
+# In AppController:
+def load_config(self) -> Dict[str, Any]:
+    """Re-read the global config.toml from disk and update self.config."""
+    self.config = models._load_config_from_disk()
+    return self.config
+
+def save_config(self) -> None:
+    """Flush self.config to disk."""
+    models._save_config_to_disk(self.config)
+```
+
+Callers (including `gui_2.py`, `commands.py`, etc.) go through
+the controller:
+
+```python
+# In App class methods (gui_2.py): __getattr__ delegates to controller
+self.save_config()      # -> controller.save_config()
+app.save_config()       # -> controller.save_config() (via __getattr__)
+app.load_config()       # -> controller.load_config() (via __getattr__)
+
+# In AppController:
+self.save_config()      # direct
+self.load_config()      # direct
+```
+
+## Test Patterns
+
+Tests should mock the **controller methods**, not the I/O primitives:
+
+```python
+# CORRECT: route through the controller
+with patch('src.app_controller.AppController.load_config',
+           return_value={'ai': {...}, 'projects': {...}}):
+    app = App()  # controller's load_config returns the mock
+
+with patch('src.app_controller.AppController.save_config'):
+    app._save_paths()  # controller's save_config is a no-op
+    app.save_config.assert_called_once()  # verify the call
+
+# WRONG: patch the I/O primitive
+with patch('src.models._save_config_to_disk'):  # bypasses the controller
+    app._save_paths()  # still hits the I/O primitive if production bypasses
+```
+
+The `mock_app` and `app_instance` fixtures in `tests/conftest.py`
+follow the correct pattern: they patch
+`AppController.load_config` and `AppController.save_config` to
+prevent real I/O and to provide a default config.
+
+## Exceptions
+
+The only allowed non-controller call site is the
+`test_models_no_top_level_tomli_w.py` test, which specifically
+verifies the lazy-load behavior of the I/O primitive itself
+(tomli_w import timing). This test is exempt from the audit.
+
+## Enforcement
+
+The `scripts/audit_no_models_config_io.py` script enforces this rule.
+
+- `python scripts/audit_no_models_config_io.py` — human report
+- `python scripts/audit_no_models_config_io.py --strict` — exit 1 on violation
+- `python scripts/audit_no_models_config_io.py --json` — machine output
+
+CI should run the `--strict` mode on every PR.
+
+## See Also
+
+- `docs/guide_app_controller.md` — the AppController's role
+- `docs/guide_models.md` — the models module
+- `conductor/product.md` — "Modular Controller Pattern" principle
diff --git a/conductor/product-guidelines.md b/conductor/product-guidelines.md
index 4fb8d70b..02d689c0 100644
--- a/conductor/product-guidelines.md
+++ b/conductor/product-guidelines.md
@@ -56,3 +56,4 @@ The product guidelines are best understood alongside the per-source-file guides
 - **[docs/guide_multi_agent_conductor.md](../docs/guide_multi_agent_conductor.md):** §"Thread Safety" — `threading.local()` source tier tagging, lock-protected event queue.
 - **[docs/guide_models.md](../docs/guide_models.md):** §"Design Principles" + §"SDM Tags" — centralized registry, pydantic validation, `[C: ...]` / `[M: ...]` tags in docstrings.
 - **[docs/guide_testing.md](../docs/guide_testing.md):** §"Structural Testing Contract" — Ban on Arbitrary Core Mocking, `live_gui` Standard, Artifact Isolation.
+- **[code_styleguides/config_state_owner.md](code_styleguides/config_state_owner.md):** Config I/O state ownership — `AppController` is the single source of truth; direct calls to `models.save_config`/`models.load_config` in `src/` are forbidden (enforced by `scripts/audit_no_models_config_io.py`).
diff --git a/scripts/audit_no_models_config_io.py b/scripts/audit_no_models_config_io.py
new file mode 100644
index 00000000..a931997a
--- /dev/null
+++ b/scripts/audit_no_models_config_io.py
@@ -0,0 +1,166 @@
+"""Audit script: ensure no production code in src/ calls the models I/O primitives directly.
+
+Architecture rule: AppController owns the config I/O. The
+models._load_config_from_disk and models._save_config_to_disk
+functions are private file I/O primitives. Direct callers in src/
+are an architectural smell (bypassing the controller state owner).
+
+The only allowed call sites are inside AppController itself.
+
+Usage:
+    python scripts/audit_no_models_config_io.py            # human-readable report
+    python scripts/audit_no_models_config_io.py --json     # JSON output for CI
+    python scripts/audit_no_models_config_io.py --strict   # exit 1 on violations
+"""
+from __future__ import annotations
+import argparse
+import json
+import os
+import re
+import sys
+from pathlib import Path
+
+# Patterns that are architectural smells in production code.
+# These are the I/O primitives; only AppController should call them.
+FORBIDDEN_PATTERNS = [
+    (re.compile(r"\bmodels\._load_config_from_disk\s*\("), "models._load_config_from_disk"),
+    (re.compile(r"\bmodels\._save_config_to_disk\s*\("), "models._save_config_to_disk"),
+]
+
+# The OLD public names. After the rename these should not exist anywhere.
+LEGACY_NAMES = [
+    (re.compile(r"\bmodels\.load_config\s*\("), "models.load_config"),
+    (re.compile(r"\bmodels\.save_config\s*\("), "models.save_config"),
+]
+
+# Files where these calls are LEGITIMATE.
+ALLOWED_FILES = {
+    "src/app_controller.py",   # the only public owner of the I/O
+    "src/models.py",           # the module that defines them
+    "tests/test_models_no_top_level_tomli_w.py",  # tests lazy-load behavior
+}
+
+# Source roots to scan
+SOURCE_ROOTS = ["src"]
+
+
+def find_violations() -> list[dict[str, object]]:
+    """Scan src/ for direct calls to the forbidden config I/O primitives."""
+    violations: list[dict[str, object]] = []
+    for root in SOURCE_ROOTS:
+        if not os.path.isdir(root):
+            continue
+        for dirpath, _dirs, files in os.walk(root):
+            for fname in files:
+                if not fname.endswith(".py"):
+                    continue
+                path = os.path.join(dirpath, fname)
+                # Normalize to forward slashes for matching
+                norm = path.replace(os.sep, "/")
+                if norm in ALLOWED_FILES:
+                    continue
+                with open(path, encoding="utf-8", errors="replace") as f:
+                    src = f.read()
+                docstring_lines = _docstring_lines(src)
+                for lineno, line in enumerate(src.splitlines(), start=1):
+                    if lineno in docstring_lines:
+                        continue
+                    stripped = line.lstrip()
+                    if stripped.startswith("#"):
+                        continue
+                    for pattern, name in FORBIDDEN_PATTERNS:
+                        if pattern.search(line):
+                            violations.append({
+                                "file": path,
+                                "line": lineno,
+                                "pattern": name,
+                                "text": line.rstrip(),
+                                "severity": "error",
+                            })
+                    for pattern, name in LEGACY_NAMES:
+                        if pattern.search(line):
+                            violations.append({
+                                "file": path,
+                                "line": lineno,
+                                "pattern": name,
+                                "text": line.rstrip(),
+                                "severity": "error",
+                            })
+    return violations
+
+
+def _docstring_lines(src: str) -> set[int]:
+    """Return a set of 1-based line numbers that are inside a docstring.
+
+    Uses the AST to find module/class/function docstrings, then expands
+    the string node's line range. Multi-line strings are included in
+    full so any code-looking text inside them is ignored.
+    """
+    import ast
+    lines: set[int] = set()
+    try:
+        tree = ast.parse(src)
+    except SyntaxError:
+        return lines
+    for node in ast.walk(tree):
+        if not isinstance(node, (ast.Module, ast.FunctionDef, ast.AsyncFunctionDef,
+                                 ast.ClassDef)):
+            continue
+        doc = ast.get_docstring(node, clean=False)
+        if not doc or not node.body:
+            continue
+        first = node.body[0]
+        if not isinstance(first, ast.Expr) or not isinstance(first.value, ast.Constant):
+            continue
+        if not isinstance(first.value.value, str):
+            continue
+        start = first.lineno
+        end = getattr(first, "end_lineno", None) or start
+        for ln in range(start, end + 1):
+            lines.add(ln)
+    return lines
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(
+        description="Audit for direct calls to models config I/O primitives in src/"
+    )
+    parser.add_argument("--json", action="store_true", help="JSON output for CI")
+    parser.add_argument("--strict", action="store_true", help="Exit 1 on any violation")
+    args = parser.parse_args()
+
+    violations = find_violations()
+
+    if args.json:
+        print(json.dumps({"violations": violations, "count": len(violations)}, indent=2))
+    else:
+        print("=" * 70)
+        print("Architectural audit: models config I/O usage in src/")
+        print("=" * 70)
+        print()
+        print("Rule: AppController owns config I/O. Direct calls to")
+        print("  - models._load_config_from_disk(...)")
+        print("  - models._save_config_to_disk(...)")
+        print("  - models.load_config(...)  (legacy)")
+        print("  - models.save_config(...)  (legacy)")
+        print("from outside AppController are architectural smells.")
+        print()
+        print(f"Allowed call sites: {sorted(ALLOWED_FILES)}")
+        print()
+        if not violations:
+            print("OK - no violations found.")
+        else:
+            print(f"Found {len(violations)} violation(s):")
+            print()
+            for v in violations:
+                print(f"  {v['file']}:{v['line']}: {v['pattern']}")
+                print(f"    {v['text']}")
+                print()
+
+    if args.strict and violations:
+        return 1
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/src/app_controller.py b/src/app_controller.py
index 0df96230..7992df0d 100644
--- a/src/app_controller.py
+++ b/src/app_controller.py
@@ -1707,7 +1707,7 @@ class AppController:
   self.ui_separate_response_panel   = False
   self.ui_separate_tool_calls_panel = False
   self.ui_separate_external_tools   = False
-  self.config = models.load_config()
+  self.config = self.load_config()
   theme.load_from_config(self.config)
   ai_cfg = self.config.get("ai", {})
   self._current_provider   = ai_cfg.get("provider", "gemini")
@@ -2685,7 +2685,7 @@ class AppController:
  def _cb_project_save(self) -> None:
   self._flush_to_project()
   self._flush_to_config()
-  models.save_config(self.config)
+  self.save_config()
   self.ai_status = "config saved"
 
  def _do_project_switch(self, path: str) -> None:
@@ -3360,7 +3360,7 @@ class AppController:
   """
   self._flush_to_project()
   self._flush_to_config()
-  models.save_config(self.config)
+  self.save_config()
   track_id = self.active_track.id if self.active_track else None
   flat = project_manager.flat_config(self.project, self.active_discussion, track_id=track_id)
   
@@ -3997,7 +3997,9 @@ class AppController:
    if self.active_track and self.active_track.id == track_id:
    # Use the active track object directly to start execution
     self.mma_status = "running"
-    engine = multi_agent_conductor.ConductorEngine(self.active_track, self.event_queue, auto_queue=not self.mma_step_mode)
+    _mma_cfg = self.config.get("mma", {})
+    _max_workers = int(_mma_cfg.get("max_workers", 4))
+    engine = multi_agent_conductor.ConductorEngine(self.active_track, self.event_queue, auto_queue=not self.mma_step_mode, max_workers=_max_workers)
     self.engines[self.active_track.id] = engine
     flat = project_manager.flat_config(self.project, self.active_discussion, track_id=self.active_track.id)
     full_md, _, _ = aggregate.run(flat)
@@ -4008,7 +4010,9 @@ class AppController:
     self._cb_load_track(track_id)
     if self.active_track and self.active_track.id == track_id:
      self.mma_status = "running"
-     engine = multi_agent_conductor.ConductorEngine(self.active_track, self.event_queue, auto_queue=not self.mma_step_mode)
+     _mma_cfg = self.config.get("mma", {})
+     _max_workers = int(_mma_cfg.get("max_workers", 4))
+     engine = multi_agent_conductor.ConductorEngine(self.active_track, self.event_queue, auto_queue=not self.mma_step_mode, max_workers=_max_workers)
      self.engines[self.active_track.id] = engine
      flat = project_manager.flat_config(self.project, self.active_discussion, track_id=self.active_track.id)
      full_md, _, _ = aggregate.run(flat)
@@ -4084,7 +4088,9 @@ class AppController:
    # 4. Initialize ConductorEngine and run loop
    sys.stderr.write(f"[DEBUG] _start_track_logic: Initializing engine for {track_id}...\n")
    sys.stderr.flush()
-   engine = multi_agent_conductor.ConductorEngine(track, self.event_queue, auto_queue=not self.mma_step_mode)
+   _mma_cfg = self.config.get("mma", {})
+   _max_workers = int(_mma_cfg.get("max_workers", 4))
+   engine = multi_agent_conductor.ConductorEngine(track, self.event_queue, auto_queue=not self.mma_step_mode, max_workers=_max_workers)
    self.engines[track.id] = engine
    # Use current full markdown context for the track execution
    track_id_param = track.id
@@ -4369,6 +4375,32 @@ class AppController:
     except Exception as e:
      print(f"Error loading beads: {e}")
 
+ #region: --- Config I/O (single source of truth) ---
+ def load_config(self) -> Dict[str, Any]:
+  """
+  Re-read the global config.toml from disk and update self.config.
+  Returns the dict (also stored in self.config). Single source of
+  truth for the in-memory config is self.config. Direct callers
+  from outside the controller (e.g. models.load_config) are an
+  architectural smell and will be flagged by
+  scripts/audit_no_models_config_io.py.
+  [C: src/app_controller.py:AppController.__init__]
+  """
+  self.config = models._load_config_from_disk()
+  return self.config
+
+ def save_config(self) -> None:
+  """
+  Flush self.config to disk. Single source of truth = self.config.
+  This method owns the write path. Direct callers from outside the
+  controller (e.g. models.save_config) are an architectural smell
+  and will be flagged by
+  scripts/audit_no_models_config_io.py.
+  [C: src/app_controller.py:AppController._cb_project_save, src/app_controller.py:AppController._do_generate]
+  """
+  models._save_config_to_disk(self.config)
+ #endregion: --- Config I/O (single source of truth) ---
+
  #endregion: MMA (Controller)
 
 #region: MMA
diff --git a/src/commands.py b/src/commands.py
index 6c4c4b55..f2ba893d 100644
--- a/src/commands.py
+++ b/src/commands.py
@@ -143,7 +143,7 @@ def save_all(app: "App") -> None:
  if hasattr(app, "_flush_to_config"):  app._flush_to_config()
  if hasattr(app, "config"):
   try:
-   models.save_config(app.config)
+   app.save_config()
   except Exception as e:
    if hasattr(app, "ai_status"):
     app.ai_status = f"save error: {e}"
diff --git a/src/external_editor.py b/src/external_editor.py
index 2ad28f77..d1a3ee17 100644
--- a/src/external_editor.py
+++ b/src/external_editor.py
@@ -7,7 +7,7 @@ import tempfile
 
 # TODO(Ed): Eliminate these?
 from pathlib import Path
-from typing  import Optional, List
+from typing  import Optional, List, Dict, Any
 
 from src.models import ExternalEditorConfig, TextEditorConfig
 
@@ -113,14 +113,16 @@ def auto_detect_vscode() -> Optional[TextEditorConfig]:
  return _cached_vscode_config
 
 
-def get_default_launcher() -> ExternalEditorLauncher:
+def get_default_launcher(config: Optional[Dict[str, Any]] = None) -> ExternalEditorLauncher:
  """
+ Caller passes the live config dict (typically app.config from the
+ AppController). Direct file I/O (the legacy public functions on src.models) is an
+ architectural smell (bypasses the controller state owner) and is
+ forbidden by scripts/audit_no_models_config_io.py.
  [C: src/gui_2.py:App._open_patch_in_external_editor, src/gui_2.py:App._render_external_editor_panel]
  """
- from src import models
- config = models.load_config()
- editors_config = config.get("tools", {}).get("text_editors", {})
- default_editor = config.get("tools", {}).get("default_editor", {}).get("default_editor")
+ editors_config = config.get("tools", {}).get("text_editors", {}) if config else {}
+ default_editor = config.get("tools", {}).get("default_editor", {}).get("default_editor") if config else None
  ext_config = ExternalEditorConfig.from_dict({
   "editors":        editors_config,
   "default_editor": default_editor,
diff --git a/src/gui_2.py b/src/gui_2.py
index a77a9852..360c2b1e 100644
--- a/src/gui_2.py
+++ b/src/gui_2.py
@@ -1009,7 +1009,7 @@ class App:
     if imgui.menu_item("Save All", "", False)[0]:
      self._flush_to_project()
      self._flush_to_config()
-     models.save_config(self.config)
+     self.save_config()
      self.ai_status = "config saved"
     if imgui.menu_item("Reset Session", "", False)[0]:
      ai_client.reset_session()
@@ -1167,7 +1167,7 @@ class App:
   if "tools" not in self.config:                   self.config["tools"] = {}
   if "default_editor" not in self.config["tools"]: self.config["tools"]["default_editor"] = {}
   self.config["tools"]["default_editor"]["default_editor"] = editor_name
-  models.save_config(self.config)
+  self.save_config()
   self.ai_status = f"Default editor set to: {editor_name}"
   
   _render_path_field("Logs Directory", "ui_logs_dir", "logs_dir", "Directory where session JSON-L logs and artifacts are stored.")
@@ -1192,7 +1192,7 @@ class App:
   }
   cfg_path = paths.get_config_path()
   if cfg_path.exists(): shutil.copy(cfg_path, str(cfg_path) + ".bak")
-  models.save_config(self.config)
+  self.save_config()
   paths.reset_resolved()
   self.init_state()
   self.ai_status = 'paths applied and session reset'
@@ -1308,7 +1308,7 @@ class App:
    if not self._pending_patch_files:
     self._patch_error_message = "No files to edit"
     return
-   launcher = get_default_launcher()
+   launcher = get_default_launcher(self.config)
    editor = launcher.config.get_default()
    if not editor:
     self._patch_error_message = "No external editor configured"
@@ -1479,7 +1479,7 @@ def render_main_interface(app: App) -> None:
   try:
    app._flush_to_project()
    app._flush_to_config()
-   models.save_config(app.config)
+   app.save_config()
   except Exception:
    pass  # silent — don't disrupt the GUI loop
  
@@ -2022,7 +2022,7 @@ def render_projects_panel(app: App) -> None:
  if imgui.button("Save All"):
   app._flush_to_project()
   app._flush_to_config()
-  models.save_config(app.config)
+  app.save_config()
   app.ai_status = "config saved"
  ch, app.ui_word_wrap              = imgui.checkbox("Word-Wrap (Read-only panels)", app.ui_word_wrap)
  ch, app.ui_auto_scroll_comms      = imgui.checkbox("Auto-scroll Comms History", app.ui_auto_scroll_comms)
@@ -2415,7 +2415,7 @@ def render_save_preset_modal(app: App) -> None:
       "multi_viewport": app.ui_multi_viewport
      }
      app.config["layout_presets"] = app.layout_presets
-     models.save_config(app.config)
+     app.save_config()
      app._show_save_preset_modal = False
      app._new_preset_name = ""
     imgui.close_current_popup()
@@ -4211,7 +4211,7 @@ def render_discussion_entry_controls(app: App) -> None:
  imgui.same_line()
  if imgui.button("Clear All"): app.disc_entries.clear()
  imgui.same_line()
- if imgui.button("Save"): app._flush_to_project(); app._flush_to_config(); models.save_config(app.config); app.ai_status = "discussion saved"
+ if imgui.button("Save"): app._flush_to_project(); app._flush_to_config(); app.save_config(); app.ai_status = "discussion saved"
  imgui.same_line()
  if imgui.button("Compress"): app.controller._handle_compress_discussion()
  _, app.ui_auto_add_history = imgui.checkbox("Auto-add message & response to history", app.ui_auto_add_history)
@@ -4773,7 +4773,7 @@ def render_external_editor_panel(app: App) -> None:
  imgui.text("External Editor for Diff Viewing")
  imgui.separator()
  try:
-  launcher = get_default_launcher()
+  launcher = get_default_launcher(app.config)
   editors = launcher.config.editors
   default_name = launcher.config.default_editor
   if not editors:
@@ -4876,7 +4876,7 @@ def render_theme_panel(app: App) -> None:
     if imgui.selectable(p, p == cp)[0]:
      theme.apply(p)
      app._flush_to_config()
-     models.save_config(app.config)
+     app.save_config()
    imgui.end_combo()
 
   imgui.separator()
@@ -4907,7 +4907,7 @@ def render_theme_panel(app: App) -> None:
   imgui.same_line()
   if imgui.button("Apply Font (Requires Restart)"):
    app._flush_to_config()
-   models.save_config(app.config)
+   app.save_config()
    app.ai_status = "Font settings saved. Restart required."
   imgui.separator()
   imgui.text("UI Scale (DPI)")
@@ -4915,14 +4915,14 @@ def render_theme_panel(app: App) -> None:
   if ch:
    theme.set_scale(scale)
    app._flush_to_config()
-   models.save_config(app.config)
+   app.save_config()
 
   imgui.text("Panel Transparency")
   ch_t, trans = imgui.slider_float("##trans", theme.get_transparency(), 0.1, 1.0, "%.2f")
   if ch_t:
    theme.set_transparency(trans)
    app._flush_to_config()
-   models.save_config(app.config)
+   app.save_config()
 
   imgui.text("Panel Item Transparency")
   ch_ct, ctrans = imgui.slider_float("##ctrans", theme.get_child_transparency(), 0.1, 1.0, "%.2f")
@@ -4934,14 +4934,14 @@ def render_theme_panel(app: App) -> None:
    gui_cfg = app.config.setdefault("gui", {})
    gui_cfg["bg_shader_enabled"] = bg.enabled
    app._flush_to_config()
-   models.save_config(app.config)
+   app.save_config()
 
   ch_crt, app.ui_crt_filter = imgui.checkbox("CRT Filter", app.ui_crt_filter)
   if ch_crt:
    gui_cfg = app.config.setdefault("gui", {})
    gui_cfg["crt_filter_enabled"] = app.ui_crt_filter
    app._flush_to_config()
-   models.save_config(app.config)
+   app.save_config()
   
   imgui.separator()
   imgui.text("Tone Mapping (Per-Palette)")
@@ -4949,20 +4949,20 @@ def render_theme_panel(app: App) -> None:
   
   imgui.text("Brightness")
   ch_b, b = imgui.slider_float("##tm_b", theme.get_brightness(curr_p), 0.1, 2.0, "%.2f")
-  if ch_b: theme.set_brightness(curr_p, b); app._flush_to_config(); models.save_config(app.config)
+  if ch_b: theme.set_brightness(curr_p, b); app._flush_to_config(); app.save_config()
   
   imgui.text("Contrast")
   ch_c, c = imgui.slider_float("##tm_c", theme.get_contrast(curr_p), 0.1, 2.0, "%.2f")
-  if ch_c: theme.set_contrast(curr_p, c); app._flush_to_config(); models.save_config(app.config)
+  if ch_c: theme.set_contrast(curr_p, c); app._flush_to_config(); app.save_config()
   
   imgui.text("Gamma")
   ch_g, g = imgui.slider_float("##tm_g", theme.get_gamma(curr_p), 0.1, 3.0, "%.2f")
-  if ch_g: theme.set_gamma(curr_p, g); app._flush_to_config(); models.save_config(app.config)
+  if ch_g: theme.set_gamma(curr_p, g); app._flush_to_config(); app.save_config()
   
   if imgui.button("Reset Tone Mapping"):
    theme.reset_tone_mapping(curr_p)
    app._flush_to_config()
-   models.save_config(app.config)
+   app.save_config()
   
  imgui.end()
  if app.perf_profiling_enabled: app.perf_monitor.end_component("_render_theme_panel")
diff --git a/src/models.py b/src/models.py
index 05e2f181..ad96ddd2 100644
--- a/src/models.py
+++ b/src/models.py
@@ -163,14 +163,20 @@ def _clean_nones(data: Any) -> Any:
   return [_clean_nones(v) for v in data if v is not None]
  return data
 
-def load_config() -> dict[str, Any]:
+def _load_config_from_disk() -> dict[str, Any]:
  """
-  [C: src/multi_agent_conductor.py:ConductorEngine.__init__]
+ Re-read the global config.toml from disk and return the parsed
+ dict. The single source of truth for the in-memory config is
+ the AppController's self.config attribute; this function is the
+ disk I/O primitive that the controller owns. Direct callers in
+ src/ are an architectural smell (bypassing the state owner) and
+ will be flagged by scripts/audit_no_models_config_io.py.
+ [C: src/app_controller.py:AppController.load_config, src/app_controller.py:AppController.__init__]
  """
  with open(get_config_path(), "rb") as f:
   return tomllib.load(f)
 
-def save_config(config: dict[str, Any]) -> None:
+def _save_config_to_disk(config: dict[str, Any]) -> None:
  # tomli_w is loaded on-demand (sub-track 2 of startup_speedup_20260606).
  # If it's already in sys.modules (e.g. warmed up or loaded by a prior
  # call), the import is a fast lookup; otherwise it's a cold load paid
diff --git a/src/multi_agent_conductor.py b/src/multi_agent_conductor.py
index cb4f8d72..37268b59 100644
--- a/src/multi_agent_conductor.py
+++ b/src/multi_agent_conductor.py
@@ -113,7 +113,7 @@ class ConductorEngine:
  Orchestrates the execution of tickets within a track.
  """
 
- def __init__(self, track: Track, event_queue: Optional[events.AsyncEventQueue] = None, auto_queue: bool = False) -> None:
+ def __init__(self, track: Track, event_queue: Optional[events.AsyncEventQueue] = None, auto_queue: bool = False, max_workers: int = 4) -> None:
   self.track = track
   self.event_queue = event_queue
   self.tier_usage = {
@@ -124,15 +124,7 @@ class ConductorEngine:
   }
   self.dag    = TrackDAG(self.track.tickets)
   self.engine = ExecutionEngine(self.dag, auto_queue=auto_queue)
-  
-  # Load MMA config
-  try:
-   config      = models.load_config()
-   mma_cfg     = config.get("mma", {})
-   max_workers = mma_cfg.get("max_workers", 4)
-  except Exception:
-   max_workers = 4
-  
+
   self.pool =           WorkerPool(max_workers=max_workers)
   self._workers_lock =  threading.Lock()
   self._active_workers: dict[str, threading.Thread] = {}
diff --git a/tests/conftest.py b/tests/conftest.py
index 3ceb878e..b9d52bb8 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -285,12 +285,12 @@ def mock_app() -> Generator[App, None, None]:
    Mock version of the App for simple unit tests that don't need a loop.
  """
  with (
-  patch('src.models.load_config', return_value={
+  patch('src.app_controller.AppController.load_config', return_value={
    'ai': {'provider': 'gemini', 'model': 'gemini-2.5-flash-lite'},
    'projects': {'paths': [], 'active': ''},
    'gui': {'show_windows': {}}
   }),
-  patch('src.models.save_config'),
+  patch('src.app_controller.AppController.save_config'),
   patch('src.gui_2.project_manager'),
   patch('src.gui_2.session_logger'),
   patch('src.gui_2.immapp.run'),
@@ -320,12 +320,12 @@ def app_instance() -> Generator[App, None, None]:
   [C: tests/test_gui2_events.py:test_app_subscribes_to_events]
  """
  with (
-  patch('src.models.load_config', return_value={
+  patch('src.app_controller.AppController.load_config', return_value={
    'ai': {'provider': 'gemini', 'model': 'gemini-2.5-flash-lite'},
    'projects': {'paths': [], 'active': ''},
    'gui': {'show_windows': {}}
   }),
-  patch('src.models.save_config'),
+  patch('src.app_controller.AppController.save_config'),
   patch('src.gui_2.project_manager'),
   patch('src.gui_2.session_logger'),
   patch('src.gui_2.immapp.run'),
diff --git a/tests/test_api_hook_extensions.py b/tests/test_api_hook_extensions.py
index 1e4b012c..b9d3fed0 100644
--- a/tests/test_api_hook_extensions.py
+++ b/tests/test_api_hook_extensions.py
@@ -33,7 +33,7 @@ def test_get_indicator_state_integration(live_gui: Any) -> None:
 
 def test_app_processes_new_actions() -> None:
  from src import gui_2
- with patch('src.models.load_config', return_value={}), \
+ with patch('src.app_controller.AppController.load_config', return_value={}), \
    patch('src.performance_monitor.PerformanceMonitor'), \
    patch('src.session_logger.open_session'), \
    patch('src.session_logger.reset_session'), \
diff --git a/tests/test_app_controller_mcp.py b/tests/test_app_controller_mcp.py
index 1651bd9f..06bda40f 100644
--- a/tests/test_app_controller_mcp.py
+++ b/tests/test_app_controller_mcp.py
@@ -49,7 +49,7 @@ def controller(tmp_path):
 def test_app_controller_mcp_loading(tmp_path, monkeypatch):
     # Mock CONFIG_PATH to point to our temp config
     config_file = tmp_path / "config.toml"
-    monkeypatch.setattr(models, "CONFIG_PATH", str(config_file))
+    monkeypatch.setenv("SLOP_CONFIG", str(config_file))
     
     mcp_global_file = tmp_path / "mcp_global.json"
     mcp_global_file.write_text(json.dumps({"mcpServers": {"global": {"command": "echo"}}}))
@@ -75,7 +75,7 @@ active = ""
 
 def test_app_controller_mcp_project_override(tmp_path, monkeypatch):
     config_file = tmp_path / "config.toml"
-    monkeypatch.setattr(models, "CONFIG_PATH", str(config_file))
+    monkeypatch.setenv("SLOP_CONFIG", str(config_file))
     
     project_file = tmp_path / "project.toml"
     mcp_project_file = tmp_path / "mcp_project.json"
diff --git a/tests/test_arch_boundary_phase2.py b/tests/test_arch_boundary_phase2.py
index e822cb52..235e9cdf 100644
--- a/tests/test_arch_boundary_phase2.py
+++ b/tests/test_arch_boundary_phase2.py
@@ -44,7 +44,7 @@ class TestArchBoundaryPhase2(unittest.TestCase):
   from src.app_controller import AppController
     
   # Use a real AppController to test its _confirm_and_run
-  with patch('src.models.load_config', return_value={}), \
+  with patch('src.app_controller.AppController.load_config', return_value={}), \
    patch('src.performance_monitor.PerformanceMonitor'), \
    patch('src.session_logger.open_session'), \
    patch('src.session_logger.reset_session'), \
@@ -67,7 +67,7 @@ class TestArchBoundaryPhase2(unittest.TestCase):
   """When pre_tool_callback returns None (rejected), dispatch must NOT be called."""
   from src.app_controller import AppController
     
-  with patch('src.models.load_config', return_value={}), \
+  with patch('src.app_controller.AppController.load_config', return_value={}), \
    patch('src.performance_monitor.PerformanceMonitor'), \
    patch('src.session_logger.open_session'), \
    patch('src.session_logger.reset_session'), \
diff --git a/tests/test_auto_slices.py b/tests/test_auto_slices.py
index d75ff319..e0d2632a 100644
--- a/tests/test_auto_slices.py
+++ b/tests/test_auto_slices.py
@@ -6,7 +6,7 @@ from src import models
 @pytest.fixture
 def mock_app():
  with (
-  patch('src.models.load_config', return_value={
+  patch('src.app_controller.AppController.load_config', return_value={
    "ai": {"provider": "gemini", "model": "model-1"},
    "projects": {"paths": [], "active": ""},
    "gui": {"show_windows": {}}
diff --git a/tests/test_discussion_takes_gui.py b/tests/test_discussion_takes_gui.py
index 85c8b4ed..6ab5b52b 100644
--- a/tests/test_discussion_takes_gui.py
+++ b/tests/test_discussion_takes_gui.py
@@ -6,8 +6,8 @@ from src.gui_2 import App
 @pytest.fixture
 def app_instance():
  with (
-  patch('src.models.load_config', return_value={'ai': {'provider': 'gemini', 'model': 'gemini-2.5-flash-lite'}, 'projects': {}}),
-  patch('src.models.save_config'),
+  patch('src.app_controller.AppController.load_config', return_value={'ai': {'provider': 'gemini', 'model': 'gemini-2.5-flash-lite'}, 'projects': {}}),
+  patch('src.app_controller.AppController.save_config'),
   patch('src.gui_2.project_manager'),
   patch('src.gui_2.session_logger'),
   patch('src.gui_2.immapp.run'),
diff --git a/tests/test_gui_events_v2.py b/tests/test_gui_events_v2.py
index 5503bdf0..8921dfca 100644
--- a/tests/test_gui_events_v2.py
+++ b/tests/test_gui_events_v2.py
@@ -6,7 +6,7 @@ from src.events import UserRequestEvent
 @pytest.fixture
 def mock_gui() -> App:
  with (
-  patch('src.models.load_config', return_value={
+  patch('src.app_controller.AppController.load_config', return_value={
     "ai": {"provider": "gemini", "model": "model-1"},
     "projects": {"paths": [], "active": ""},
     "gui": {"show_windows": {}}
diff --git a/tests/test_gui_paths.py b/tests/test_gui_paths.py
index d0b5dd33..70817a7c 100644
--- a/tests/test_gui_paths.py
+++ b/tests/test_gui_paths.py
@@ -10,6 +10,7 @@ class MockApp:
   self.ui_scripts_dir = '/mock/scripts'
   self.config = {"paths": {}}
   self.ai_status = ""
+  self.save_config = MagicMock()
  
  def init_state(self):
   """
@@ -23,8 +24,7 @@ class MockApp:
 def test_save_paths():
  mock_app = MockApp()
  
- with patch('src.models.save_config') as mock_save, \
-      patch('shutil.copy') as mock_copy, \
+ with patch('shutil.copy') as mock_copy, \
       patch('src.paths.get_config_path') as mock_get_cfg, \
       patch('src.paths.reset_resolved') as mock_reset, \
       patch.object(MockApp, 'init_state') as mock_init:
@@ -37,7 +37,7 @@ def test_save_paths():
   
   # Verify config update
   assert 'conductor_dir' not in mock_app.config['paths']
-  mock_save.assert_called_once()
+  mock_app.save_config.assert_called_once()
   mock_copy.assert_called_once()
   assert 'applied' in mock_app.ai_status
   mock_reset.assert_called_once()
diff --git a/tests/test_gui_synthesis.py b/tests/test_gui_synthesis.py
index f2b74b57..9e7929f3 100644
--- a/tests/test_gui_synthesis.py
+++ b/tests/test_gui_synthesis.py
@@ -6,8 +6,8 @@ from src.gui_2 import App
 @pytest.fixture
 def app_instance():
  with (
-  patch('src.models.load_config', return_value={'ai': {'provider': 'gemini', 'model': 'gemini-2.5-flash-lite'}, 'projects': {}}),
-  patch('src.models.save_config'),
+  patch('src.app_controller.AppController.load_config', return_value={'ai': {'provider': 'gemini', 'model': 'gemini-2.5-flash-lite'}, 'projects': {}}),
+  patch('src.app_controller.AppController.save_config'),
   patch('src.gui_2.project_manager'),
   patch('src.gui_2.session_logger'),
   patch('src.gui_2.immapp.run'),
diff --git a/tests/test_headless_service.py b/tests/test_headless_service.py
index 2ea99ede..066f2086 100644
--- a/tests/test_headless_service.py
+++ b/tests/test_headless_service.py
@@ -11,7 +11,7 @@ from src.app_controller import AppController
 
 class TestHeadlessAPI(unittest.TestCase):
     def setUp(self) -> None:
-     with patch('src.models.load_config', return_value={'ai': {'provider': 'gemini', 'model': 'gemini-2.5-flash-lite'}, 'projects': {}, 'gui': {'show_windows': {}}}), \
+     with patch('src.app_controller.AppController.load_config', return_value={'ai': {'provider': 'gemini', 'model': 'gemini-2.5-flash-lite'}, 'projects': {}, 'gui': {'show_windows': {}}}), \
           patch('src.session_logger.open_session'), \
           patch('src.session_logger.reset_session'), \
           patch('src.ai_client.set_provider'), \
diff --git a/tests/test_hooks.py b/tests/test_hooks.py
index 3d7e75c7..e61b4f5f 100644
--- a/tests/test_hooks.py
+++ b/tests/test_hooks.py
@@ -11,7 +11,7 @@ def test_hooks_enabled_via_cli(monkeypatch: pytest.MonkeyPatch) -> None:
  from src.gui_2 import App
  from unittest.mock import patch
  monkeypatch.setattr("sys.argv", ["sloppy.py", "--enable-test-hooks"])
- with patch('src.models.load_config', return_value={}), \
+ with patch('src.app_controller.AppController.load_config', return_value={}), \
    patch('src.performance_monitor.PerformanceMonitor'), \
    patch('src.session_logger.open_session'), \
    patch('src.session_logger.reset_session'), \
@@ -23,7 +23,7 @@ def test_hooks_enabled_via_cli(monkeypatch: pytest.MonkeyPatch) -> None:
 def test_hooks_disabled_by_default() -> None:
  from src.gui_2 import App
  from unittest.mock import patch
- with patch('src.models.load_config', return_value={}), \
+ with patch('src.app_controller.AppController.load_config', return_value={}), \
    patch('src.performance_monitor.PerformanceMonitor'), \
    patch('src.session_logger.open_session'), \
    patch('src.session_logger.reset_session'), \
diff --git a/tests/test_layout_reorganization.py b/tests/test_layout_reorganization.py
index bd55f984..4d5d8fce 100644
--- a/tests/test_layout_reorganization.py
+++ b/tests/test_layout_reorganization.py
@@ -45,7 +45,7 @@ def test_old_windows_removed_from_gui2(app_instance_simple: Any) -> None:
 def app_instance_simple() -> Any:
  from unittest.mock import patch
  from src.gui_2 import App
- with patch('src.models.load_config', return_value={'ai': {}, 'projects': {}, 'gui': {'show_windows': {}}}), \
+ with patch('src.app_controller.AppController.load_config', return_value={'ai': {}, 'projects': {}, 'gui': {'show_windows': {}}}), \
    patch('src.app_controller.AppController._init_ai_and_hooks'), \
    patch('src.app_controller.AppController._fetch_models'), \
    patch('src.app_controller.AppController._prune_old_logs'), \
diff --git a/tests/test_mma_dashboard_refresh.py b/tests/test_mma_dashboard_refresh.py
index dd04ed37..5dc64e9e 100644
--- a/tests/test_mma_dashboard_refresh.py
+++ b/tests/test_mma_dashboard_refresh.py
@@ -7,8 +7,8 @@ from src.gui_2 import App
 @pytest.fixture
 def app_instance() -> Any:
  with (
-  patch("src.models.load_config", return_value={"ai": {}, "projects": {}}),
-  patch("src.models.save_config"),
+  patch("src.app_controller.AppController.load_config", return_value={"ai": {}, "projects": {}}),
+  patch("src.app_controller.AppController.save_config"),
   patch("src.gui_2.project_manager"),
   patch("src.app_controller.project_manager") as mock_pm,
   patch("src.gui_2.session_logger"),
diff --git a/tests/test_models_no_top_level_tomli_w.py b/tests/test_models_no_top_level_tomli_w.py
index 69b1ddd8..99fb2758 100644
--- a/tests/test_models_no_top_level_tomli_w.py
+++ b/tests/test_models_no_top_level_tomli_w.py
@@ -46,7 +46,7 @@ def test_models_can_still_call_save_config_after_lazy_load() -> None:
   "theme": {"palette": "solarized_dark", "font_size": 16.0},
  }
  try:
-  src.models.save_config(config)
+  src.models._save_config_to_disk(config)
  except Exception as e:
   pytest.fail(f"save_config raised after lazy tomli_w: {e}")
  finally:
@@ -63,7 +63,7 @@ def test_save_config_uses_tomli_w_on_demand() -> None:
  assert "tomli_w" not in sys.modules
  # Call save_config - this should trigger the import
  try:
-  src.models.save_config({"test_key": "test_value"})
+  src.models._save_config_to_disk({"test_key": "test_value"})
  except Exception:
   # We don't care if the save itself fails; we just want to verify
   # the import happened.
diff --git a/tests/test_parallel_execution.py b/tests/test_parallel_execution.py
index e811ab30..9a9683b8 100644
--- a/tests/test_parallel_execution.py
+++ b/tests/test_parallel_execution.py
@@ -71,20 +71,17 @@ from src.models import Track, Ticket
 from src.multi_agent_conductor import ConductorEngine
 
 @patch('src.multi_agent_conductor.run_worker_lifecycle')
-@patch('src.models.load_config')
-def test_conductor_engine_pool_integration(mock_load_config, mock_lifecycle):
- # Mock config to set max_workers=2
- mock_load_config.return_value = {"mma": {"max_workers": 2}}
- 
+def test_conductor_engine_pool_integration(mock_lifecycle):
  # Create 4 independent tickets
  tickets = [
   Ticket(id=f"t{i}", description=f"task {i}", status="todo")
   for i in range(4)
  ]
  track = Track(id="test_track", description="test", tickets=tickets)
- 
- # Set up engine with auto_queue
- engine = ConductorEngine(track, auto_queue=True)
+
+ # Set up engine with auto_queue and explicit max_workers=2.
+ # ConductorEngine no longer reads config itself; the caller passes max_workers.
+ engine = ConductorEngine(track, auto_queue=True, max_workers=2)
  sys.stderr.write(f"[TEST] engine.pool.max_workers = {engine.pool.max_workers}\n")
  assert engine.pool.max_workers == 2
  
diff --git a/tests/test_phase6_engine.py b/tests/test_phase6_engine.py
index 85d39060..81b48d47 100644
--- a/tests/test_phase6_engine.py
+++ b/tests/test_phase6_engine.py
@@ -47,7 +47,7 @@ def test_per_tier_model_persistence():
    patch("src.gui_2.project_manager.load_project", return_value={}), 
    patch("src.gui_2.project_manager.migrate_from_legacy_config", return_value={}), 
    patch("src.gui_2.project_manager.save_project"), 
-   patch("src.models.save_config"),
+   patch("src.app_controller.AppController.save_config"),
    patch("src.gui_2.theme.load_from_config"), 
    patch("src.gui_2.ai_client.set_provider"), 
    patch("src.gui_2.ai_client.list_models", return_value=["gpt-4", "claude-3"]), 
diff --git a/tests/test_process_pending_gui_tasks.py b/tests/test_process_pending_gui_tasks.py
index 9e8ab61a..9463c717 100644
--- a/tests/test_process_pending_gui_tasks.py
+++ b/tests/test_process_pending_gui_tasks.py
@@ -7,8 +7,8 @@ from src.gui_2 import App
 @pytest.fixture
 def app_instance() -> Generator[App, None, None]:
  with (
-  patch('src.models.load_config', return_value={'ai': {'provider': 'gemini', 'model': 'gemini-2.5-flash-lite'}, 'projects': {}}),
-  patch('src.models.save_config'),
+  patch('src.app_controller.AppController.load_config', return_value={'ai': {'provider': 'gemini', 'model': 'gemini-2.5-flash-lite'}, 'projects': {}}),
+  patch('src.app_controller.AppController.save_config'),
   patch('src.gui_2.project_manager'),
   patch('src.gui_2.session_logger'),
   patch('src.gui_2.immapp.run'),
diff --git a/tests/test_rag_integration.py b/tests/test_rag_integration.py
index 3f3126c9..dbf63f1b 100644
--- a/tests/test_rag_integration.py
+++ b/tests/test_rag_integration.py
@@ -31,7 +31,7 @@ def test_rag_integration(mock_project):
  # 1. Initializes a mock project and AppController.
  # We patch several components to avoid side effects during initialization.
  with patch('src.app_controller.AppController._fetch_models'), \
-      patch('src.models.load_config', return_value={}), \
+      patch('src.app_controller.AppController.load_config', return_value={}), \
       patch('src.paths.get_full_path_info', return_value={'logs_dir': {'path': mock_project}, 'scripts_dir': {'path': mock_project}}), \
       patch('src.theme_2.load_from_config'):
   app = AppController()
diff --git a/tests/test_symbol_parsing.py b/tests/test_symbol_parsing.py
index eca567b8..8ca26290 100644
--- a/tests/test_symbol_parsing.py
+++ b/tests/test_symbol_parsing.py
@@ -8,7 +8,7 @@ from src import events
 @pytest.fixture
 def controller():
  with (
-  patch('src.models.load_config', return_value={
+  patch('src.app_controller.AppController.load_config', return_value={
    "ai": {"provider": "gemini", "model": "model-1"},
    "projects": {"paths": [], "active": ""},
    "gui": {"show_windows": {}}
diff --git a/tests/test_system_prompt_exposure.py b/tests/test_system_prompt_exposure.py
index b96432bf..61a696bf 100644
--- a/tests/test_system_prompt_exposure.py
+++ b/tests/test_system_prompt_exposure.py
@@ -49,7 +49,7 @@ class TestSystemPromptExposure(unittest.TestCase):
   self.assertIn("You are a helpful coding assistant", combined)
   self.assertNotIn("Overridden Prompt", combined)
 
- @patch('src.models.load_config')
+ @patch('src.app_controller.AppController.load_config')
  @patch('src.paths.get_full_path_info')
  @patch('src.project_manager.load_project')
  @patch('src.ai_client.set_tool_preset')
diff --git a/tests/test_tiered_aggregation.py b/tests/test_tiered_aggregation.py
index e987490b..cf8b709f 100644
--- a/tests/test_tiered_aggregation.py
+++ b/tests/test_tiered_aggregation.py
@@ -31,7 +31,7 @@ def test_app_controller_do_generate_uses_persona_strategy(mock_build):
     with patch("pathlib.Path.write_text"):
      with patch.object(app, "_flush_to_project"):
       with patch.object(app, "_flush_to_config"):
-       with patch("src.models.save_config"):
+       with patch("src.app_controller.AppController.save_config"):
         full_md, path, file_items, stable_md, disc = app._do_generate()
     
  # Verify aggregate.run and build_markdown_no_history received aggregation_strategy="full"