diff --git a/docs/swarm/sso.md b/docs/swarm/sso.md
index fe17e5b8..cb38d00a 100644
--- a/docs/swarm/sso.md
+++ b/docs/swarm/sso.md
@@ -242,11 +242,18 @@ page-only check. This was verified that way when the split was introduced.
 
 ## What this doesn't do
 
-- **It doesn't disable local login.** Each service keeps its password
-  database and gains a second door. An identity provider that can take a
-  service offline when it hiccups is worse than one with two ways in.
-  Making authelia the only path is a separate, reversible switch per
-  service (tuwunel's `login_with_password`, forgejo's own setting).
+- **It doesn't disable local login — except on Grafana.** Forgejo and
+  tuwunel keep their password databases and gain a second door: an identity
+  provider that can take a service offline when it hiccups is worse than one
+  with two ways in, and making authelia the only path there is a separate,
+  reversible switch (tuwunel's `login_with_password`, forgejo's own setting).
+  ⚠️ **Grafana is the exception, and not a reversible one.** Its module sets
+  `auth.disable_login_form` unconditionally, because Grafana ships an
+  `admin`/`admin` account and its vhost is on the public gateway — so a
+  password box there is a way in whatever the deployment. SSO is the only
+  door, and a dead provider locks everyone out, the built-in admin
+  included. That's why `swarm.grafana.oidc.role` defaults to `Admin`; see
+  [`services.md`](services.md#metrics-victoriametrics--grafana).
 - **It doesn't provision users.** Agents are created and destroyed
   continuously, so the subject set belongs to a program rather than to a
   config file; today that program is `swarmctl`.
diff --git a/nix/host-modules/swarm-grafana.nix b/nix/host-modules/swarm-grafana.nix
index bbc68473..81ec4374 100644
--- a/nix/host-modules/swarm-grafana.nix
+++ b/nix/host-modules/swarm-grafana.nix
@@ -701,10 +701,17 @@ in
               # whole host fails to build. The unit below generates it.
               security.secret_key = "$__file{${secretKeyPath}}";
 
-              # No local password path at all when SSO is configured. This
-              # is not tidiness: Grafana ships an `admin`/`admin` account,
-              # and this vhost is on the public gateway.
-              auth.disable_login_form = ssoLocal;
+              # No local password path, ever. This is not tidiness: Grafana
+              # ships an `admin`/`admin` account and this vhost is on the
+              # public gateway, so SSO is the only way in — not merely the
+              # preferred one.
+              #
+              # Deliberately NOT `ssoLocal`: whether a password box sits on a
+              # public login page cannot depend on which host happens to run
+              # authelia. The OIDC block below is still gated on locality;
+              # making that follow the same swarm-wide question is a larger
+              # change tracked on its own.
+              auth.disable_login_form = true;
             }
             // lib.optionalAttrs ssoLocal {
               "auth.generic_oauth" = {
diff --git a/nix/module-eval.nix b/nix/module-eval.nix
index 839365b0..74b04cc9 100644
--- a/nix/module-eval.nix
+++ b/nix/module-eval.nix
@@ -655,6 +655,16 @@ let
         rule: lib.hasInfix "/run/test-grafana-sock" rule
       ) grafanaOldPath.systemd.tmpfiles.rules;
     }
+    {
+      # This fixture enables grafana and NOT authelia, which is the shape the
+      # login form used to stay enabled in: the toggle read "both services are
+      # on this host" rather than "grafana requires SSO". Grafana ships an
+      # `admin`/`admin` account and its vhost is on the public gateway, so a
+      # password box there is a way in whatever the topology.
+      name = "grafana disables its local login form even where authelia is not on this host";
+      ok =
+        grafanaOldPath.containers.swarm-grafana.config.services.grafana.settings.auth.disable_login_form;
+    }
     {
       # Reads the daemon's rendered unit, not the options: the queue address
       # arrives as an env var whose whole attrset is guarded on `natsUrl`, and