diff --git a/bin/compile b/bin/compile
index 14c677de..48790274 100755
--- a/bin/compile
+++ b/bin/compile
@@ -18,22 +18,19 @@ chmod +x "${DATADOG_DIR}/scripts/update_agent_config.sh"
 cp "${ROOT_DIR}/lib/scripts/get_tags.rb" "${DATADOG_DIR}/scripts/get_tags.rb"
 
 
-RUBY_CMD=ruby
+RUBY_CMD=$DEPS_DIR/$DEPS_IDX/bin/ruby
 
-# install ruby if needed (the case of cflinuxfs4 or custom stacks)
-if ! which ruby > /dev/null; then
+# Install the bundled Ruby for our scripts. Always done so the buildpack
+# stops relying on the app's Ruby (which may not exist, or may be a
+# different version on the chained ruby_buildpack).
+if [ ! -x "${RUBY_CMD}" ]; then
   echo "Installing Ruby"
   tar -xzf "${ROOT_DIR}/lib/ruby_3.4.7.tgz" -C "$DEPS_DIR/$DEPS_IDX" && echo "Ruby Install finished"
-  export PATH=$PATH:/home/vcap/deps/$DEPS_IDX/bin
-  RUBY_CMD=$DEPS_DIR/$DEPS_IDX/bin/ruby
 fi
 
-# create a .global_env file to be sourced by external scripts
-# for now, it appends the buildpack deps/bin folder to the PATH env variable of the caller
-# this is needed for stacks where ruby is not installed since our scripts rely on it
-echo "if ! which ruby > /dev/null; then
-  export PATH=\$PATH:/home/vcap/deps/$DEPS_IDX/bin
-fi" > "$DATADOG_DIR/.global_env"
+# Expose the bundled Ruby to runtime scripts via an absolute path rather
+# than mutating PATH, so we don't shadow the app's own ruby/gem/bundle.
+echo "export DD_RUBY=/home/vcap/deps/$DEPS_IDX/bin/ruby" > "$DATADOG_DIR/.global_env"
 
 # for subsquent buildpacks and for buildpack metadata detection
 echo "config: {}
diff --git a/bin/supply b/bin/supply
index 14c677de..48790274 100755
--- a/bin/supply
+++ b/bin/supply
@@ -18,22 +18,19 @@ chmod +x "${DATADOG_DIR}/scripts/update_agent_config.sh"
 cp "${ROOT_DIR}/lib/scripts/get_tags.rb" "${DATADOG_DIR}/scripts/get_tags.rb"
 
 
-RUBY_CMD=ruby
+RUBY_CMD=$DEPS_DIR/$DEPS_IDX/bin/ruby
 
-# install ruby if needed (the case of cflinuxfs4 or custom stacks)
-if ! which ruby > /dev/null; then
+# Install the bundled Ruby for our scripts. Always done so the buildpack
+# stops relying on the app's Ruby (which may not exist, or may be a
+# different version on the chained ruby_buildpack).
+if [ ! -x "${RUBY_CMD}" ]; then
   echo "Installing Ruby"
   tar -xzf "${ROOT_DIR}/lib/ruby_3.4.7.tgz" -C "$DEPS_DIR/$DEPS_IDX" && echo "Ruby Install finished"
-  export PATH=$PATH:/home/vcap/deps/$DEPS_IDX/bin
-  RUBY_CMD=$DEPS_DIR/$DEPS_IDX/bin/ruby
 fi
 
-# create a .global_env file to be sourced by external scripts
-# for now, it appends the buildpack deps/bin folder to the PATH env variable of the caller
-# this is needed for stacks where ruby is not installed since our scripts rely on it
-echo "if ! which ruby > /dev/null; then
-  export PATH=\$PATH:/home/vcap/deps/$DEPS_IDX/bin
-fi" > "$DATADOG_DIR/.global_env"
+# Expose the bundled Ruby to runtime scripts via an absolute path rather
+# than mutating PATH, so we don't shadow the app's own ruby/gem/bundle.
+echo "export DD_RUBY=/home/vcap/deps/$DEPS_IDX/bin/ruby" > "$DATADOG_DIR/.global_env"
 
 # for subsquent buildpacks and for buildpack metadata detection
 echo "config: {}
diff --git a/lib/run-datadog.sh b/lib/run-datadog.sh
index d87e0451..e73e149e 100644
--- a/lib/run-datadog.sh
+++ b/lib/run-datadog.sh
@@ -17,7 +17,7 @@ DD_RUN_AGENT="${DD_RUN_AGENT:-true}"
 # source updated PATH
 . "$DATADOG_DIR/.global_env"
 
-export DD_TAGS=$(ruby "${DATADOG_DIR}/scripts/get_tags.rb")
+export DD_TAGS=$("$DD_RUBY" "${DATADOG_DIR}/scripts/get_tags.rb")
 echo "${DD_TAGS}" > "${DATADOG_DIR}/.dd_tags.txt"
 
 setup_datadog() {
@@ -45,7 +45,7 @@ setup_datadog() {
     if [ -n "${LOGS_CONFIG:-}" ]; then
       mkdir -p "${LOGS_CONFIG_DIR}"
       echo "creating logs config"
-      ruby "${DATADOG_DIR}/scripts/create_logs_config.rb"
+      "$DD_RUBY" "${DATADOG_DIR}/scripts/create_logs_config.rb"
     fi
 
     # The yaml file requires the tags to be an array,
@@ -111,7 +111,7 @@ setup_datadog() {
   popd
 
   # update datadog config
-  ruby "${DATADOG_DIR}/scripts/update_datadog_config.rb"
+  "$DD_RUBY" "${DATADOG_DIR}/scripts/update_datadog_config.rb"
 
   # mark the script as finished, useful to sync the update_agent_config script
   touch "${DATADOG_DIR}/.setup_completed"
@@ -119,7 +119,7 @@ setup_datadog() {
 }
 
 start_datadog() {
-  export DD_TAGS=$(ruby "${DATADOG_DIR}/scripts/get_tags.rb")
+  export DD_TAGS=$("$DD_RUBY" "${DATADOG_DIR}/scripts/get_tags.rb")
 
   pushd "${DATADOG_DIR}"
     export DD_LOG_FILE="${DATADOG_DIR}/dogstatsd.log"
diff --git a/lib/scripts/update_agent_config.sh b/lib/scripts/update_agent_config.sh
index 2508735d..96cdbdae 100644
--- a/lib/scripts/update_agent_config.sh
+++ b/lib/scripts/update_agent_config.sh
@@ -17,23 +17,23 @@ release_lock() {
 }
 
 write_tags_to_file() {
-    export DD_TAGS=$(ruby "${DATADOG_DIR}"/scripts/get_tags.rb)
+    export DD_TAGS=$("$DD_RUBY" "${DATADOG_DIR}"/scripts/get_tags.rb)
 
     export LOGS_CONFIG_DIR="${DATADOG_DIR}/dist/conf.d/logs.d"
     export LOGS_CONFIG
 
     log_info "Updating node_agent_tags.txt"
-    ruby "${DATADOG_DIR}/scripts/update_tags.rb"
+    "$DD_RUBY" "${DATADOG_DIR}/scripts/update_tags.rb"
 
     # update datadog config
-    ruby "${DATADOG_DIR}/scripts/update_datadog_config.rb"
+    "$DD_RUBY" "${DATADOG_DIR}/scripts/update_datadog_config.rb"
 
     if [ "${DD_ENABLE_CAPI_METADATA_COLLECTION}" = "true" ]; then
         # update logs configs
         if [ -n "${LOGS_CONFIG}" ]; then
             mkdir -p "${LOGS_CONFIG_DIR}"
             log_info "Updating logs config"
-            ruby "${DATADOG_DIR}/scripts/create_logs_config.rb"
+            "$DD_RUBY" "${DATADOG_DIR}/scripts/create_logs_config.rb"
         fi
     fi
 
diff --git a/lib/scripts/utils.sh b/lib/scripts/utils.sh
index f9779fcb..a57b5b7f 100644
--- a/lib/scripts/utils.sh
+++ b/lib/scripts/utils.sh
@@ -219,7 +219,7 @@ redirect() {
             \"title\": \"Resetting buildpack log redirection\",
             \"text\": \"TCP socket on port ${STD_LOG_COLLECTION_PORT:-} for log redirection closed. Restarting it.\",
             \"priority\": \"normal\",
-            \"tags\": $(LEGACY_TAGS_FORMAT=true ruby "${DATADOG_DIR}/scripts/get_tags.rb"),
+            \"tags\": $(LEGACY_TAGS_FORMAT=true "$DD_RUBY" "${DATADOG_DIR}/scripts/get_tags.rb"),
             \"alert_type\": \"info\"
       }" "${DD_API_SITE:-}v1/events?api_key=${DD_API_KEY:-}"
     fi
diff --git a/lib/test-endpoint.sh b/lib/test-endpoint.sh
index 8d4897e7..41b8607a 100644
--- a/lib/test-endpoint.sh
+++ b/lib/test-endpoint.sh
@@ -73,7 +73,7 @@ if [ "${DD_LOGS_ENABLED:-}" = "true" ] && [ -n "${DD_LOGS_CONFIG_LOGS_DD_URL}" ]
             \"title\": \"Log endpoint cannot be reached - Log collection not started\",
             \"text\": \"Could not establish a connection to ${DD_LOGS_CONFIG_LOGS_DD_URL} after 5 seconds. Log collection has not been started.\",
             \"priority\": \"normal\",
-            \"tags\": $(ruby "${DATADOG_DIR}"/scripts/get_tags.rb),
+            \"tags\": $("$DD_RUBY" "${DATADOG_DIR}"/scripts/get_tags.rb),
             \"alert_type\": \"error\"
       }" "api.${DD_SITE:-}/v1/events?api_key=${DD_API_KEY:-}"
   else