[core] az login: Broker Single Sign On

src/azure-cli-core/azure/cli/core/_profile.py

@@ -148,6 +148,7 @@ def login(self,
               is_service_principal,
               tenant,
               scopes=None,
+              use_broker_sso=False,
               use_device_code=False,
               allow_no_subscriptions=False,
               use_cert_sn_issuer=None,
@@ -176,7 +177,10 @@ def login(self,
             if use_device_code:
                 user_identity = identity.login_with_device_code(scopes=scopes, claims_challenge=claims_challenge)
             else:
-                user_identity = identity.login_with_auth_code(scopes=scopes, claims_challenge=claims_challenge)
+                user_identity = identity.login_with_auth_code(
+                    scopes=scopes,
+                    claims_challenge=claims_challenge,
+                    use_broker_sso=use_broker_sso)
         else:
             if not is_service_principal:
                 user_identity = identity.login_with_username_password(username, password, scopes=scopes)

src/azure-cli-core/azure/cli/core/auth/agentic_session.py

@@ -26,6 +26,11 @@
 COPILOT_AGENT_SESSION_ID = "COPILOT_AGENT_SESSION_ID"
 
 
+def is_agentic_session():
+    """Determine if we're in an agentic session based on the presence of COPILOT_AGENT_SESSION_ID."""
+    return os.environ.get(COPILOT_AGENT_SESSION_ID) is not None
+
+
 def build_agentic_session_params():
     """Read COPILOT_AGENT_SESSION_ID and build the agentic claims challenge.
 

src/azure-cli-core/azure/cli/core/auth/identity.py

@@ -145,7 +145,7 @@ def _service_principal_store(self):
             Identity._service_principal_store_instance = ServicePrincipalStore(store)
         return Identity._service_principal_store_instance
 
-    def login_with_auth_code(self, scopes, claims_challenge=None):
+    def login_with_auth_code(self, scopes, claims_challenge=None, use_broker_sso=False):
         # Emit a warning to inform that a browser is opened.
         # Only show the path part of the URL and hide the query string.
 
@@ -161,15 +161,30 @@ def _prompt_launching_ui(ui=None, **_):
         from .util import read_response_templates
         success_template, error_template = read_response_templates()
 
+        from .agentic_session import is_agentic_session
+        is_agentic_session_value = is_agentic_session()
+        # Broker is available only on Windows for now
+        broker_sso_available = sys.platform.startswith('win') and self._enable_broker_on_windows
+        logger.debug("use_broker_sso: %s, is_agentic_session: %s, broker_sso_available: %s",
+                     use_broker_sso, is_agentic_session_value, broker_sso_available)
+        use_broker_sso = (use_broker_sso or is_agentic_session_value) and broker_sso_available
+        prompt = 'none' if use_broker_sso else 'select_account'
+
         # For AAD, use port 0 to let the system choose arbitrary unused ephemeral port to avoid port collision
         # on port 8400 from the old design. However, ADFS only allows port 8400.
         result = self._msal_app.acquire_token_interactive(
-            scopes, prompt='select_account', port=8400 if self._is_adfs else None,
+            scopes,
+            prompt=prompt,
+            port=8400 if self._is_adfs else None,
             success_template=success_template, error_template=error_template,
             parent_window_handle=self._msal_app.CONSOLE_WINDOW_HANDLE, on_before_launching_ui=_prompt_launching_ui,
             enable_msa_passthrough=True,
             claims_challenge=claims_challenge)
-        return check_result(result)
+        parsed = check_result(result)
+        if use_broker_sso:
+            # log parsed result in debug level
+            logger.debug("Result from broker SSO login: %s", json.dumps(parsed, indent=4))
+        return parsed
 
     def login_with_device_code(self, scopes, claims_challenge=None):
         flow = self._msal_app.initiate_device_flow(scopes, claims_challenge=claims_challenge)

src/azure-cli/azure/cli/command_modules/profile/__init__.py

@@ -58,6 +58,8 @@ def load_arguments(self, command):
             c.argument('claims_challenge',
                        help="Base64-encoded claims challenge requested by a resource API in the "
                             "WWW-Authenticate header.")
+            c.argument('use_broker_sso', action='store_true',
+                       help="(Experimental) Enable broker SSO for login.")
             c.ignore('_subscription')  # hide the global subscription parameter
 
             # Skip subscription discovery

src/azure-cli/azure/cli/command_modules/profile/custom.py

@@ -134,7 +134,7 @@ def _select_and_set_active(profile, subscriptions):
 
 # pylint: disable=too-many-branches, too-many-locals
 def login(cmd, username=None, password=None, tenant=None, scopes=None, allow_no_subscriptions=False,
-          claims_challenge=None,
+          claims_challenge=None, use_broker_sso=False,
           # Device code flow
           use_device_code=False,
           # Service principal
@@ -169,6 +169,15 @@ def login(cmd, username=None, password=None, tenant=None, scopes=None, allow_no_
             logger.warning(USERNAME_PASSWORD_DEPRECATION_WARNING_AZURE_CLOUD)
         else:
             logger.warning(USERNAME_PASSWORD_DEPRECATION_WARNING_OTHER_CLOUD)
+    # broker_sso incompatible with workload identities
+    # broker_sso relies on the presence of a broker, which is only available on Windows (for now)
+    enable_broker_on_windows = cmd.cli_ctx.config.getboolean('core', 'enable_broker_on_windows', fallback=True)
+    broker_sso_available = sys.platform.startswith('win') and enable_broker_on_windows
+    if use_broker_sso and not broker_sso_available:
+        raise CLIError("usage error: '--use-broker-sso' is only supported on Windows with broker enabled")
+    if use_broker_sso and (service_principal or identity):
+        raise CLIError("usage error: '--use-broker-sso' is not applicable "
+                       "to service principal or managed identity login")
 
     if claims_challenge:
         from azure.cli.core.util import b64decode
@@ -219,6 +228,7 @@ def login(cmd, username=None, password=None, tenant=None, scopes=None, allow_no_
         service_principal,
         tenant,
         scopes=scopes,
+        use_broker_sso=use_broker_sso,
         use_device_code=use_device_code,
         allow_no_subscriptions=allow_no_subscriptions,
         use_cert_sn_issuer=use_cert_sn_issuer,