diff --git a/l4d2web/routes/overlay_routes.py b/l4d2web/routes/overlay_routes.py
index 012971e..6a8ac5f 100644
--- a/l4d2web/routes/overlay_routes.py
+++ b/l4d2web/routes/overlay_routes.py
@@ -7,7 +7,9 @@ from l4d2host.paths import get_left4me_root
 
 from l4d2web.auth import current_user, require_login
 from l4d2web.db import session_scope
-from l4d2web.models import BlueprintOverlay, Overlay
+from l4d2web.models import BlueprintOverlay, Job, Overlay
+from l4d2web.services import overlay_builders
+from l4d2web.services.job_worker import enqueue_build_overlay
 from l4d2web.services.overlay_creation import (
     create_overlay_directory,
     generate_overlay_path,
@@ -15,6 +17,7 @@ from l4d2web.services.overlay_creation import (
 
 
 CREATABLE_OVERLAY_TYPES = {"workshop", "script"}
+WIPE_SCRIPT = "find /overlay -mindepth 1 -delete"
 
 
 bp = Blueprint("overlay", __name__)
@@ -53,12 +56,13 @@ def create_overlay() -> Response:
 
     name = request.form.get("name", "").strip()
     overlay_type = request.form.get("type", "workshop").strip().lower()
+    system_wide = request.form.get("system_wide") == "1"
     if not name:
         return Response("missing fields", status=400)
     if overlay_type not in CREATABLE_OVERLAY_TYPES:
         return Response(f"unknown overlay type: {overlay_type}", status=400)
 
-    scope_user_id: int | None = user.id
+    scope_user_id: int | None = None if (system_wide and user.admin) else user.id
 
     with session_scope() as db:
         if _name_already_taken(db, name, scope_user_id):
@@ -123,3 +127,80 @@ def delete_overlay(overlay_id: int) -> Response:
             shutil.rmtree(target)
 
     return redirect("/overlays")
+
+
+def _load_script_overlay(db, overlay_id: int, user) -> tuple[Overlay | None, Response | None]:
+    overlay = db.scalar(select(Overlay).where(Overlay.id == overlay_id))
+    if overlay is None:
+        return None, Response(status=404)
+    if overlay.type != "script":
+        return None, Response("not a script overlay", status=400)
+    if not _can_edit_overlay(overlay, user):
+        return None, Response(status=403)
+    return overlay, None
+
+
+@bp.post("/overlays/<int:overlay_id>/script")
+@require_login
+def update_script(overlay_id: int) -> Response:
+    user = current_user()
+    assert user is not None
+    script_text = request.form.get("script", "")
+    with session_scope() as db:
+        overlay, err = _load_script_overlay(db, overlay_id, user)
+        if err is not None:
+            return err
+        overlay.script = script_text
+        enqueue_build_overlay(db, overlay_id=overlay_id, user_id=user.id)
+    return redirect(f"/overlays/{overlay_id}")
+
+
+@bp.post("/overlays/<int:overlay_id>/build")
+@require_login
+def manual_build(overlay_id: int) -> Response:
+    user = current_user()
+    assert user is not None
+    with session_scope() as db:
+        overlay = db.scalar(select(Overlay).where(Overlay.id == overlay_id))
+        if overlay is None:
+            return Response(status=404)
+        if not _can_edit_overlay(overlay, user):
+            return Response(status=403)
+        job = enqueue_build_overlay(db, overlay_id=overlay_id, user_id=user.id)
+        job_id = job.id
+    return redirect(f"/jobs/{job_id}")
+
+
+@bp.post("/overlays/<int:overlay_id>/wipe")
+@require_login
+def wipe_overlay(overlay_id: int) -> Response:
+    user = current_user()
+    assert user is not None
+    with session_scope() as db:
+        overlay, err = _load_script_overlay(db, overlay_id, user)
+        if err is not None:
+            return err
+        running = db.scalar(
+            select(Job).where(
+                Job.operation == "build_overlay",
+                Job.overlay_id == overlay_id,
+                Job.state.in_({"running", "cancelling"}),
+            )
+        )
+        if running is not None:
+            return Response("build in progress for this overlay", status=409)
+
+    overlay_builders.run_sandboxed_script(
+        overlay_id,
+        WIPE_SCRIPT,
+        on_stdout=lambda _line: None,
+        on_stderr=lambda _line: None,
+        should_cancel=lambda: False,
+    )
+
+    with session_scope() as db:
+        overlay = db.scalar(select(Overlay).where(Overlay.id == overlay_id))
+        if overlay is not None:
+            overlay.last_build_status = ""
+
+    return redirect(f"/overlays/{overlay_id}")
diff --git a/l4d2web/routes/workshop_routes.py b/l4d2web/routes/workshop_routes.py
index 7685a22..9b653a6 100644
--- a/l4d2web/routes/workshop_routes.py
+++ b/l4d2web/routes/workshop_routes.py
@@ -142,20 +142,6 @@ def remove_item(overlay_id: int, item_id: int) -> Response:
     return _render_item_table(overlay_id)
 
 
-@bp.post("/overlays/<int:overlay_id>/build")
-@require_login
-def manual_build(overlay_id: int) -> Response:
-    user = current_user()
-    assert user is not None
-    with session_scope() as db:
-        overlay, err = _check_workshop_overlay_access(overlay_id, user, db)
-        if err is not None:
-            return err
-        job = enqueue_build_overlay(db, overlay_id=overlay_id, user_id=user.id)
-        job_id = job.id
-    return redirect(f"/jobs/{job_id}")
-
-
 @bp.post("/admin/workshop/refresh")
 @require_admin
 def admin_refresh() -> Response:
diff --git a/l4d2web/tests/test_script_overlay_routes.py b/l4d2web/tests/test_script_overlay_routes.py
new file mode 100644
index 0000000..d54f361
--- /dev/null
+++ b/l4d2web/tests/test_script_overlay_routes.py
@@ -0,0 +1,256 @@
+"""Routes for type='script' overlays: create, /script (update body),
+/wipe, /build. Permissions mirror workshop overlays (owner or admin)."""
+from __future__ import annotations
+
+import pytest
+from sqlalchemy import select
+
+from l4d2web.app import create_app
+from l4d2web.auth import hash_password
+from l4d2web.db import init_db, session_scope
+from l4d2web.models import Job, Overlay, User
+
+
+@pytest.fixture
+def app(tmp_path, monkeypatch):
+    db_url = f"sqlite:///{tmp_path/'script-routes.db'}"
+    monkeypatch.setenv("DATABASE_URL", db_url)
+    monkeypatch.setenv("LEFT4ME_ROOT", str(tmp_path))
+    flask_app = create_app({"TESTING": True, "DATABASE_URL": db_url, "SECRET_KEY": "test"})
+    init_db()
+    return flask_app
+
+
+@pytest.fixture
+def alice_id(app) -> int:
+    with session_scope() as s:
+        user = User(username="alice", password_digest=hash_password("x"), admin=False)
+        s.add(user)
+        s.flush()
+        return user.id
+
+
+@pytest.fixture
+def bob_id(app) -> int:
+    with session_scope() as s:
+        user = User(username="bob", password_digest=hash_password("x"), admin=False)
+        s.add(user)
+        s.flush()
+        return user.id
+
+
+@pytest.fixture
+def admin_id(app) -> int:
+    with session_scope() as s:
+        user = User(username="admin", password_digest=hash_password("x"), admin=True)
+        s.add(user)
+        s.flush()
+        return user.id
+
+
+def _client_for(app, user_id: int):
+    client = app.test_client()
+    with client.session_transaction() as sess:
+        sess["user_id"] = user_id
+        sess["csrf_token"] = "test-token"
+    return client
+
+
+def _create_script_overlay(app, user_id: int, *, name: str = "x") -> int:
+    client = _client_for(app, user_id)
+    response = client.post(
+        "/overlays",
+        data={"name": name, "type": "script"},
+        headers={"X-CSRF-Token": "test-token"},
+    )
+    assert response.status_code == 302, response.get_data(as_text=True)
+    with session_scope() as s:
+        return s.scalar(select(Overlay.id).where(Overlay.name == name))
+
+
+def test_create_script_overlay(app, alice_id) -> None:
+    client = _client_for(app, alice_id)
+    response = client.post(
+        "/overlays",
+        data={"name": "first", "type": "script"},
+        headers={"X-CSRF-Token": "test-token"},
+    )
+    assert response.status_code == 302
+    with session_scope() as s:
+        overlay = s.query(Overlay).filter_by(name="first").one()
+        assert overlay.type == "script"
+        assert overlay.script == ""
+        assert overlay.last_build_status == ""
+        assert overlay.user_id == alice_id
+        assert overlay.path == str(overlay.id)
+
+
+def test_admin_creates_system_wide_script_overlay(app, admin_id) -> None:
+    client = _client_for(app, admin_id)
+    response = client.post(
+        "/overlays",
+        data={"name": "system", "type": "script", "system_wide": "1"},
+        headers={"X-CSRF-Token": "test-token"},
+    )
+    assert response.status_code == 302
+    with session_scope() as s:
+        overlay = s.query(Overlay).filter_by(name="system").one()
+        assert overlay.user_id is None
+
+
+def test_non_admin_system_wide_flag_is_ignored(app, alice_id) -> None:
+    client = _client_for(app, alice_id)
+    response = client.post(
+        "/overlays",
+        data={"name": "evil", "type": "script", "system_wide": "1"},
+        headers={"X-CSRF-Token": "test-token"},
+    )
+    assert response.status_code == 302
+    with session_scope() as s:
+        overlay = s.query(Overlay).filter_by(name="evil").one()
+        assert overlay.user_id == alice_id
+
+
+def test_update_script_body_enqueues_build(app, alice_id) -> None:
+    overlay_id = _create_script_overlay(app, alice_id)
+    client = _client_for(app, alice_id)
+
+    r1 = client.post(
+        f"/overlays/{overlay_id}/script",
+        data={"script": "echo new"},
+        headers={"X-CSRF-Token": "test-token"},
+    )
+    assert r1.status_code == 302
+    with session_scope() as s:
+        overlay = s.query(Overlay).filter_by(id=overlay_id).one()
+        assert overlay.script == "echo new"
+        jobs = s.query(Job).filter_by(operation="build_overlay", overlay_id=overlay_id).all()
+        assert len(jobs) == 1
+
+    # Coalesce against pending.
+    r2 = client.post(
+        f"/overlays/{overlay_id}/script",
+        data={"script": "echo newer"},
+        headers={"X-CSRF-Token": "test-token"},
+    )
+    assert r2.status_code == 302
+    with session_scope() as s:
+        jobs = s.query(Job).filter_by(operation="build_overlay", overlay_id=overlay_id).all()
+        assert len(jobs) == 1
+
+
+def test_manual_rebuild(app, alice_id) -> None:
+    overlay_id = _create_script_overlay(app, alice_id)
+    client = _client_for(app, alice_id)
+
+    r1 = client.post(
+        f"/overlays/{overlay_id}/build",
+        headers={"X-CSRF-Token": "test-token"},
+    )
+    assert r1.status_code == 302
+    with session_scope() as s:
+        jobs = s.query(Job).filter_by(operation="build_overlay", overlay_id=overlay_id).all()
+        assert len(jobs) == 1
+
+    # Coalesce.
+    r2 = client.post(
+        f"/overlays/{overlay_id}/build",
+        headers={"X-CSRF-Token": "test-token"},
+    )
+    assert r2.status_code == 302
+    with session_scope() as s:
+        jobs = s.query(Job).filter_by(operation="build_overlay", overlay_id=overlay_id).all()
+        assert len(jobs) == 1
+
+
+def test_wipe_runs_find_delete(app, alice_id, monkeypatch) -> None:
+    overlay_id = _create_script_overlay(app, alice_id)
+
+    # Pre-set a "successful" status so we can verify wipe resets it.
+    with session_scope() as s:
+        overlay = s.query(Overlay).filter_by(id=overlay_id).one()
+        overlay.last_build_status = "ok"
+
+    captured: dict = {}
+
+    def fake_run(overlay_id_arg, script_text, *, on_stdout, on_stderr, should_cancel):
+        captured["overlay_id"] = overlay_id_arg
+        captured["script"] = script_text
+
+    from l4d2web.services import overlay_builders
+    monkeypatch.setattr(overlay_builders, "run_sandboxed_script", fake_run)
+
+    client = _client_for(app, alice_id)
+    response = client.post(
+        f"/overlays/{overlay_id}/wipe",
+        headers={"X-CSRF-Token": "test-token"},
+    )
+    assert response.status_code == 302
+    assert captured["overlay_id"] == overlay_id
+    assert captured["script"] == "find /overlay -mindepth 1 -delete"
+
+    with session_scope() as s:
+        overlay = s.query(Overlay).filter_by(id=overlay_id).one()
+        assert overlay.last_build_status == ""
+        # Wipe does NOT auto-enqueue a rebuild.
+        jobs = s.query(Job).filter_by(operation="build_overlay", overlay_id=overlay_id).all()
+        assert len(jobs) == 0
+
+
+def test_wipe_refuses_during_running_build(app, alice_id, monkeypatch) -> None:
+    overlay_id = _create_script_overlay(app, alice_id)
+
+    # Mark a build as running for this overlay.
+    with session_scope() as s:
+        s.add(
+            Job(
+                user_id=alice_id,
+                server_id=None,
+                overlay_id=overlay_id,
+                operation="build_overlay",
+                state="running",
+            )
+        )
+
+    invocations: list = []
+
+    def fake_run(*args, **kwargs):
+        invocations.append((args, kwargs))
+
+    from l4d2web.services import overlay_builders
+    monkeypatch.setattr(overlay_builders, "run_sandboxed_script", fake_run)
+
+    client = _client_for(app, alice_id)
+    response = client.post(
+        f"/overlays/{overlay_id}/wipe",
+        headers={"X-CSRF-Token": "test-token"},
+    )
+    assert response.status_code == 409
+    assert invocations == []
+
+
+def test_permissions_non_owner_denied(app, alice_id, bob_id) -> None:
+    overlay_id = _create_script_overlay(app, alice_id, name="alice-private")
+    bob = _client_for(app, bob_id)
+
+    r1 = bob.post(
+        f"/overlays/{overlay_id}/script",
+        data={"script": "boom"},
+        headers={"X-CSRF-Token": "test-token"},
+    )
+    assert r1.status_code == 403
+
+
+def test_permissions_admin_can_edit_any(app, alice_id, admin_id) -> None:
+    overlay_id = _create_script_overlay(app, alice_id, name="alice-private")
+    admin = _client_for(app, admin_id)
+
+    r1 = admin.post(
+        f"/overlays/{overlay_id}/script",
+        data={"script": "echo admin"},
+        headers={"X-CSRF-Token": "test-token"},
+    )
+    assert r1.status_code == 302
+    with session_scope() as s:
+        overlay = s.query(Overlay).filter_by(id=overlay_id).one()
+        assert overlay.script == "echo admin"