diff --git a/ci/scripts/notify.py b/ci/scripts/notify.py
index 5266998b0045..9160d0167583 100755
--- a/ci/scripts/notify.py
+++ b/ci/scripts/notify.py
@@ -98,6 +98,7 @@ def get_mock_test_status(test):
         "e2e-clickhouse-sink-tests": "hard_failed",
         "e2e-pulsar-sink-tests": "",
         "s3-source-test-for-opendal-fs-engine": "",
+        "s3-source-tests": "",
         "pulsar-source-tests": "",
         "connector-node-integration-test": ""
     }
diff --git a/ci/scripts/s3-source-test-for-opendal-fs-engine.sh b/ci/scripts/s3-source-test-for-opendal-fs-engine.sh
index 6fbbdb35e0e4..355489acf251 100755
--- a/ci/scripts/s3-source-test-for-opendal-fs-engine.sh
+++ b/ci/scripts/s3-source-test-for-opendal-fs-engine.sh
@@ -30,7 +30,7 @@ cargo make ci-start ci-3cn-3fe-opendal-fs-backend
 
 echo "--- Run test"
 python3 -m pip install minio psycopg2-binary
-python3 e2e_test/s3/$script.py
+python3 e2e_test/s3/$script
 
 echo "--- Kill cluster"
 rm -rf /tmp/rw_ci
diff --git a/ci/workflows/main-cron.yml b/ci/workflows/main-cron.yml
index 653578e4688e..d931c3af1666 100644
--- a/ci/workflows/main-cron.yml
+++ b/ci/workflows/main-cron.yml
@@ -490,6 +490,7 @@ steps:
     retry: *auto-retry
 
   - label: "PosixFs source on OpenDAL fs engine (csv parser)"
+    key: "s3-source-test-for-opendal-fs-engine"
     command: "ci/scripts/s3-source-test.sh -p ci-release -s 'posix_fs_source.py csv_without_header'"
     if: |
       !(build.pull_request.labels includes "ci/main-cron/skip-ci") && build.env("CI_STEPS") == null
@@ -507,7 +508,7 @@ steps:
 
   - label: "S3 source on OpenDAL fs engine"
     key: "s3-source-test-for-opendal-fs-engine"
-    command: "ci/scripts/s3-source-test-for-opendal-fs-engine.sh -p ci-release -s run"
+    command: "ci/scripts/s3-source-test-for-opendal-fs-engine.sh -p ci-release -s run.csv"
     if: |
       !(build.pull_request.labels includes "ci/main-cron/skip-ci") && build.env("CI_STEPS") == null
       || build.pull_request.labels includes "ci/run-s3-source-tests"
@@ -527,6 +528,29 @@ steps:
     timeout_in_minutes: 20
     retry: *auto-retry
 
+  # TODO(Kexiang): Enable this test after we have a GCS_SOURCE_TEST_CONF.
+  # - label: "GCS source on OpenDAL fs engine"
+  #   key: "s3-source-test-for-opendal-fs-engine"
+  #   command: "ci/scripts/s3-source-test-for-opendal-fs-engine.sh -p ci-release -s gcs.csv"
+  #   if: |
+  #     !(build.pull_request.labels includes "ci/main-cron/skip-ci") && build.env("CI_STEPS") == null
+  #     || build.pull_request.labels includes "ci/run-s3-source-tests"
+  #     || build.env("CI_STEPS") =~ /(^|,)s3-source-tests?(,|$$)/
+  #   depends_on: build
+  #   plugins:
+  #     - seek-oss/aws-sm#v2.3.1:
+  #         env:
+  #           S3_SOURCE_TEST_CONF: ci_s3_source_test_aws
+  #     - docker-compose#v4.9.0:
+  #         run: rw-build-env
+  #         config: ci/docker-compose.yml
+  #         mount-buildkite-agent: true
+  #         environment:
+  #           - S3_SOURCE_TEST_CONF
+  #     - ./ci/plugins/upload-failure-logs
+  #   timeout_in_minutes: 20
+  #   retry: *auto-retry
+
   - label: "pulsar source check"
     key: "pulsar-source-tests"
     command: "ci/scripts/pulsar-source-test.sh -p ci-release"
diff --git a/src/connector/src/source/filesystem/opendal_source/gcs_source.rs b/src/connector/src/source/filesystem/opendal_source/gcs_source.rs
index 7d9c2bec4429..d6f7b44bff59 100644
--- a/src/connector/src/source/filesystem/opendal_source/gcs_source.rs
+++ b/src/connector/src/source/filesystem/opendal_source/gcs_source.rs
@@ -32,9 +32,13 @@ impl<Src: OpendalSource> OpendalEnumerator<Src> {
         builder.bucket(&gcs_properties.bucket_name);
 
         // if credential env is set, use it. Otherwise, ADC will be used.
-        let cred = gcs_properties.credential;
-        if let Some(cred) = cred {
+        if let Some(cred) = gcs_properties.credential {
             builder.credential(&cred);
+        } else {
+            let cred = std::env::var("GOOGLE_APPLICATION_CREDENTIALS");
+            if let Ok(cred) = cred {
+                builder.credential(&cred);
+            }
         }
 
         if let Some(service_account) = gcs_properties.service_account {
diff --git a/src/connector/src/source/filesystem/opendal_source/mod.rs b/src/connector/src/source/filesystem/opendal_source/mod.rs
index d6223c467d08..e0c5a22f1fd9 100644
--- a/src/connector/src/source/filesystem/opendal_source/mod.rs
+++ b/src/connector/src/source/filesystem/opendal_source/mod.rs
@@ -38,10 +38,15 @@ pub const POSIX_FS_CONNECTOR: &str = "posix_fs";
 pub struct GcsProperties {
     #[serde(rename = "gcs.bucket_name")]
     pub bucket_name: String,
+
+    /// The base64 encoded credential key. If not set, ADC will be used.
     #[serde(rename = "gcs.credential")]
     pub credential: Option<String>,
+
+    /// If credential/ADC is not set. The service account can be used to provide the credential info.
     #[serde(rename = "gcs.service_account", default)]
     pub service_account: Option<String>,
+
     #[serde(rename = "match_pattern", default)]
     pub match_pattern: Option<String>,
 
@@ -107,7 +112,7 @@ pub struct OpendalS3Properties {
     #[serde(flatten)]
     pub s3_properties: S3PropertiesCommon,
 
-    // The following are only supported by s3_v2 (opendal) source.
+    /// The following are only supported by s3_v2 (opendal) source.
     #[serde(rename = "s3.assume_role", default)]
     pub assume_role: Option<String>,
 
@@ -131,11 +136,11 @@ impl SourceProperties for OpendalS3Properties {
 
 #[derive(Clone, Debug, Deserialize, PartialEq, WithOptions)]
 pub struct PosixFsProperties {
-    // The root directly of the files to search. The files will be searched recursively.
+    /// The root directly of the files to search. The files will be searched recursively.
     #[serde(rename = "posix_fs.root")]
     pub root: String,
 
-    // The regex pattern to match files under root directory.
+    /// The regex pattern to match files under root directory.
     #[serde(rename = "match_pattern", default)]
     pub match_pattern: Option<String>,