diff --git a/docs/guides/operator-dashboard-sso.md b/docs/guides/operator-dashboard-sso.md
index cf2c9f2d..0a111234 100644
--- a/docs/guides/operator-dashboard-sso.md
+++ b/docs/guides/operator-dashboard-sso.md
@@ -11,9 +11,10 @@ public client). Distinct from the agent/callout machine auth
    secret), redirect URI `https://fleet-stg.<base>/auth/callback`, post-logout URI
    `https://fleet-stg.<base>/`. Copy its **Client ID**.
 1b. **Roles** — the dashboard requires the **`fleet-admin`** project role. Create that
-   role on the project, enable the project's **Assert Roles on Authentication** (so the
-   role lands in the ID token), and grant it to each operator user. Without it they
-   authenticate but get **403 Access denied**.
+   role on the project and grant it to each operator user. The login flow requests
+   roles **in-band** via the OIDC scope `urn:zitadel:iam:org:project:roles`, so the
+   project's **Assert Roles on Authentication** checkbox is **not** needed. Without
+   the role grant, users authenticate but get **403 Access denied**.
 2. **Seed config** in OpenBao (namespace `fleet-staging`) — the deploy derives every
    host from `base_domain`, so you set only:
    - `FleetDeployConfig.operator_oidc_client_id` = the Client ID
@@ -49,8 +50,9 @@ on the app's **Development Mode** (Zitadel rejects non-HTTPS redirects otherwise
 The operator reads `ZitadelAuthConfig` + `OperatorCookieKey` via ConfigClient. The
 deploy derives `zitadel_base` / `base_url` / `logout_redirect_uri` from `base_domain`
 (`https://sso-stg.<base>`, `https://fleet-stg.<base>`, `…/`) and fixes
-`scope = openid profile email`; you supply `client_id`, `trusted_audiences`,
-`cookie_key_b64`. All endpoints derive from `zitadel_base`:
+`scope = openid profile email` (the login flow appends
+`urn:zitadel:iam:org:project:roles` so roles are always asserted); you supply
+`client_id`, `trusted_audiences`, `cookie_key_b64`. All endpoints derive from `zitadel_base`:
 `/.well-known/openid-configuration`, `/oauth/v2/authorize`, `/oauth/v2/token`,
 `/oidc/v1/end_session`.
 
diff --git a/harmony_zitadel_auth/src/login.rs b/harmony_zitadel_auth/src/login.rs
index c92aae1b..8be81bef 100644
--- a/harmony_zitadel_auth/src/login.rs
+++ b/harmony_zitadel_auth/src/login.rs
@@ -134,6 +134,22 @@ pub fn build_logout_url(config: &ZitadelAuthConfig, id_token: &str) -> Result<Ur
     Ok(url)
 }
 
+/// Zitadel's reserved scope that asserts the caller's project roles in the
+/// token — the in-band alternative to the project's "Assert Roles on
+/// Authentication" checkbox, which is out-of-band and silently broke the gate.
+const ZITADEL_PROJECT_ROLES_SCOPE: &str = "urn:zitadel:iam:org:project:roles";
+
+fn ensure_roles_scope(scope: &str) -> String {
+    if scope
+        .split_whitespace()
+        .any(|s| s == ZITADEL_PROJECT_ROLES_SCOPE)
+    {
+        scope.to_string()
+    } else {
+        format!("{scope} {ZITADEL_PROJECT_ROLES_SCOPE}")
+    }
+}
+
 pub fn build_login_attempt(config: &ZitadelAuthConfig) -> Result<LoginAttempt> {
     let state = random_url_token(32);
     let pkce_code_verifier = random_url_token(32);
@@ -145,7 +161,7 @@ pub fn build_login_attempt(config: &ZitadelAuthConfig) -> Result<LoginAttempt> {
         .append_pair("client_id", &config.client_id)
         .append_pair("redirect_uri", &config.redirect_uri())
         .append_pair("response_type", "code")
-        .append_pair("scope", &config.scope)
+        .append_pair("scope", &ensure_roles_scope(&config.scope))
         .append_pair("code_challenge", &code_challenge)
         .append_pair("code_challenge_method", "S256")
         .append_pair("state", &state)
@@ -225,4 +241,18 @@ mod tests {
         let challenge = pkce_s256_challenge(code_verifier);
         assert_eq!(challenge, "E9Melhoa2OwvFrEMTJguCHaoeK1t8URWbuGJSstw-cM");
     }
+
+    #[test]
+    fn ensure_roles_scope_appends_when_absent() {
+        assert_eq!(
+            ensure_roles_scope("openid profile email"),
+            "openid profile email urn:zitadel:iam:org:project:roles"
+        );
+    }
+
+    #[test]
+    fn ensure_roles_scope_is_idempotent() {
+        let s = "openid urn:zitadel:iam:org:project:roles email";
+        assert_eq!(ensure_roles_scope(s), s);
+    }
 }