diff --git a/docker-compose.yml b/docker-compose.yml
index bac125c93f..910392b25c 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -14,6 +14,9 @@
 #     keys; exposing it on LAN without auth is unsafe. If you want remote
 #     access, use an SSH tunnel or put it behind a reverse proxy that
 #     adds authentication — do NOT pass --insecure --host 0.0.0.0.
+#   - If you override entrypoint, keep /opt/hermes/docker/entrypoint.sh in
+#     the command chain. It drops root to the hermes user before gateway
+#     files such as gateway.lock are created.
 #   - The gateway's API server is off unless you uncomment API_SERVER_KEY
 #     and API_SERVER_HOST. See docs/user-guide/api-server.md before doing
 #     this on an internet-facing host.
diff --git a/hermes_cli/gateway.py b/hermes_cli/gateway.py
index 9dc34b9d78..5f95d0c204 100644
--- a/hermes_cli/gateway.py
+++ b/hermes_cli/gateway.py
@@ -2770,6 +2770,42 @@ def launchd_status(deep: bool = False):
 # Gateway Runner
 # =============================================================================
 
+def _truthy_env(value: str | None) -> bool:
+    return str(value or "").strip().lower() in {"1", "true", "yes", "on"}
+
+
+def _is_official_docker_checkout() -> bool:
+    return (
+        str(PROJECT_ROOT) == "/opt/hermes"
+        and (PROJECT_ROOT / "docker" / "entrypoint.sh").is_file()
+    )
+
+
+def _guard_official_docker_root_gateway() -> None:
+    """Refuse gateway startup when the official Docker privilege drop was bypassed."""
+    if not hasattr(os, "geteuid") or os.geteuid() != 0:
+        return
+    if _truthy_env(os.getenv("HERMES_ALLOW_ROOT_GATEWAY")):
+        return
+    if not _is_official_docker_checkout():
+        return
+
+    print_error(
+        "Refusing to run the Hermes gateway as root inside the official Docker image."
+    )
+    print(
+        "  The image entrypoint normally drops privileges to the 'hermes' user. "
+        "If you override entrypoint in Docker Compose, include "
+        "/opt/hermes/docker/entrypoint.sh before the Hermes command."
+    )
+    print(
+        "  Running the gateway as root can leave root-owned files in "
+        "$HERMES_HOME and break later non-root dashboard/gateway runs."
+    )
+    print("  Set HERMES_ALLOW_ROOT_GATEWAY=1 only if you intentionally accept this risk.")
+    sys.exit(1)
+
+
 def run_gateway(verbose: int = 0, quiet: bool = False, replace: bool = False):
     """Run the gateway in foreground.
     
@@ -2780,6 +2816,7 @@ def run_gateway(verbose: int = 0, quiet: bool = False, replace: bool = False):
                  This prevents systemd restart loops when the old process
                  hasn't fully exited yet.
     """
+    _guard_official_docker_root_gateway()
     sys.path.insert(0, str(PROJECT_ROOT))
 
     # Refresh the systemd unit definition on every boot so that restart
diff --git a/tests/hermes_cli/test_gateway.py b/tests/hermes_cli/test_gateway.py
index 6dfbd636f4..9d16ad10a7 100644
--- a/tests/hermes_cli/test_gateway.py
+++ b/tests/hermes_cli/test_gateway.py
@@ -53,6 +53,43 @@ def test_run_gateway_exits_nonzero_when_start_gateway_reports_failure(monkeypatc
     assert calls == [(True, None)]
 
 
+def test_run_gateway_refuses_root_in_official_docker(monkeypatch, tmp_path, capsys):
+    project_root = tmp_path / "opt" / "hermes"
+    (project_root / "docker").mkdir(parents=True)
+    (project_root / "docker" / "entrypoint.sh").write_text("#!/bin/sh\n")
+
+    monkeypatch.setattr(gateway, "PROJECT_ROOT", project_root)
+    monkeypatch.setattr(gateway.os, "geteuid", lambda: 0)
+    monkeypatch.delenv("HERMES_ALLOW_ROOT_GATEWAY", raising=False)
+    monkeypatch.setattr(gateway, "_is_official_docker_checkout", lambda: True)
+
+    with pytest.raises(SystemExit) as exc_info:
+        gateway.run_gateway()
+
+    assert exc_info.value.code == 1
+    out = capsys.readouterr().out
+    assert "Refusing to run the Hermes gateway as root" in out
+    assert "/opt/hermes/docker/entrypoint.sh" in out
+
+
+def test_run_gateway_root_guard_has_escape_hatch(monkeypatch):
+    calls = []
+
+    def fake_start_gateway(*, replace, verbosity):
+        calls.append((replace, verbosity))
+        return object()
+
+    _install_fake_gateway_run(monkeypatch, fake_start_gateway)
+    monkeypatch.setattr(gateway.asyncio, "run", lambda coro: True)
+    monkeypatch.setattr(gateway.os, "geteuid", lambda: 0)
+    monkeypatch.setattr(gateway, "_is_official_docker_checkout", lambda: True)
+    monkeypatch.setenv("HERMES_ALLOW_ROOT_GATEWAY", "1")
+
+    gateway.run_gateway(verbose=2, replace=True)
+
+    assert calls == [(True, 2)]
+
+
 class TestSystemdLingerStatus:
     def test_reports_enabled(self, monkeypatch):
         monkeypatch.setattr(gateway, "is_linux", lambda: True)
diff --git a/website/docs/user-guide/docker.md b/website/docs/user-guide/docker.md
index bf4b4e9b68..2c1c7dde4e 100644
--- a/website/docs/user-guide/docker.md
+++ b/website/docs/user-guide/docker.md
@@ -271,6 +271,10 @@ The entrypoint script (`docker/entrypoint.sh`) bootstraps the data volume on fir
 - Optionally launches `hermes dashboard` as a background side-process when `HERMES_DASHBOARD=1` (see [Running the dashboard](#running-the-dashboard))
 - Then runs `hermes` with whatever arguments you pass
 
+:::warning
+Do not override the image entrypoint unless you keep `/opt/hermes/docker/entrypoint.sh` in the command chain. The entrypoint drops root privileges to the `hermes` user before gateway state files are created. Starting `hermes gateway run` as root inside the official image is refused by default because it can leave root-owned files in `/opt/data` and break later dashboard or gateway starts. Set `HERMES_ALLOW_ROOT_GATEWAY=1` only when you intentionally accept that risk.
+:::
+
 ## Upgrading
 
 Pull the latest image and recreate the container. Your data directory is untouched.