diff --git a/pyteal/ast/router.py b/pyteal/ast/router.py
index 27ec1d51b..994af7e07 100644
--- a/pyteal/ast/router.py
+++ b/pyteal/ast/router.py
@@ -29,7 +29,7 @@
 from pyteal.ast.methodsig import MethodSignature
 from pyteal.ast.naryexpr import And, Or
 from pyteal.ast.txn import Txn
-from pyteal.ast.return_ import Approve
+from pyteal.ast.return_ import Approve, Reject
 
 
 class CallConfig(IntFlag):
@@ -50,7 +50,7 @@ class CallConfig(IntFlag):
     CREATE = 2
     ALL = 3
 
-    def condition_under_config(self) -> Expr | int:
+    def approval_condition_under_config(self) -> Expr | int:
         match self:
             case CallConfig.NEVER:
                 return 0
@@ -63,6 +63,19 @@ def condition_under_config(self) -> Expr | int:
             case _:
                 raise TealInternalError(f"unexpected CallConfig {self}")
 
+    def clear_state_condition_under_config(self) -> int:
+        match self:
+            case CallConfig.NEVER:
+                return 0
+            case CallConfig.CALL:
+                return 1
+            case CallConfig.CREATE | CallConfig.ALL:
+                raise TealInputError(
+                    "Only CallConfig.CALL or CallConfig.NEVER are valid for a clear state CallConfig, since clear state can never be invoked during creation"
+                )
+            case _:
+                raise TealInputError(f"unexpected CallConfig {self}")
+
 
 CallConfig.__module__ = "pyteal"
 
@@ -101,7 +114,7 @@ def approval_cond(self) -> Expr | int:
         else:
             cond_list = []
             for config, oc in config_oc_pairs:
-                config_cond = config.condition_under_config()
+                config_cond = config.approval_condition_under_config()
                 match config_cond:
                     case Expr():
                         cond_list.append(And(Txn.on_completion() == oc, config_cond))
@@ -116,7 +129,7 @@ def approval_cond(self) -> Expr | int:
             return Or(*cond_list)
 
     def clear_state_cond(self) -> Expr | int:
-        return self.clear_state.condition_under_config()
+        return self.clear_state.clear_state_condition_under_config()
 
 
 @dataclass(frozen=True)
@@ -214,7 +227,11 @@ def approval_construction(self) -> Optional[Expr]:
                     cond_body = wrapped_handler
                 case CallConfig.CALL | CallConfig.CREATE:
                     cond_body = Seq(
-                        Assert(cast(Expr, oca.call_config.condition_under_config())),
+                        Assert(
+                            cast(
+                                Expr, oca.call_config.approval_condition_under_config()
+                            )
+                        ),
                         wrapped_handler,
                     )
                 case _:
@@ -233,29 +250,16 @@ def clear_state_construction(self) -> Optional[Expr]:
         if self.clear_state.is_empty():
             return None
 
-        wrapped_handler = ASTBuilder.wrap_handler(
+        # call this to make sure we error if the CallConfig is CREATE or ALL
+        self.clear_state.call_config.clear_state_condition_under_config()
+
+        return ASTBuilder.wrap_handler(
             False,
             cast(
                 Expr | SubroutineFnWrapper | ABIReturnSubroutine,
                 self.clear_state.action,
             ),
         )
-        match self.clear_state.call_config:
-            case CallConfig.ALL:
-                return wrapped_handler
-            case CallConfig.CALL | CallConfig.CREATE:
-                return Seq(
-                    Assert(
-                        cast(
-                            Expr, self.clear_state.call_config.condition_under_config()
-                        )
-                    ),
-                    wrapped_handler,
-                )
-            case _:
-                raise TealInternalError(
-                    f"Unexpected CallConfig: {self.clear_state.call_config!r}"
-                )
 
 
 BareCallActions.__module__ = "pyteal"
@@ -475,7 +479,7 @@ def add_method_to_ast(
 
     def program_construction(self) -> Expr:
         if not self.conditions_n_branches:
-            raise TealInputError("ABIRouter: Cannot build program with an empty AST")
+            return Reject()
         return Cond(*[[n.condition, n.branch] for n in self.conditions_n_branches])
 
 
@@ -659,6 +663,9 @@ def build_program(self) -> tuple[Expr, Expr, sdk_abi.Contract]:
         Constructs ASTs for approval and clear-state programs from the registered methods in the router,
         also generates a JSON object of contract to allow client read and call the methods easily.
 
+        Note that if no methods or bare app call actions have been registered to either the approval
+        or clear state programs, then that program will reject all transactions.
+
         Returns:
             approval_program: AST for approval program
             clear_state_program: AST for clear-state program
@@ -681,6 +688,9 @@ def compile_program(
         Combining `build_program` and `compileTeal`, compiles built Approval and ClearState programs
         and returns Contract JSON object for off-chain calling.
 
+        Note that if no methods or bare app call actions have been registered to either the approval
+        or clear state programs, then that program will reject all transactions.
+
         Returns:
             approval_program: compiled approval program
             clear_state_program: compiled clear-state program
diff --git a/pyteal/ast/router_test.py b/pyteal/ast/router_test.py
index 4390f0109..157e9c41c 100644
--- a/pyteal/ast/router_test.py
+++ b/pyteal/ast/router_test.py
@@ -266,8 +266,8 @@ def camel_to_snake(name: str) -> str:
 
 def test_call_config():
     for cc in pt.CallConfig:
-        cond_on_cc: pt.Expr | int = cc.condition_under_config()
-        match cond_on_cc:
+        approval_cond_on_cc: pt.Expr | int = cc.approval_condition_under_config()
+        match approval_cond_on_cc:
             case pt.Expr():
                 expected_cc = (
                     (pt.Txn.application_id() == pt.Int(0))
@@ -275,11 +275,34 @@ def test_call_config():
                     else (pt.Txn.application_id() != pt.Int(0))
                 )
                 with pt.TealComponent.Context.ignoreExprEquality():
-                    assert assemble_helper(cond_on_cc) == assemble_helper(expected_cc)
+                    assert assemble_helper(approval_cond_on_cc) == assemble_helper(
+                        expected_cc
+                    )
             case int():
-                assert cond_on_cc == int(cc) & 1
+                assert approval_cond_on_cc == int(cc) & 1
+            case _:
+                raise pt.TealInternalError(
+                    f"unexpected approval_cond_on_cc {approval_cond_on_cc}"
+                )
+
+        if cc in (pt.CallConfig.CREATE, pt.CallConfig.ALL):
+            with pytest.raises(
+                pt.TealInputError,
+                match=r"Only CallConfig.CALL or CallConfig.NEVER are valid for a clear state CallConfig, since clear state can never be invoked during creation$",
+            ):
+                cc.clear_state_condition_under_config()
+            continue
+
+        clear_state_cond_on_cc: int = cc.clear_state_condition_under_config()
+        match clear_state_cond_on_cc:
+            case 0:
+                assert cc == pt.CallConfig.NEVER
+            case 1:
+                assert cc == pt.CallConfig.CALL
             case _:
-                raise pt.TealInternalError(f"unexpected cond_on_cc {cond_on_cc}")
+                raise pt.TealInternalError(
+                    f"unexpected clear_state_cond_on_cc {clear_state_cond_on_cc}"
+                )
 
 
 def test_method_config():
@@ -304,18 +327,14 @@ def test_method_config():
             match mc.clear_state:
                 case pt.CallConfig.NEVER:
                     assert mc.clear_state_cond() == 0
-                case pt.CallConfig.ALL:
-                    assert mc.clear_state_cond() == 1
                 case pt.CallConfig.CALL:
-                    with pt.TealComponent.Context.ignoreExprEquality():
-                        assert assemble_helper(
-                            mc.clear_state_cond()
-                        ) == assemble_helper(pt.Txn.application_id() != pt.Int(0))
-                case pt.CallConfig.CREATE:
-                    with pt.TealComponent.Context.ignoreExprEquality():
-                        assert assemble_helper(
-                            mc.clear_state_cond()
-                        ) == assemble_helper(pt.Txn.application_id() == pt.Int(0))
+                    assert mc.clear_state_cond() == 1
+                case pt.CallConfig.CREATE | pt.CallConfig.ALL:
+                    with pytest.raises(
+                        pt.TealInputError,
+                        match=r"Only CallConfig.CALL or CallConfig.NEVER are valid for a clear state CallConfig, since clear state can never be invoked during creation$",
+                    ):
+                        mc.clear_state_cond()
             if mc.is_never() or all(
                 getattr(mc, i) == pt.CallConfig.NEVER
                 for i, _ in approval_check_names_n_ocs
@@ -330,7 +349,9 @@ def test_method_config():
                 continue
             list_of_cc = [
                 (
-                    typing.cast(pt.CallConfig, getattr(mc, i)).condition_under_config(),
+                    typing.cast(
+                        pt.CallConfig, getattr(mc, i)
+                    ).approval_condition_under_config(),
                     oc,
                 )
                 for i, oc in approval_check_names_n_ocs
@@ -624,3 +645,146 @@ def test_contract_json_obj():
     sdk_contract = sdk_abi.Contract(contract_name, method_list)
     contract = router.contract_construct()
     assert contract == sdk_contract
+
+
+def test_build_program_all_empty():
+    router = pt.Router("test")
+
+    approval, clear_state, contract = router.build_program()
+
+    expected_empty_program = pt.TealSimpleBlock(
+        [
+            pt.TealOp(None, pt.Op.int, 0),
+            pt.TealOp(None, pt.Op.return_),
+        ]
+    )
+
+    with pt.TealComponent.Context.ignoreExprEquality():
+        assert assemble_helper(approval) == expected_empty_program
+        assert assemble_helper(clear_state) == expected_empty_program
+
+    expected_contract = sdk_abi.Contract("test", [])
+    assert contract == expected_contract
+
+
+def test_build_program_approval_empty():
+    router = pt.Router(
+        "test",
+        pt.BareCallActions(clear_state=pt.OnCompleteAction.call_only(pt.Approve())),
+    )
+
+    approval, clear_state, contract = router.build_program()
+
+    expected_empty_program = pt.TealSimpleBlock(
+        [
+            pt.TealOp(None, pt.Op.int, 0),
+            pt.TealOp(None, pt.Op.return_),
+        ]
+    )
+
+    with pt.TealComponent.Context.ignoreExprEquality():
+        assert assemble_helper(approval) == expected_empty_program
+        assert assemble_helper(clear_state) != expected_empty_program
+
+    expected_contract = sdk_abi.Contract("test", [])
+    assert contract == expected_contract
+
+
+def test_build_program_clear_state_empty():
+    router = pt.Router(
+        "test", pt.BareCallActions(no_op=pt.OnCompleteAction.always(pt.Approve()))
+    )
+
+    approval, clear_state, contract = router.build_program()
+
+    expected_empty_program = pt.TealSimpleBlock(
+        [
+            pt.TealOp(None, pt.Op.int, 0),
+            pt.TealOp(None, pt.Op.return_),
+        ]
+    )
+
+    with pt.TealComponent.Context.ignoreExprEquality():
+        assert assemble_helper(approval) != expected_empty_program
+        assert assemble_helper(clear_state) == expected_empty_program
+
+    expected_contract = sdk_abi.Contract("test", [])
+    assert contract == expected_contract
+
+
+def test_build_program_clear_state_invalid_config():
+    for config in (pt.CallConfig.CREATE, pt.CallConfig.ALL):
+        bareCalls = pt.BareCallActions(
+            clear_state=pt.OnCompleteAction(action=pt.Approve(), call_config=config)
+        )
+        with pytest.raises(
+            pt.TealInputError,
+            match=r"Only CallConfig.CALL or CallConfig.NEVER are valid for a clear state CallConfig, since clear state can never be invoked during creation$",
+        ):
+            pt.Router("test", bareCalls)
+
+        router = pt.Router("test")
+
+        @pt.ABIReturnSubroutine
+        def clear_state_method():
+            return pt.Approve()
+
+        with pytest.raises(
+            pt.TealInputError,
+            match=r"Only CallConfig.CALL or CallConfig.NEVER are valid for a clear state CallConfig, since clear state can never be invoked during creation$",
+        ):
+            router.add_method_handler(
+                clear_state_method,
+                method_config=pt.MethodConfig(clear_state=config),
+            )
+
+
+def test_build_program_clear_state_valid_config():
+    action = pt.If(pt.Txn.fee() == pt.Int(4)).Then(pt.Approve()).Else(pt.Reject())
+    config = pt.CallConfig.CALL
+
+    router_with_bare_call = pt.Router(
+        "test",
+        pt.BareCallActions(
+            clear_state=pt.OnCompleteAction(action=action, call_config=config)
+        ),
+    )
+    _, actual_clear_state_with_bare_call, _ = router_with_bare_call.build_program()
+
+    expected_clear_state_with_bare_call = assemble_helper(
+        pt.Cond([pt.Txn.application_args.length() == pt.Int(0), action])
+    )
+
+    with pt.TealComponent.Context.ignoreExprEquality():
+        assert (
+            assemble_helper(actual_clear_state_with_bare_call)
+            == expected_clear_state_with_bare_call
+        )
+
+    router_with_method = pt.Router("test")
+
+    @pt.ABIReturnSubroutine
+    def clear_state_method():
+        return action
+
+    router_with_method.add_method_handler(
+        clear_state_method, method_config=pt.MethodConfig(clear_state=config)
+    )
+
+    _, actual_clear_state_with_method, _ = router_with_method.build_program()
+
+    expected_clear_state_with_method = assemble_helper(
+        pt.Cond(
+            [
+                pt.Txn.application_args[0]
+                == pt.MethodSignature("clear_state_method()void"),
+                pt.Seq(clear_state_method(), pt.Approve()),
+            ]
+        )
+    )
+
+    with pt.TealComponent.Context.ignoreExprEquality():
+        assert (
+            assemble_helper(actual_clear_state_with_method)
+            == expected_clear_state_with_method
+        )
diff --git a/pyteal/compiler/compiler_test.py b/pyteal/compiler/compiler_test.py
index 1aa88a6cc..fb1172a2d 100644
--- a/pyteal/compiler/compiler_test.py
+++ b/pyteal/compiler/compiler_test.py
@@ -2830,10 +2830,6 @@ def approve_if_odd(condition_encoding: pt.abi.Uint32) -> pt.Expr:
 bnz main_l5
 err
 main_l5:
-txn ApplicationID
-int 0
-!=
-assert
 txna ApplicationArgs 1
 int 0
 extract_uint32
@@ -2843,10 +2839,6 @@ def approve_if_odd(condition_encoding: pt.abi.Uint32) -> pt.Expr:
 int 1
 return
 main_l6:
-txn ApplicationID
-int 0
-!=
-assert
 callsub log1_1
 store 1
 byte 0x151f7c75
@@ -2857,18 +2849,10 @@ def approve_if_odd(condition_encoding: pt.abi.Uint32) -> pt.Expr:
 int 1
 return
 main_l7:
-txn ApplicationID
-int 0
-!=
-assert
 callsub emptyreturnsubroutine_0
 int 1
 return
 main_l8:
-txn ApplicationID
-int 0
-!=
-assert
 int 1
 return
 
@@ -3369,10 +3353,6 @@ def approve_if_odd(condition_encoding: pt.abi.Uint32) -> pt.Expr:
 bnz main_l4
 err
 main_l4:
-txn ApplicationID
-int 0
-!=
-assert
 txna ApplicationArgs 1
 int 0
 extract_uint32
@@ -3382,10 +3362,6 @@ def approve_if_odd(condition_encoding: pt.abi.Uint32) -> pt.Expr:
 int 1
 return
 main_l5:
-txn ApplicationID
-int 0
-!=
-assert
 callsub log1_1
 store 1
 byte 0x151f7c75
@@ -3396,10 +3372,6 @@ def approve_if_odd(condition_encoding: pt.abi.Uint32) -> pt.Expr:
 int 1
 return
 main_l6:
-txn ApplicationID
-int 0
-!=
-assert
 callsub emptyreturnsubroutine_0
 int 1
 return