@@ -278,6 +278,39 @@ after one minute or a five-second blocked send. Each gateway process accepts at
 most 32 watches. Reconnect and relist on stream termination; revisions are opaque
 equality tokens, not resumable cursors or an ordering across gateway replicas.
 
+## Gateway application authentication
+
+Gateway-mediated application HTTP requests and WebSocket upgrades authenticate
+through the gateway chain or verified TLS client identity before endpoint lookup,
+independently of app-listener enablement. User access requires TCP-forwarding
+role/scope policy (`sandbox:write` when enforced) and current workspace membership;
+operators retain their platform grant. Internal principals are rejected. Only
+explicit local-development unauthenticated access bypasses this gate.
+
+`/auth/services` hosts browser login on the control-plane origin. The application
+origin receives a single-use bootstrap code bound to a browser login nonce, then
+a distinct host-only, Secure/HttpOnly session cookie. Shared metadata contains
+only credential-driver handles and hashes; the configured credential driver
+stores the access token. Login codes expire after two minutes, sessions after
+at most ten minutes or token expiry. Every request revalidates the token and
+workspace authorization. Session deletion, credential revocation, and redemption
+CAS use the shared database. Expired metadata cleanup and admission are bounded.
+The application path consumes standard gateway bearer headers, or authenticates
+through a separate `X-OpenShell-Authorization`, browser session, or mTLS identity
+while preserving application bearer passthrough and cookies. Gateway headers and
+reserved cookies never reach the workload, and workloads cannot set reserved
+browser auth cookies. Browser ambient credentials require origin checks for
+unsafe methods and WebSocket upgrades. Direct supervisor ingress delegates
+application authentication to its ingress provider.
+
+The optional real-Chrome login test uses an isolated profile and local test
+credentials. Run it with `OPENSHELL_BROWSER_E2E_CHROME` pointing to Chrome:
+
+```shell
+OPENSHELL_BROWSER_E2E_CHROME='/Applications/Google Chrome.app/Contents/MacOS/Google Chrome' \
+  cargo test -p openshell-server --lib gateway_service_auth_real_browser_cross_site_login -- --ignored
+```
+
 ## Application URL publication
 
 `supervisor.app_listener.public_url` is an optional HTTPS origin matching the
 
@@ -57,6 +57,10 @@ struct ConnectParams {
 /// Create the auth router.
 pub fn router(state: Arc<ServerState>) -> Router {
     Router::new()
+        .route(
+            "/auth/services",
+            get(service_browser_login).post(service_browser_login),
+        )
         .route("/auth/connect", get(auth_connect))
         .route("/auth/oidc-config", get(oidc_config_handler))
         .route("/.well-known/jwks.json", get(gateway_jwks_handler))
@@ -67,6 +71,16 @@ pub fn router(state: Arc<ServerState>) -> Router {
         .with_state(state)
 }
 
+async fn service_browser_login(
+    State(state): State<Arc<ServerState>>,
+    req: axum::extract::Request,
+) -> axum::response::Response {
+    match super::service_session::control(&state, req).await {
+        Ok(response) => response,
+        Err(error) => super::service_session::error(&error),
+    }
+}
+
 /// Publish OIDC-shaped discovery metadata for extension services.
 ///
 /// This lets an extension be configured with only the trusted gateway URL:
 
@@ -25,6 +25,8 @@ pub mod principal;
 pub mod sandbox_jwt;
 pub mod sandbox_methods;
 pub mod sandbox_session;
+pub mod service_access;
+pub mod service_session;
 pub mod supervisor_token;
 pub mod workspace_authz;
 
 
@@ -948,7 +948,7 @@ impl Authenticator for OidcAuthenticator {
 }
 
 #[cfg(test)]
-mod tests {
+pub mod tests {
     use super::*;
 
     fn transport_test_config(issuer: impl Into<String>) -> OidcConfig {
@@ -1418,7 +1418,7 @@ mod tests {
     }
 
     /// Sign `claims` with the test key, tagging the header with `kid`.
-    fn mint_rs256(claims: &serde_json::Value, kid: &str) -> String {
+    pub fn mint_rs256(claims: &serde_json::Value, kid: &str) -> String {
         crate::install_jsonwebtoken_crypto_provider();
 
         let mut header = jsonwebtoken::Header::new(Algorithm::RS256);
@@ -1428,7 +1428,7 @@ mod tests {
         openshell_crypto::jwt::encode(&header, claims, &key).expect("sign RS256 token")
     }
 
-    fn claims_for(issuer: &str, audience: &str, exp: i64) -> serde_json::Value {
+    pub fn claims_for(issuer: &str, audience: &str, exp: i64) -> serde_json::Value {
         serde_json::json!({
             "sub": "user-42",
             "preferred_username": "ada",
@@ -1442,7 +1442,7 @@ mod tests {
 
     /// Serve an OIDC discovery document and a JWKS carrying the test key, then
     /// build a cache against them the same way production does.
-    async fn cache_with_mock_issuer(server: &wiremock::MockServer) -> JwksCache {
+    pub async fn cache_with_mock_issuer(server: &wiremock::MockServer) -> JwksCache {
         use wiremock::matchers::{method, path};
         use wiremock::{Mock, ResponseTemplate};