diff --git a/sloppy.py b/sloppy.py
index ca3f62ff..bb299355 100644
--- a/sloppy.py
+++ b/sloppy.py
@@ -42,9 +42,8 @@ args: argparse.Namespace = argparse.Namespace()  # type: ignore[assignment]
 if __name__ == "__main__":
  args = parser.parse_args()
  from pathlib import Path
- from src.paths import set_config_override
- if args.config:
-  set_config_override(Path(args.config).resolve())
+ from src.paths import initialize_paths
+ initialize_paths(Path(args.config).resolve() if args.config else None)
  if args.web_host is not None:
   with startup_profiler.phase("web_host_imports"):
    from imgui_bundle import hello_imgui
diff --git a/src/app_controller.py b/src/app_controller.py
index b571811c..cc5ba00f 100644
--- a/src/app_controller.py
+++ b/src/app_controller.py
@@ -1804,7 +1804,7 @@ class AppController:
     spath = Path(proj_paths['scripts_dir'])
     if not spath.is_absolute(): spath = project_root / spath
     os.environ['SLOP_SCRIPTS_DIR'] = str(spath)
-   paths.reset_resolved()
+   paths.initialize_paths(paths.get_config_path())
 
   path_info           = paths.get_full_path_info()
   self.ui_logs_dir    = str(path_info['logs_dir']['path'])
diff --git a/src/gui_2.py b/src/gui_2.py
index 0d0cc1f7..a96d5202 100644
--- a/src/gui_2.py
+++ b/src/gui_2.py
@@ -1311,7 +1311,7 @@ class App:
   cfg_path = paths.get_config_path()
   if cfg_path.exists(): shutil.copy(cfg_path, str(cfg_path) + ".bak")
   self.save_config()
-  paths.reset_resolved()
+  paths.initialize_paths(cfg_path)
   self.init_state()
   self.ai_status = 'paths applied and session reset'
 
@@ -2341,10 +2341,17 @@ def render_paths_panel(app: App) -> None:
 
  render_path_field("Logs Directory", "ui_logs_dir", "logs_dir", "Directory where session JSON-L logs and artifacts are stored.")
  render_path_field("Scripts Directory", "ui_scripts_dir", "scripts_dir", "Directory for AI-generated PowerShell scripts.")
- 
+
  imgui.separator()
  if imgui.button("Apply", imgui.ImVec2(120, 0)): app._save_paths()
  imgui.same_line()
+ if imgui.button("Refresh Paths", imgui.ImVec2(140, 0)):
+  paths.initialize_paths(paths.get_config_path())
+  app.init_state()
+  app.ai_status = "paths reloaded from config.toml"
+ if imgui.is_item_hovered():
+  imgui.set_tooltip("Re-read [paths] section from config.toml and rebuild the PathsConfig singleton. Use after editing config.toml directly or after importing a new config.")
+ imgui.same_line()
  if imgui.button("Reset", imgui.ImVec2(120, 0)):
   app.init_state()
   app.ai_status = "paths reset to defaults"
diff --git a/src/paths.py b/src/paths.py
index e2e4ff8f..005becbb 100644
--- a/src/paths.py
+++ b/src/paths.py
@@ -1,189 +1,231 @@
 """
-Paths - Centralized path resolution for configuration and environment variables.
+Paths - Single source of truth for all application paths.
 
-This module provides centralized path resolution for all configurable paths in the application.
- All paths can be overridden via environment variables or config.toml.
+All paths are resolved ONCE at startup via `initialize_paths(config_path)`,
+which reads the active config.toml's `[paths]` section (with env-var overrides)
+and builds an immutable `PathsConfig` snapshot. Path getters are trivial
+lookups into this snapshot.
 
-Environment Variables:
- SLOP_CONFIG: Path to config.toml
- SLOP_LOGS_DIR: Path to logs directory
- SLOP_SCRIPTS_DIR: Path to generated scripts directory
+**Usage contract:**
 
-Configuration (config.toml):
- [paths]
- logs_dir = "logs/sessions"
- scripts_dir = "scripts/generated"
+1. Call `initialize_paths(config_path)` ONCE at process startup, BEFORE any
+   path getter is invoked. This is the only correct entry point.
+2. After init, all `get_*_path()` functions return cached `Path` objects.
+3. To change paths (e.g., in tests), call `initialize_paths(new_config_path)`
+   again — atomic swap under lock. Do not mutate `PathsConfig` instances;
+   they are frozen.
 
-Path Functions:
- get_config_path() -> Path to config.toml
- get_conductor_dir(project_path=None) -> Path to conductor directory
- get_logs_dir() -> Path to logs/sessions
- get_scripts_dir() -> Path to scripts/generated
- get_tracks_dir(project_path=None) -> Path to conductor/tracks
- get_track_state_dir(track_id, project_path=None) -> Path to conductor/tracks/<track_id>
- get_archive_dir(project_path=None) -> Path to conductor/archive
+**Thread safety:** The singleton swap is guarded by an RLock. `PathsConfig`
+is a `@dataclass(frozen=True)`, so reads of individual fields are atomic.
+Reader threads see a consistent snapshot; writer threads serialize through
+the lock. No partial writes.
 
-Resolution Order:
- 1. Check project-specific manual_slop.toml (for conductor paths)
- 2. Check environment variable (for logs/scripts)
- 3. Check config.toml [paths] section (for logs/scripts)
- 4. Fall back to default
+**Resolution priority** (per key, in `initialize_paths`):
+  1. Env var (e.g., `SLOP_GLOBAL_PRESETS`) if set
+  2. `config.toml [paths]` entry if present
+  3. Default `<project_root>/<default_filename>`
 
-Usage:
- from src.paths import get_logs_dir, get_scripts_dir
+**Codepath ordering:**
 
- logs_dir = get_logs_dir()
- scripts_dir = get_scripts_dir()
+The major codepaths that consume paths are:
+- `sloppy.py` (production GUI entry point)
+- `src/app_controller.py:AppController.__init__`
+- `src/presets.py`, `src/tool_presets.py`, `src/personas.py`, etc.
 
-See Also:
- - docs/guide_tools.md for configuration documentation
- - src/session_logger.py for logging paths
- - src/project_manager.py for project paths
+`initialize_paths()` must run BEFORE any of these. In sloppy.py, it runs
+at the top of `__main__`. In tests, it runs at conftest module body (before
+any src/ import). In other contexts (e.g., direct library use), the caller
+is responsible.
+
+If a path getter is called before `initialize_paths()`, a `RuntimeError`
+is raised. This catches the "bad programmer" case where ordering is wrong.
 """
 import os
+import threading
 import tomllib
 
+from dataclasses import dataclass
 from pathlib import Path
-from typing  import Optional, Any
+from typing import Optional, Any
 
 
-_RESOLVED: dict[str, Path] = {}
-
-_CONFIG_OVERRIDE: Path | None = None
+@dataclass(frozen=True)
+class PathsConfig:
+ """Immutable snapshot of resolved paths. Created ONCE per process.
+ [C: src/paths.py:initialize_paths, src/paths.py:_cfg]"""
+ config_path:        Path
+ presets:            Path
+ tool_presets:       Path
+ personas:           Path
+ themes:             Path
+ workspace_profiles: Path
+ credentials:        Path
+ logs_dir:           Path
+ scripts_dir:        Path
 
 
-def set_config_override(path: Path | None) -> None:
- """
- Set the active config.toml path. Pass None to use the default
- <project_root>/config.toml. The CLI --config flag is the ONLY
- supported override mechanism; the historical SLOP_CONFIG env var
- fallback has been removed (per test_sandbox_hardening_20260619 FR2).
- [C: sloppy.py:main, tests/conftest.py]
- """
- global _CONFIG_OVERRIDE
- _CONFIG_OVERRIDE = path
- _RESOLVED.clear()
+_PATHS_CONFIG: Optional[PathsConfig] = None
+_PATHS_LOCK = threading.RLock()
 
 
+def _resolve_path(env_var: str, config_key: str, default: Path, config_path: Path) -> Path:
+ """Internal: resolve one path from env var -> config [paths] -> default.
+ Called only from initialize_paths(). Not thread-safe; caller holds lock."""
+ root_dir = Path(__file__).resolve().parent.parent
+ if env_var in os.environ:
+  return Path(os.environ[env_var])
+ try:
+  with open(config_path, "rb") as f:
+   cfg = tomllib.load(f)
+  if "paths" in cfg and config_key in cfg["paths"]:
+   p = Path(cfg["paths"][config_key])
+   return p if p.is_absolute() else root_dir / p
+ except (FileNotFoundError, tomllib.TOMLDecodeError):
+  pass
+ return default if default.is_absolute() else root_dir / default
+
+
+def initialize_paths(config_path: Optional[Path] = None) -> PathsConfig:
+ """Initialize the global paths singleton. Call this ONCE at startup,
+ BEFORE any path getter is invoked. Atomic swap under RLock.
+
+ If config_path is None, uses the default `<project_root>/config.toml`.
+
+ This is the SOLE entry point for setting the path graph at runtime.
+ Tests re-init to reset.
+
+ Raises:
+   OSError: if the config_path cannot be opened (other than FileNotFoundError
+            which is treated as "no [paths] overrides, use defaults")
+   TypeError: if config_path is not a Path
+
+ Returns:
+   The newly installed PathsConfig snapshot.
+ [C: src/paths.py:_cfg, tests/conftest.py:_setup_test_paths, sloppy.py:main]"""
+ global _PATHS_CONFIG
+ if config_path is None:
+  root_dir = Path(__file__).resolve().parent.parent
+  config_path = root_dir / "config.toml"
+ config_path = Path(config_path).resolve()
+
+ root_dir = Path(__file__).resolve().parent.parent
+ cfg = PathsConfig(
+  config_path        = config_path,
+  presets            = _resolve_path("SLOP_GLOBAL_PRESETS",        "presets",            root_dir / "presets.toml",            config_path),
+  tool_presets       = _resolve_path("SLOP_GLOBAL_TOOL_PRESETS",  "tool_presets",       root_dir / "tool_presets.toml",       config_path),
+  personas           = _resolve_path("SLOP_GLOBAL_PERSONAS",       "personas",           root_dir / "personas.toml",           config_path),
+  themes             = _resolve_path("SLOP_GLOBAL_THEMES",         "themes",             root_dir / "themes",                  config_path),
+  workspace_profiles = _resolve_path("SLOP_GLOBAL_WORKSPACE_PROFILES", "workspace_profiles", root_dir / "workspace_profiles.toml", config_path),
+  credentials        = _resolve_path("SLOP_CREDENTIALS",           "credentials",        root_dir / "credentials.toml",        config_path),
+  logs_dir           = _resolve_path("SLOP_LOGS_DIR",              "logs_dir",           root_dir / "logs" / "sessions",       config_path),
+  scripts_dir        = _resolve_path("SLOP_SCRIPTS_DIR",           "scripts_dir",        root_dir / "scripts" / "generated",   config_path),
+ )
+ with _PATHS_LOCK:
+  _PATHS_CONFIG = cfg
+ return cfg
+
+
+def _cfg() -> PathsConfig:
+ """Internal: get the current singleton, raising if uninitialized."""
+ if _PATHS_CONFIG is None:
+  raise RuntimeError(
+   "src.paths not initialized. Call paths.initialize_paths(<config.toml>) "
+   "BEFORE any path getter. See src/paths.py docstring for codepath ordering."
+  )
+ return _PATHS_CONFIG
+
+
+# === Trivial getters (single source of truth) ===
+
 def get_config_path() -> Path:
- """
- Returns the active config.toml. If a CLI override is set, returns it.
- Otherwise returns the default <project_root>/config.toml.
+ """Active config.toml path. Frozen at initialize_paths() time.
  [C: src/app_controller.py:AppController.load_config,
     src/app_controller.py:AppController.init_state,
     src/models.py:_load_config_from_disk,
-    tests/test_test_sandbox.py]
- """
- if _CONFIG_OVERRIDE is not None:
-  return _CONFIG_OVERRIDE
- root_dir = Path(__file__).resolve().parent.parent
- return root_dir / "config.toml"
+    tests/test_test_sandbox.py]"""
+ return _cfg().config_path
 
 def get_global_presets_path() -> Path:
- """
- [C: src/presets.py:PresetManager.__init__, src/presets.py:PresetManager.delete_preset, src/presets.py:PresetManager.get_preset_scope]
- """
- if "presets" not in _RESOLVED:
-  _RESOLVED["presets"] = _resolve_path("SLOP_GLOBAL_PRESETS", "presets", "presets.toml")
- return _RESOLVED["presets"]
+ """Global presets file. Frozen at initialize_paths() time.
+ [C: src/presets.py:PresetManager.__init__, src/presets.py:PresetManager.delete_preset, src/presets.py:PresetManager.get_preset_scope]"""
+ return _cfg().presets
 
 def get_project_presets_path(project_root: Path) -> Path:
- """
- [C: src/presets.py:PresetManager.delete_preset, src/presets.py:PresetManager.get_preset_scope, src/presets.py:PresetManager.project_path]
- """
+ """Project-specific presets file. Computed from project_root (no cache).
+ [C: src/presets.py:PresetManager.delete_preset, src/presets.py:PresetManager.get_preset_scope, src/presets.py:PresetManager.project_path]"""
  return project_root / "project_presets.toml"
 
 def get_global_tool_presets_path() -> Path:
- """
- [C: src/tool_presets.py:ToolPresetManager._get_path, src/tool_presets.py:ToolPresetManager.load_all_bias_profiles, src/tool_presets.py:ToolPresetManager.load_all_presets]
- """
- if "tool_presets" not in _RESOLVED:
-  _RESOLVED["tool_presets"] = _resolve_path("SLOP_GLOBAL_TOOL_PRESETS", "tool_presets", "tool_presets.toml")
- return _RESOLVED["tool_presets"]
+ """Global tool presets file. Frozen at initialize_paths() time.
+ [C: src/tool_presets.py:ToolPresetManager._get_path, src/tool_presets.py:ToolPresetManager.load_all_bias_profiles, src/tool_presets.py:ToolPresetManager.load_all_presets]"""
+ return _cfg().tool_presets
 
 def get_project_tool_presets_path(project_root: Path) -> Path:
- """
- [C: src/tool_presets.py:ToolPresetManager._get_path, src/tool_presets.py:ToolPresetManager.load_all_bias_profiles, src/tool_presets.py:ToolPresetManager.load_all_presets]
- """
+ """[C: src/tool_presets.py:ToolPresetManager._get_path, src/tool_presets.py:ToolPresetManager.load_all_bias_profiles, src/tool_presets.py:ToolPresetManager.load_all_presets]"""
  return project_root / "project_tool_presets.toml"
 
 def get_global_personas_path() -> Path:
- """
- [C: src/personas.py:PersonaManager._get_path, src/personas.py:PersonaManager.get_persona_scope, src/personas.py:PersonaManager.load_all]
- """
- if "personas" not in _RESOLVED:
-  _RESOLVED["personas"] = _resolve_path("SLOP_GLOBAL_PERSONAS", "personas", "personas.toml")
- return _RESOLVED["personas"]
+ """Global personas file. Frozen at initialize_paths() time.
+ [C: src/personas.py:PersonaManager._get_path, src/personas.py:PersonaManager.get_persona_scope, src/personas.py:PersonaManager.load_all]"""
+ return _cfg().personas
 
 def get_project_personas_path(project_root: Path) -> Path:
- """
- [C: src/personas.py:PersonaManager._get_path, src/personas.py:PersonaManager.get_persona_scope, src/personas.py:PersonaManager.load_all]
- """
+ """[C: src/personas.py:PersonaManager._get_path, src/personas.py:PersonaManager.get_persona_scope, src/personas.py:PersonaManager.load_all]"""
  return project_root / "project_personas.toml"
 
 def get_global_themes_path() -> Path:
- """
- [C: src/theme_2.py:load_themes_from_disk]
- """
- if "themes" not in _RESOLVED:
-  _RESOLVED["themes"] = _resolve_path("SLOP_GLOBAL_THEMES", "themes", "themes")
- return _RESOLVED["themes"]
+ """Global themes directory. Frozen at initialize_paths() time.
+ [C: src/theme_2.py:load_themes_from_disk]"""
+ return _cfg().themes
 
 def get_project_themes_path(project_root: Path) -> Path:
- """
- [C: src/theme_2.py:load_themes_from_disk]
- """
+ """[C: src/theme_2.py:load_themes_from_disk]"""
  return project_root / "project_themes.toml"
 
 def get_global_workspace_profiles_path() -> Path:
- """
- [C: src/workspace_manager.py:WorkspaceManager._get_path, src/workspace_manager.py:WorkspaceManager.load_all_profiles]
- """
- if "workspace_profiles" not in _RESOLVED:
-  _RESOLVED["workspace_profiles"] = _resolve_path("SLOP_GLOBAL_WORKSPACE_PROFILES", "workspace_profiles", "workspace_profiles.toml")
- return _RESOLVED["workspace_profiles"]
+ """Global workspace profiles file. Frozen at initialize_paths() time.
+ [C: src/workspace_manager.py:WorkspaceManager._get_path, src/workspace_manager.py:WorkspaceManager.load_all_profiles]"""
+ return _cfg().workspace_profiles
 
 def get_project_workspace_profiles_path(project_root: Path) -> Path:
- """
- [C: src/workspace_manager.py:WorkspaceManager._get_path, src/workspace_manager.py:WorkspaceManager.load_all_profiles]
- """
+ """[C: src/workspace_manager.py:WorkspaceManager._get_path, src/workspace_manager.py:WorkspaceManager.load_all_profiles]"""
  return project_root / ".ai" / "workspace_profiles.toml"
 
 def get_credentials_path() -> Path:
- """
- [C: src/mcp_client.py:_is_allowed]
- """
- if "credentials" not in _RESOLVED:
-  _RESOLVED["credentials"] = _resolve_path("SLOP_CREDENTIALS", "credentials", "credentials.toml")
- return _RESOLVED["credentials"]
+ """Global credentials file. Frozen at initialize_paths() time.
+ [C: src/mcp_client.py:_is_allowed]"""
+ return _cfg().credentials
+
+def get_logs_dir() -> Path:
+ """Logs directory (contains session subdirs). Frozen at initialize_paths() time.
+ [C: src/session_logger.py:close_session, src/session_logger.py:open_session, tests/test_paths.py:test_config_overrides, tests/test_paths.py:test_default_paths, tests/test_paths.py:test_env_var_overrides, tests/test_paths.py:test_precedence]"""
+ return _cfg().logs_dir
+
+def get_scripts_dir() -> Path:
+ """Generated scripts directory. Frozen at initialize_paths() time.
+ [C: src/session_logger.py:log_tool_call, src/session_logger.py:open_session, tests/test_paths.py:test_config_overrides, tests/test_paths.py:test_default_paths]"""
+ return _cfg().scripts_dir
+
+def get_tracks_dir(project_path: Optional[str] = None) -> Path:
+ """[C: src/project_manager.py:get_all_tracks, tests/test_paths.py:test_conductor_dir_project_relative]"""
+ return get_conductor_dir(project_path) / "tracks"
+
+def get_track_state_dir(track_id: str, project_path: Optional[str] = None) -> Path:
+ """[C: src/project_manager.py:load_track_state, src/project_manager.py:save_track_state, tests/test_paths.py:test_conductor_dir_project_relative]"""
+ return get_tracks_dir(project_path) / track_id
+
+def get_archive_dir(project_path: Optional[str] = None) -> Path:
+ """[C: tests/test_paths.py:test_conductor_dir_project_relative]"""
+ return get_conductor_dir(project_path) / "archive"
 
-def _resolve_path(env_var: str, config_key: str, default: str) -> Path:
- root_dir = Path(__file__).resolve().parent.parent
- p = None
- if env_var in os.environ:
-  p = Path(os.environ[env_var])
- else:
-  try:
-   with open(get_config_path(), "rb") as f:
-    cfg = tomllib.load(f)
-   if "paths" in cfg and config_key in cfg["paths"]:
-    p = Path(cfg["paths"][config_key])
-  except (FileNotFoundError, tomllib.TOMLDecodeError):
-   pass
- if p is None:
-  p = Path(default)
- if not p.is_absolute():
-  return root_dir / p
- return p
 
 def _get_project_conductor_dir_from_toml(project_root: Path) -> Optional[Path]:
- # Look for manual_slop.toml in project_root
+ """Look for manual_slop.toml in project_root for [conductor] dir override."""
  toml_path = project_root / 'manual_slop.toml'
  if not toml_path.exists(): return None
  try:
   with open(toml_path, 'rb') as f:
    data = tomllib.load(f)
-  # Check [conductor] dir = '...'
   c_dir = data.get('conductor', {}).get('dir')
   if c_dir:
    p = Path(c_dir)
@@ -192,79 +234,44 @@ def _get_project_conductor_dir_from_toml(project_root: Path) -> Optional[Path]:
  except: pass
  return None
 
+
 def get_conductor_dir(project_path: Optional[str] = None) -> Path:
- """
- [C: tests/test_paths.py:test_conductor_dir_project_relative, tests/test_project_paths.py:test_get_conductor_dir_default, tests/test_project_paths.py:test_get_conductor_dir_project_specific_with_toml]
- """
+ """[C: tests/test_paths.py:test_conductor_dir_project_relative, tests/test_project_paths.py:test_get_conductor_dir_default, tests/test_project_paths.py:test_get_conductor_dir_project_specific_with_toml]"""
  if not project_path:
-  # Fallback for legacy/tests, but we should avoid this
   return Path('conductor').resolve()
- 
  project_root = Path(project_path).resolve()
- p            = _get_project_conductor_dir_from_toml(project_root)
+ p = _get_project_conductor_dir_from_toml(project_root)
  if p: return p
  return (project_root / "conductor").resolve()
 
-def get_logs_dir() -> Path:
- """
- [C: src/session_logger.py:close_session, src/session_logger.py:open_session, tests/test_paths.py:test_config_overrides, tests/test_paths.py:test_default_paths, tests/test_paths.py:test_env_var_overrides, tests/test_paths.py:test_precedence]
- """
- if "logs_dir" not in _RESOLVED:
-  _RESOLVED["logs_dir"] = _resolve_path("SLOP_LOGS_DIR", "logs_dir", "logs/sessions")
- return _RESOLVED["logs_dir"]
-
-def get_scripts_dir() -> Path:
- """
- [C: src/session_logger.py:log_tool_call, src/session_logger.py:open_session, tests/test_paths.py:test_config_overrides, tests/test_paths.py:test_default_paths]
- """
- if "scripts_dir" not in _RESOLVED:
-  _RESOLVED["scripts_dir"] = _resolve_path("SLOP_SCRIPTS_DIR", "scripts_dir", "scripts/generated")
- return _RESOLVED["scripts_dir"]
-
-def get_tracks_dir(project_path: Optional[str] = None) -> Path:
- """
- [C: src/project_manager.py:get_all_tracks, tests/test_paths.py:test_conductor_dir_project_relative]
- """
- return get_conductor_dir(project_path) / "tracks"
-
-def get_track_state_dir(track_id: str, project_path: Optional[str] = None) -> Path:
- """
- [C: src/project_manager.py:load_track_state, src/project_manager.py:save_track_state, tests/test_paths.py:test_conductor_dir_project_relative]
- """
- return get_tracks_dir(project_path) / track_id
-
-def get_archive_dir(project_path: Optional[str] = None) -> Path:
- """
- [C: tests/test_paths.py:test_conductor_dir_project_relative]
- """
- return get_conductor_dir(project_path) / "archive"
-
-def _resolve_path_info(env_var: str, config_key: str, default: str) -> dict[str, Any]:
- if env_var in os.environ:
-  return {'path': Path(os.environ[env_var]).resolve(), 'source': f'env:{env_var}'}
- try:
-  with open(get_config_path(), 'rb') as f:
-   cfg = tomllib.load(f)
-  if 'paths' in cfg and config_key in cfg['paths']:
-   p = Path(cfg['paths'][config_key])
-   if not p.is_absolute():
-    p = (Path(__file__).resolve().parent.parent / p).resolve()
-   return {'path': p, 'source': 'config.toml'}
- except: pass
- root_dir = Path(__file__).resolve().parent.parent
- p = (root_dir / default).resolve()
- return {'path': p, 'source': 'default'}
 
 def get_full_path_info() -> dict[str, dict[str, Any]]:
+ """Return the resolved paths + their source (env / config / default).
+ For diagnostic UIs (e.g., the Session Hub's "show resolved paths" panel).
+ [C: src/gui_2.py:App._render_path_field]"""
+ cfg = _cfg()
+ def info(value: Path) -> dict[str, Any]:
+  return {'path': str(value), 'source': 'frozen_at_init'}
  return {
-  'logs_dir': _resolve_path_info('SLOP_LOGS_DIR', 'logs_dir', 'logs/sessions'),
-  'scripts_dir': _resolve_path_info('SLOP_SCRIPTS_DIR', 'scripts_dir', 'scripts/generated')
+  'config_path':        info(cfg.config_path),
+  'presets':            info(cfg.presets),
+  'tool_presets':       info(cfg.tool_presets),
+  'personas':           info(cfg.personas),
+  'themes':             info(cfg.themes),
+  'workspace_profiles': info(cfg.workspace_profiles),
+  'credentials':        info(cfg.credentials),
+  'logs_dir':           info(cfg.logs_dir),
+  'scripts_dir':        info(cfg.scripts_dir),
  }
 
-def reset_resolved() -> None:
- """
- For testing only - clear cached resolutions.
- [C: tests/conftest.py:reset_paths, tests/test_app_controller_offloading.py:tmp_session_dir, tests/test_gui_phase3.py:test_conductor_setup_scan, tests/test_paths.py:reset_paths, tests/test_project_paths.py:test_get_all_tracks_project_specific, tests/test_project_paths.py:test_get_conductor_dir_default, tests/test_project_paths.py:test_get_conductor_dir_project_specific_with_toml]
- """
- _RESOLVED.clear()
- 
\ No newline at end of file
+
+def reset_paths() -> None:
+ """Clear the singleton. FOR TESTS ONLY — production code should never
+ call this. After reset, the next path getter raises RuntimeError until
+ initialize_paths() is called again.
+ [C: tests/conftest.py:reset_paths, tests/test_paths.py:reset_paths,
+    tests/test_app_controller_offloading.py:setup_function,
+    tests/test_gui_phase3.py:setup]"""
+ global _PATHS_CONFIG
+ with _PATHS_LOCK:
+  _PATHS_CONFIG = None
\ No newline at end of file
diff --git a/tests/conftest.py b/tests/conftest.py
index 75e622fc..45b0a157 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -34,7 +34,7 @@ if _config_override_arg is None:
  _config_override_arg = _ISOLATION_WORKSPACE / "config_overrides.toml"
 
 from src import paths as _paths  # noqa: E402
-_paths.set_config_override(_config_override_arg)
+_paths.initialize_paths(_config_override_arg)
 
 thirdparty_dir = os.path.join(os.path.dirname(__file__), "..", "thirdparty")
 if thirdparty_dir not in sys.path:
@@ -381,11 +381,11 @@ def isolate_workspace(monkeypatch) -> Generator[None, None, None]:
  (tests/artifacts/_isolation_workspace_<RUN_ID>/). Also writes placeholder
  TOML files for the redirected paths. NO SLOP_* env vars are set;
  src/paths.py reads the overrides from config.toml [paths] (with env var
- as fallback if needed).
- [C: tests/conftest.py:_ISOLATION_WORKSPACE, src/paths.py:_resolve_path]
+ as fallback if needed). Also re-initializes the paths singleton so every
+ getter sees the test-workspace overrides.
+ [C: tests/conftest.py:_ISOLATION_WORKSPACE, src/paths.py:initialize_paths]
  """
  from src import paths as _paths
- _paths.reset_resolved()
 
  test_workspace = _ISOLATION_WORKSPACE
 
@@ -421,14 +421,15 @@ def isolate_workspace(monkeypatch) -> Generator[None, None, None]:
 @pytest.fixture(autouse=True)
 def reset_paths() -> Generator[None, None, None]:
  """
- 
-  
-   Autouse fixture that resets the paths global state before each test.
+ Autouse fixture that resets the paths singleton before each test.
+ The isolate_workspace fixture re-initializes paths before the test runs,
+ so reset_paths is a no-op here (PathsConfig is frozen at init time,
+ the per-getter cache is gone). Kept as a marker for backward compatibility
+ with test code that asserts the singleton is cleared at test boundaries.
  """
  from src import paths
- paths.reset_resolved()
  yield
- paths.reset_resolved()
+ paths.reset_paths()
 
 @pytest.fixture(autouse=True)
 def reset_ai_client() -> Generator[None, None, None]:
diff --git a/tests/test_app_controller_offloading.py b/tests/test_app_controller_offloading.py
index cdee541a..bddd2961 100644
--- a/tests/test_app_controller_offloading.py
+++ b/tests/test_app_controller_offloading.py
@@ -18,7 +18,7 @@ def tmp_session_dir(tmp_path, monkeypatch):
  
  monkeypatch.setenv("SLOP_LOGS_DIR", str(logs_dir))
  monkeypatch.setenv("SLOP_SCRIPTS_DIR", str(scripts_dir))
- paths.reset_resolved()
+ paths.reset_paths()
  
  # Ensure session_logger is clean
  with patch("src.session_logger._comms_fh", None):
diff --git a/tests/test_gui_paths.py b/tests/test_gui_paths.py
index 70817a7c..12240846 100644
--- a/tests/test_gui_paths.py
+++ b/tests/test_gui_paths.py
@@ -26,7 +26,7 @@ def test_save_paths():
  
  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('src.paths.reset_paths') as mock_reset, \
       patch.object(MockApp, 'init_state') as mock_init:
   
   mock_get_cfg.return_value = MagicMock()
diff --git a/tests/test_gui_phase3.py b/tests/test_gui_phase3.py
index 3b3b1d83..aa38d38f 100644
--- a/tests/test_gui_phase3.py
+++ b/tests/test_gui_phase3.py
@@ -50,7 +50,7 @@ def test_conductor_setup_scan(app_instance, tmp_path, monkeypatch):
   (cond_dir / "tracks" / "track1").mkdir(exist_ok=True)
   
   monkeypatch.setenv('SLOP_CONDUCTOR_DIR', str((tmp_path / 'conductor').resolve()))
-  paths.reset_resolved()
+  paths.reset_paths()
   
   app_instance._cb_run_conductor_setup()
   
diff --git a/tests/test_paths.py b/tests/test_paths.py
index 7c526a81..6ec7ce27 100644
--- a/tests/test_paths.py
+++ b/tests/test_paths.py
@@ -5,9 +5,9 @@ from src import paths
 
 @pytest.fixture(autouse=True)
 def reset_paths():
- paths.reset_resolved()
+ paths.reset_paths()
  yield
- paths.reset_resolved()
+ paths.reset_paths()
 
 def test_default_paths(tmp_path, monkeypatch):
  monkeypatch.setenv("SLOP_CONFIG", str(tmp_path / "non_existent.toml"))
diff --git a/tests/test_project_paths.py b/tests/test_project_paths.py
index 0adc4fe9..629b8435 100644
--- a/tests/test_project_paths.py
+++ b/tests/test_project_paths.py
@@ -7,13 +7,13 @@ from src import paths
 from src import project_manager
 
 def test_get_conductor_dir_default():
- paths.reset_resolved()
+ paths.reset_paths()
  # Should return absolute path to "conductor" in project root
  expected = Path(__file__).resolve().parent.parent / "conductor"
  assert paths.get_conductor_dir() == expected
 
 def test_get_conductor_dir_project_specific_with_toml(tmp_path):
- paths.reset_resolved()
+ paths.reset_paths()
  project_root = tmp_path / "my_project"
  project_root.mkdir()
  
@@ -31,7 +31,7 @@ def test_get_conductor_dir_project_specific_with_toml(tmp_path):
  assert res == project_root / "custom_tracks"
 
 def test_get_all_tracks_project_specific(tmp_path):
- paths.reset_resolved()
+ paths.reset_paths()
  project_root = tmp_path / "my_project"
  project_root.mkdir()
  
diff --git a/tests/test_test_sandbox.py b/tests/test_test_sandbox.py
index 7f4a475d..bc6cca6c 100644
--- a/tests/test_test_sandbox.py
+++ b/tests/test_test_sandbox.py
@@ -149,47 +149,64 @@ def test_sandbox_allows_pytest_cache_write() -> None:
 
 
 def test_config_override_via_cli_flag(tmp_path) -> None:
- """paths.set_config_override(path) makes get_config_path() return that path."""
+ """paths.initialize_paths(config_path) makes all path getters return paths
+ rooted at config_path's [paths] section (or default).
+ [C: src/paths.py:initialize_paths, sloppy.py:main]"""
  from src import paths
  config_path = tmp_path / "my_config.toml"
  config_path.write_text("[ai]\nprovider='gemini'\n", encoding="utf-8")
- original = paths._CONFIG_OVERRIDE
+ paths.initialize_paths(config_path)
  try:
-  paths.set_config_override(config_path)
   assert paths.get_config_path() == config_path
+  assert paths.get_global_presets_path().name == "presets.toml"
+  assert paths.get_logs_dir().name == "sessions"
  finally:
-  paths.set_config_override(original)
+  paths.reset_paths()
 
 
-def test_paths_get_config_path_no_env_fallback(monkeypatch) -> None:
- """Without an override AND without SLOP_CONFIG, get_config_path returns default."""
- monkeypatch.delenv("SLOP_CONFIG", raising=False)
+def test_paths_runtime_refresh_atomic_swap(tmp_path) -> None:
+ """Calling initialize_paths() a second time atomically swaps the singleton.
+ Reader threads see the new config immediately. The PathsConfig is frozen.
+ [C: src/paths.py:initialize_paths, src/paths.py:PathsConfig]"""
  from src import paths
- original = paths._CONFIG_OVERRIDE
- try:
-  paths.set_config_override(None)
-  expected = Path(__file__).resolve().parent.parent / "config.toml"
-  assert paths.get_config_path() == expected
- finally:
-  paths.set_config_override(original)
+ cfg_a = tmp_path / "a.toml"
+ cfg_b = tmp_path / "b.toml"
+ cfg_a.write_text("[ai]\nprovider='gemini-a'\n", encoding="utf-8")
+ cfg_b.write_text("[ai]\nprovider='gemini-b'\n", encoding="utf-8")
+ paths.initialize_paths(cfg_a)
+ assert paths.get_config_path() == cfg_a
+ paths.initialize_paths(cfg_b)
+ assert paths.get_config_path() == cfg_b
+ paths.reset_paths()
+
+
+def test_paths_uninitialized_raises(tmp_path) -> None:
+ """Calling a path getter before initialize_paths() raises RuntimeError
+ (not silent fallback). This is the contract that enforces explicit init.
+ [C: src/paths.py:_cfg]"""
+ from src import paths
+ paths.reset_paths()
+ with pytest.raises(RuntimeError, match="not initialized"):
+  paths.get_logs_dir()
+ paths.reset_paths()
 
 
 def test_sloppy_py_parses_config_flag() -> None:
- """sloppy.py has a --config argparse argument that calls set_config_override."""
+ """sloppy.py has a --config argparse argument that calls initialize_paths."""
  import ast
  sloppy = Path(__file__).resolve().parent.parent / "sloppy.py"
  tree = ast.parse(sloppy.read_text(encoding="utf-8"))
  found_config_arg = False
- found_set_override_call = False
+ found_init_call = False
  for node in ast.walk(tree):
   if isinstance(node, ast.Constant) and node.value == "--config":
    found_config_arg = True
   if isinstance(node, ast.Call):
    func = node.func
-   if isinstance(func, ast.Name) and func.id == "set_config_override":
-    found_set_override_call = True
+   if isinstance(func, ast.Name) and func.id == "initialize_paths":
+    found_init_call = True
  assert found_config_arg, "sloppy.py must have a --config argparse argument"
- assert found_set_override_call, "sloppy.py must call paths.set_config_override(args.config)"
+ assert found_init_call, "sloppy.py must call paths.initialize_paths(args.config)"
 
 
 def test_pyproject_toml_basetemp_is_under_tests() -> None:
@@ -276,30 +293,86 @@ def test_config_overrides_toml_has_paths_section() -> None:
   )
 
 
-def test_path_getters_read_from_config_paths_section() -> None:
- """Every global path getter in src/paths.py reads from the [paths] section
- of the active config when no env var is set. Verifies via AST that each
- get_*_path() function calls _resolve_path (not raw os.environ.get)."""
+def test_path_getters_are_trivial_field_access() -> None:
+ """Every global path getter in src/paths.py is a trivial field access on the
+ PathsConfig singleton (return _cfg().<field>). They must NOT do file I/O
+ or call _resolve_path() (which is internal-only, called from initialize_paths).
+ This enforces the v3 design: explicit init at startup, trivial getters."""
  import ast
  paths_py = Path(__file__).resolve().parent.parent / "src" / "paths.py"
  tree = ast.parse(paths_py.read_text(encoding="utf-8"))
- getters = {
-  "get_global_presets_path": "presets",
-  "get_global_tool_presets_path": "tool_presets",
-  "get_global_personas_path": "personas",
-  "get_global_themes_path": "themes",
-  "get_global_workspace_profiles_path": "workspace_profiles",
-  "get_credentials_path": "credentials",
-  "get_logs_dir": "logs_dir",
-  "get_scripts_dir": "scripts_dir",
- }
+ trivial_getters = [
+  "get_global_presets_path", "get_global_tool_presets_path",
+  "get_global_personas_path", "get_global_themes_path",
+  "get_global_workspace_profiles_path", "get_credentials_path",
+  "get_logs_dir", "get_scripts_dir",
+ ]
  for node in ast.walk(tree):
-  if isinstance(node, ast.FunctionDef) and node.name in getters:
+  if isinstance(node, ast.FunctionDef) and node.name in trivial_getters:
    src = ast.unparse(node)
-   assert "_resolve_path(" in src, (
-    f"{node.name} must call _resolve_path() to read from config.toml [paths]; "
-    f"got direct os.environ.get() instead."
+   assert "_cfg()" in src, (
+    f"{node.name} must call _cfg() to read from the PathsConfig singleton; "
+    f"got direct file I/O or env var lookup instead."
    )
+   assert "_resolve_path(" not in src, (
+    f"{node.name} must NOT call _resolve_path(); that's internal-only "
+    f"(called once from initialize_paths)."
+   )
+   assert "os.environ" not in src, (
+    f"{node.name} must NOT use os.environ directly; env vars are read once "
+    f"during initialize_paths()."
+   )
+
+
+def test_initialize_paths_thread_safe_atomic_swap(tmp_path) -> None:
+ """initialize_paths() uses an RLock; concurrent swaps don't corrupt the
+ singleton. Reader threads always see a consistent PathsConfig snapshot
+ (frozen dataclass). Per the user's "bad programmers take shortcuts" rule:
+ no torn writes, no partial reads.
+ [C: src/paths.py:_PATHS_LOCK, src/paths.py:PathsConfig]"""
+ import threading
+ import tomllib
+ from src import paths
+ cfg_a = tmp_path / "a.toml"
+ cfg_b = tmp_path / "b.toml"
+ cfg_a.write_bytes(b"[paths]\nlogs_dir = 'C:/tmp/thread_a'\n")
+ cfg_b.write_bytes(b"[paths]\nlogs_dir = 'C:/tmp/thread_b'\n")
+ errors = []
+ def swap(cfg, n):
+  for _ in range(n):
+   try:
+    paths.initialize_paths(cfg)
+   except Exception as e:
+    errors.append(e)
+ t1 = threading.Thread(target=swap, args=(cfg_a, 100))
+ t2 = threading.Thread(target=swap, args=(cfg_b, 100))
+ t1.start(); t2.start()
+ t1.join(); t2.join()
+ assert not errors, f"thread-safety violation: {errors}"
+ paths.reset_paths()
+
+
+def test_pathsconfig_is_frozen_dataclass() -> None:
+ """PathsConfig uses @dataclass(frozen=True) so individual field reads are
+ atomic and cannot be mutated by readers. Per user directive: gated
+ transactions, no data race over config.
+ [C: src/paths.py:PathsConfig]"""
+ import dataclasses
+ import tempfile, tomli_w
+ from src import paths
+ params = getattr(paths.PathsConfig, "__dataclass_params__", None)
+ assert params is not None, "PathsConfig must be a dataclass"
+ assert params.frozen is True, "PathsConfig must be @dataclass(frozen=True)"
+ with tempfile.NamedTemporaryFile(suffix=".toml", delete=False, mode="wb") as f:
+  tomli_w.dump({"paths": {"logs_dir": "C:/tmp/frozen_test"}}, f)
+  cfg = Path(f.name)
+ try:
+  paths.initialize_paths(cfg)
+  with pytest.raises(dataclasses.FrozenInstanceError):
+   paths._PATHS_CONFIG.presets = Path("/tmp/should_fail")
+ finally:
+  paths.reset_paths()
+  cfg.unlink()
 
 
 @pytest.mark.skipif(os.name != "nt", reason="Windows-only sandbox wrapper")