diff --git a/core/src/ten_runtime/extension/internal/metadata.c b/core/src/ten_runtime/extension/internal/metadata.c
index 6028d9166..03a700c2f 100644
--- a/core/src/ten_runtime/extension/internal/metadata.c
+++ b/core/src/ten_runtime/extension/internal/metadata.c
@@ -197,10 +197,12 @@ static bool ten_extension_graph_property_resolve_placeholders(
         ten_placeholder_init(&placeholder);
 
         if (!ten_placeholder_parse(&placeholder, str_value, err)) {
+          ten_placeholder_deinit(&placeholder);
           return false;
         }
 
         if (!ten_placeholder_resolve(&placeholder, curr_value, err)) {
+          ten_placeholder_deinit(&placeholder);
           return false;
         }
 
diff --git a/core/src/ten_runtime/extension/ten_env/on_xxx.c b/core/src/ten_runtime/extension/ten_env/on_xxx.c
index 853743944..22e163350 100644
--- a/core/src/ten_runtime/extension/ten_env/on_xxx.c
+++ b/core/src/ten_runtime/extension/ten_env/on_xxx.c
@@ -137,7 +137,12 @@ bool ten_extension_on_configure_done(ten_env_t *self) {
   }
 
   rc = ten_extension_resolve_properties_in_graph(extension, &err);
-  TEN_ASSERT(rc, "Failed to resolve properties in graph.");
+  if (!rc) {
+    TEN_LOGW(
+        "Failed to resolve properties in graph: %s, use the raw property data "
+        "instead.",
+        ten_error_message(&err));
+  }
 
   ten_extension_merge_properties_from_graph(extension);
 
diff --git a/core/src/ten_utils/lib/sys/general/placeholder.c b/core/src/ten_utils/lib/sys/general/placeholder.c
index e1022fa1a..398570930 100644
--- a/core/src/ten_utils/lib/sys/general/placeholder.c
+++ b/core/src/ten_utils/lib/sys/general/placeholder.c
@@ -86,7 +86,6 @@ static TEN_PLACEHOLDER_SCOPE ten_placeholder_scope_from_string(
   if (!strcmp(scope_str, TEN_STR_ENV)) {
     return TEN_PLACEHOLDER_SCOPE_ENV;
   } else {
-    TEN_ASSERT(0, "Should not happen.");
     return TEN_PLACEHOLDER_SCOPE_INVALID;
   }
 }
@@ -130,6 +129,11 @@ bool ten_placeholder_parse(ten_placeholder_t *self, const char *input,
   char *scope_end = strchr(content, TEN_STR_PLACEHOLDER_SCOPE_DELIMITER);
   if (!scope_end) {
     TEN_FREE(content);
+    if (err) {
+      ten_error_set(err, TEN_ERROR_CODE_GENERIC,
+                    "Invalid placeholder format: %s, missing scope delimiter.",
+                    input);
+    }
     return false;
   }
 
@@ -215,7 +219,6 @@ bool ten_placeholder_resolve(ten_placeholder_t *self,
         ten_error_set(err, TEN_ERROR_CODE_GENERIC,
                       "Unsupported placeholder scope: %d", self->scope);
       }
-      TEN_ASSERT(0, "Should not happen.");
       return false;
   }
 
diff --git a/tests/ten_runtime/integration/cpp/BUILD.gn b/tests/ten_runtime/integration/cpp/BUILD.gn
index 70ef73048..eb393bd50 100644
--- a/tests/ten_runtime/integration/cpp/BUILD.gn
+++ b/tests/ten_runtime/integration/cpp/BUILD.gn
@@ -12,6 +12,7 @@ group("cpp") {
     "graph_env_var_1",
     "graph_env_var_2",
     "graph_env_var_3",
+    "graph_env_var_4",
     "hello_world",
     "large_result",
     "restful",
diff --git a/tests/ten_runtime/integration/cpp/graph_env_var_4/BUILD.gn b/tests/ten_runtime/integration/cpp/graph_env_var_4/BUILD.gn
new file mode 100644
index 000000000..9b7143079
--- /dev/null
+++ b/tests/ten_runtime/integration/cpp/graph_env_var_4/BUILD.gn
@@ -0,0 +1,85 @@
+#
+# Copyright © 2025 Agora
+# This file is part of TEN Framework, an open source project.
+# Licensed under the Apache License, Version 2.0, with certain conditions.
+# Refer to the "LICENSE" file in the root directory for more information.
+#
+import("//build/ten_runtime/feature/test.gni")
+import("//build/ten_runtime/ten.gni")
+
+ten_package_test_prepare_app("graph_env_var_4_app") {
+  src_app = "default_app_cpp"
+  src_app_language = "cpp"
+  generated_app_src_root_dir_name = "graph_env_var_4_app"
+
+  replace_paths_after_install_app = [
+    "graph_env_var_4_app/manifest.json",
+    "graph_env_var_4_app/property.json",
+  ]
+
+  replace_paths_after_install_all = [
+    "graph_env_var_4_app/ten_packages/extension/default_extension_cpp/manifest.json",
+    "graph_env_var_4_app/ten_packages/extension/default_extension_cpp/property.json",
+    "graph_env_var_4_app/ten_packages/extension/default_extension_cpp/src/main.cc",
+    "graph_env_var_4_app/ten_packages/extension/default_extension_cpp/BUILD.gn",
+  ]
+
+  if (ten_enable_ten_manager) {
+    deps = [
+      "//core/src/ten_manager",
+      "//core/src/ten_runtime:upload_ten_runtime_system_package_to_server",
+      "//packages/core_apps/default_app_cpp:upload_default_app_cpp_to_server",
+      "//packages/core_extensions/default_extension_cpp:upload_default_extension_cpp_to_server",
+      "//packages/core_protocols/msgpack:upload_protocol_msgpack_to_server",
+    ]
+  }
+}
+
+ten_package_test_prepare_client("graph_env_var_4_app_client") {
+  sources = [ "client/client.cc" ]
+  include_dirs = [
+    "//core/src",
+    "//core",
+    "//packages",
+    "//tests",
+  ]
+  deps = [
+    "//core/src/ten_runtime",
+    "//packages/core_protocols/msgpack:msgpack_files",
+    "//tests/common/client:msgpack_client",
+    "//third_party/msgpack:msgpackc",
+    "//third_party/nlohmann_json",
+  ]
+}
+
+ten_package_test_prepare_auxiliary_resources("graph_env_var_4_app_test_files") {
+  resources = [
+    "__init__.py",
+    "test_case.py",
+  ]
+
+  common_files =
+      exec_script("//.gnfiles/build/scripts/glob_file.py",
+                  [
+                    "--dir",
+                    rebase_path("//tests/ten_runtime/integration/common/**/*"),
+                    "--dir-base",
+                    rebase_path("//tests/ten_runtime/integration/common"),
+                    "--recursive",
+                    "--only-output-file",
+                  ],
+                  "json")
+
+  foreach(common_file, common_files) {
+    common_file_rel_path = common_file.relative_path
+    resources += [ "//tests/ten_runtime/integration/common/${common_file_rel_path}=>common/${common_file_rel_path}" ]
+  }
+}
+
+group("graph_env_var_4") {
+  deps = [
+    ":graph_env_var_4_app",
+    ":graph_env_var_4_app_client",
+    ":graph_env_var_4_app_test_files",
+  ]
+}
diff --git a/tests/ten_runtime/integration/cpp/graph_env_var_4/__init__.py b/tests/ten_runtime/integration/cpp/graph_env_var_4/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/tests/ten_runtime/integration/cpp/graph_env_var_4/client/client.cc b/tests/ten_runtime/integration/cpp/graph_env_var_4/client/client.cc
new file mode 100644
index 000000000..87d07ac2d
--- /dev/null
+++ b/tests/ten_runtime/integration/cpp/graph_env_var_4/client/client.cc
@@ -0,0 +1,46 @@
+//
+// Copyright © 2025 Agora
+// This file is part of TEN Framework, an open source project.
+// Licensed under the Apache License, Version 2.0, with certain conditions.
+// Refer to the "LICENSE" file in the root directory for more information.
+//
+#include <nlohmann/json.hpp>
+
+#include "tests/common/client/cpp/msgpack_tcp.h"
+
+int main(int argc, char **argv) {
+  // Create a client and connect to the app.
+  auto *client = new ten::msgpack_tcp_client_t("msgpack://127.0.0.1:8001/");
+
+  // Send graph.
+  auto start_graph_cmd = ten::cmd_start_graph_t::create();
+  start_graph_cmd->set_graph_from_json(R"({
+           "nodes": [{
+               "type": "extension",
+               "name": "test_extension",
+               "addon": "default_extension_cpp",
+               "app": "msgpack://127.0.0.1:8001/",
+               "extension_group": "test_extension_group",
+               "property": {
+                 "prop": "${abc}"
+               }
+             }]
+           })");
+  auto cmd_result =
+      client->send_cmd_and_recv_result(std::move(start_graph_cmd));
+  TEN_ASSERT(TEN_STATUS_CODE_OK == cmd_result->get_status_code(),
+             "Should not happen.");
+
+  // Send a user-defined 'hello world' command.
+  auto hello_world_cmd = ten::cmd_t::create("hello_world");
+  hello_world_cmd->set_dest("msgpack://127.0.0.1:8001/", nullptr,
+                            "test_extension_group", "test_extension");
+  cmd_result = client->send_cmd_and_recv_result(std::move(hello_world_cmd));
+  TEN_ASSERT(TEN_STATUS_CODE_OK == cmd_result->get_status_code(),
+             "Should not happen.");
+  TEN_ASSERT(static_cast<std::string>("hello world, too") ==
+                 cmd_result->get_property_string("detail"),
+             "Should not happen.");
+
+  delete client;
+}
diff --git a/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/manifest.json b/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/manifest.json
new file mode 100644
index 000000000..6f407e87a
--- /dev/null
+++ b/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/manifest.json
@@ -0,0 +1,22 @@
+{
+  "type": "app",
+  "name": "default_app_cpp",
+  "version": "0.8.18",
+  "dependencies": [
+    {
+      "type": "system",
+      "name": "ten_runtime",
+      "version": "0.8.18"
+    },
+    {
+      "type": "extension",
+      "name": "default_extension_cpp",
+      "version": "0.8.18"
+    },
+    {
+      "type": "protocol",
+      "name": "msgpack",
+      "version": "0.8.18"
+    }
+  ]
+}
\ No newline at end of file
diff --git a/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/property.json b/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/property.json
new file mode 100644
index 000000000..43cdb3460
--- /dev/null
+++ b/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/property.json
@@ -0,0 +1,5 @@
+{
+  "_ten": {
+    "uri": "msgpack://127.0.0.1:8001/"
+  }
+}
\ No newline at end of file
diff --git a/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/ten_packages/extension/default_extension_cpp/BUILD.gn b/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/ten_packages/extension/default_extension_cpp/BUILD.gn
new file mode 100644
index 000000000..9e148e2c6
--- /dev/null
+++ b/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/ten_packages/extension/default_extension_cpp/BUILD.gn
@@ -0,0 +1,20 @@
+#
+# Copyright © 2025 Agora
+# This file is part of TEN Framework, an open source project.
+# Licensed under the Apache License, Version 2.0, with certain conditions.
+# Refer to the "LICENSE" file in the root directory for more information.
+#
+import("//build/feature/ten_package.gni")
+
+ten_package("default_extension_cpp") {
+  package_kind = "extension"
+  enable_build = true
+
+  resources = [
+    "manifest.json",
+    "property.json",
+  ]
+
+  sources = [ "src/main.cc" ]
+  include_dirs = [ "//core/include" ]
+}
diff --git a/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/ten_packages/extension/default_extension_cpp/manifest.json b/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/ten_packages/extension/default_extension_cpp/manifest.json
new file mode 100644
index 000000000..e3163045b
--- /dev/null
+++ b/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/ten_packages/extension/default_extension_cpp/manifest.json
@@ -0,0 +1,32 @@
+{
+  "type": "extension",
+  "name": "default_extension_cpp",
+  "version": "0.8.18",
+  "dependencies": [
+    {
+      "type": "system",
+      "name": "ten_runtime",
+      "version": "0.8.18"
+    }
+  ],
+  "package": {
+    "include": [
+      "**"
+    ]
+  },
+  "api": {
+    "cmd_in": [
+      {
+        "name": "hello_world"
+      }
+    ],
+    "cmd_out": [],
+    "data_in": [],
+    "data_out": [],
+    "video_frame_in": [],
+    "video_frame_out": [],
+    "audio_frame_in": [],
+    "audio_frame_out": [],
+    "interface_in": []
+  }
+}
\ No newline at end of file
diff --git a/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/ten_packages/extension/default_extension_cpp/property.json b/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/ten_packages/extension/default_extension_cpp/property.json
new file mode 100644
index 000000000..17a9ab8da
--- /dev/null
+++ b/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/ten_packages/extension/default_extension_cpp/property.json
@@ -0,0 +1,3 @@
+{
+  "prop": "default_value"
+}
\ No newline at end of file
diff --git a/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/ten_packages/extension/default_extension_cpp/src/main.cc b/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/ten_packages/extension/default_extension_cpp/src/main.cc
new file mode 100644
index 000000000..d63c1f244
--- /dev/null
+++ b/tests/ten_runtime/integration/cpp/graph_env_var_4/graph_env_var_4_app/ten_packages/extension/default_extension_cpp/src/main.cc
@@ -0,0 +1,39 @@
+//
+// Copyright © 2025 Agora
+// This file is part of TEN Framework, an open source project.
+// Licensed under the Apache License, Version 2.0, with certain conditions.
+// Refer to the "LICENSE" file in the root directory for more information.
+//
+#include <cassert>
+#include <cstdlib>
+
+#include "ten_runtime/binding/cpp/ten.h"
+
+class test_extension : public ten::extension_t {
+ public:
+  explicit test_extension(const char *name) : ten::extension_t(name) {}
+
+  void on_init(ten::ten_env_t &ten_env) override { ten_env.on_init_done(); }
+
+  void on_start(ten::ten_env_t &ten_env) override {
+    // The property.json will be loaded by default during `on_init` phase, so
+    // the property `prop` should be available here.
+    auto prop = ten_env.get_property_string("prop");
+    if (prop != "${abc}") {
+      assert(0 && "Should not happen.");
+    }
+
+    ten_env.on_start_done();
+  }
+
+  void on_cmd(ten::ten_env_t &ten_env,
+              std::unique_ptr<ten::cmd_t> cmd) override {
+    if (cmd->get_name() == "hello_world") {
+      auto cmd_result = ten::cmd_result_t::create(TEN_STATUS_CODE_OK);
+      cmd_result->set_property("detail", "hello world, too");
+      ten_env.return_result(std::move(cmd_result), std::move(cmd));
+    }
+  }
+};
+
+TEN_CPP_REGISTER_ADDON_AS_EXTENSION(default_extension_cpp, test_extension);
diff --git a/tests/ten_runtime/integration/cpp/graph_env_var_4/test_case.py b/tests/ten_runtime/integration/cpp/graph_env_var_4/test_case.py
new file mode 100644
index 000000000..9f1172026
--- /dev/null
+++ b/tests/ten_runtime/integration/cpp/graph_env_var_4/test_case.py
@@ -0,0 +1,164 @@
+"""
+Test graph_env_var_4_app.
+"""
+
+import subprocess
+import os
+import sys
+from sys import stdout
+from .common import msgpack, build_config, build_pkg
+
+
+def test_graph_env_var_4_app():
+    """Test client and app server."""
+    base_path = os.path.dirname(os.path.abspath(__file__))
+    root_dir = os.path.join(base_path, "../../../../../")
+
+    my_env = os.environ.copy()
+
+    app_dir_name = "graph_env_var_4_app"
+    app_root_path = os.path.join(base_path, app_dir_name)
+    app_language = "cpp"
+
+    build_config_args = build_config.parse_build_config(
+        os.path.join(root_dir, "tgn_args.txt"),
+    )
+
+    if build_config_args.ten_enable_integration_tests_prebuilt is False:
+        # Before starting, cleanup the old app package.
+        build_pkg.cleanup(app_root_path)
+
+        print('Assembling and building package "{}".'.format(app_dir_name))
+
+        rc = build_pkg.prepare_and_build_app(
+            build_config_args,
+            root_dir,
+            base_path,
+            app_dir_name,
+            app_language,
+        )
+        if rc != 0:
+            assert False, "Failed to build package."
+
+    tman_install_cmd = [
+        os.path.join(root_dir, "ten_manager/bin/tman"),
+        "--config-file",
+        os.path.join(root_dir, "tests/local_registry/config.json"),
+        "--yes",
+        "install",
+    ]
+
+    tman_install_process = subprocess.Popen(
+        tman_install_cmd,
+        stdout=stdout,
+        stderr=subprocess.STDOUT,
+        env=my_env,
+        cwd=app_root_path,
+    )
+    tman_install_process.wait()
+    return_code = tman_install_process.returncode
+    if return_code != 0:
+        assert False, "Failed to install package."
+
+    if sys.platform == "win32":
+        my_env["PATH"] = (
+            os.path.join(
+                base_path,
+                "graph_env_var_4_app/ten_packages/system/ten_runtime/lib",
+            )
+            + ";"
+            + my_env["PATH"]
+        )
+        server_cmd = os.path.join(
+            base_path,
+            "graph_env_var_4_app/bin/graph_env_var_4_app.exe",
+        )
+        client_cmd = os.path.join(base_path, "graph_env_var_4_app_client.exe")
+    elif sys.platform == "darwin":
+        # client depends on some libraries in the TEN app.
+        my_env["DYLD_LIBRARY_PATH"] = os.path.join(
+            base_path,
+            "graph_env_var_4_app/ten_packages/system/ten_runtime/lib",
+        )
+        server_cmd = os.path.join(
+            base_path,
+            "graph_env_var_4_app/bin/graph_env_var_4_app",
+        )
+        client_cmd = os.path.join(base_path, "graph_env_var_4_app_client")
+    else:
+        # client depends on some libraries in the TEN app.
+        my_env["LD_LIBRARY_PATH"] = os.path.join(
+            base_path,
+            "graph_env_var_4_app/ten_packages/system/ten_runtime/lib",
+        )
+        server_cmd = os.path.join(
+            base_path,
+            "graph_env_var_4_app/bin/graph_env_var_4_app",
+        )
+        client_cmd = os.path.join(base_path, "graph_env_var_4_app_client")
+
+        if (
+            build_config_args.enable_sanitizer
+            and not build_config_args.is_clang
+        ):
+            libasan_path = os.path.join(
+                base_path,
+                "graph_env_var_4_app/ten_packages/system/ten_runtime/lib/libasan.so",
+            )
+            if os.path.exists(libasan_path):
+                print("Using AddressSanitizer library.")
+                my_env["LD_PRELOAD"] = libasan_path
+
+    my_env["TEST_ENV_VAR"] = "set_from_real_env_var"
+
+    if not os.path.isfile(server_cmd):
+        print(f"Server command '{server_cmd}' does not exist.")
+        assert False
+
+    server = subprocess.Popen(
+        server_cmd,
+        stdout=stdout,
+        stderr=subprocess.STDOUT,
+        env=my_env,
+        cwd=app_root_path,
+    )
+
+    is_started, sock = msgpack.is_app_started("127.0.0.1", 8001, 10)
+    if not is_started:
+        print("The graph_env_var_4_app is not started after 10 seconds.")
+
+        server.kill()
+        exit_code = server.wait()
+        print(
+            "The exit code of graph_env_var_4_app: ",
+            exit_code,
+        )
+
+        assert exit_code == 0
+        assert False
+
+        return
+
+    client = subprocess.Popen(
+        client_cmd, stdout=stdout, stderr=subprocess.STDOUT, env=my_env
+    )
+
+    # The client will quit after the test is completed.
+    client_rc = client.wait()
+    if client_rc != 0:
+        server.kill()
+
+    # We cannot shutdown the socket before the client is closed, due to it will
+    # trigger the GC of the app server.
+    sock.close()
+
+    server_rc = server.wait()
+    print("server: ", server_rc)
+    print("client: ", client_rc)
+    assert server_rc == 0
+    assert client_rc == 0
+
+    if build_config_args.ten_enable_integration_tests_prebuilt is False:
+        # Testing complete. If builds are only created during the testing phase,
+        # we can clear the build results to save disk space.
+        build_pkg.cleanup(app_root_path)