diff --git a/Jenkins/Phabricator-pipeline/Jenkinsfile b/Jenkins/Phabricator-pipeline/Jenkinsfile
index 48b8a2b..2d027ef 100644
--- a/Jenkins/Phabricator-pipeline/Jenkinsfile
+++ b/Jenkins/Phabricator-pipeline/Jenkinsfile
@@ -18,6 +18,9 @@ pipeline {
         string(name: 'DIFF_ID')
         string(name: 'PHID')
     }
+    environment {
+            CONDUIT_TOKEN = credentials('phabricator-conduit-token')
+    }
     stages {
         stage("git checkout"){
             steps {
@@ -31,7 +34,7 @@ pipeline {
         }
         stage('arc patch') {
             steps {
-                echo 'TODO: arc patch'
+                sh 'llvm-premerge-checks/scripts/phabtalk/apply_patch.py --host="https://reviews.llvm.org" --conduit-token="${CONDUIT_TOKEN}"'
             }
         }
         stage('CMake') {
diff --git a/scripts/phabtalk/README.md b/scripts/phabtalk/README.md
new file mode 100644
index 0000000..8005744
--- /dev/null
+++ b/scripts/phabtalk/README.md
@@ -0,0 +1,2 @@
+This folder contains Python scripts that to Phabricator.
+They require a few libraries listed in `requirements.txt`.
\ No newline at end of file
diff --git a/scripts/phabtalk/apply_patch.py b/scripts/phabtalk/apply_patch.py
new file mode 100755
index 0000000..2d58d55
--- /dev/null
+++ b/scripts/phabtalk/apply_patch.py
@@ -0,0 +1,59 @@
+#!/bin/env python3
+# Copyright 2019 Google LLC
+#
+# Licensed under the the Apache License v2.0 with LLVM Exceptions (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://llvm.org/LICENSE.txt
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import argparse
+import os
+import subprocess
+from phabricator import Phabricator
+
+
+def main():
+    args = _parse_args()
+    diff_id = os.environ['DIFF_ID']
+    phid = os.environ['PHID']
+
+    phab = Phabricator(token=args.conduit_token, host=args.host+'/api/')
+    phab.update_interfaces()
+
+    _git_checkout(_get_parent_hash(diff_id, phab))
+    _apply_patch(diff_id, args.conduit_token, args.host)
+
+
+def _get_parent_hash(diff_id: str, phab:Phabricator) -> str:
+    diff = phab.differential.getdiff(diff_id=diff_id)
+    return diff['sourceControlBaseRevision']
+
+def _git_checkout(git_hash:str):
+    subprocess.check_call('git reset --hard {}'.format(git_hash), shell=True)
+    subprocess.check_call('git clean -fdx', shell=True)
+
+def _apply_patch(diff_id: str, conduit_token: str, host: str):
+    cmd = 'arc  patch --nobranch --no-ansi --diff {} --nocommit '\
+            '--conduit-token "{}" --conduit-uri "{}"'.format(
+        diff_id, conduit_token, host )
+    subprocess.call(cmd, shell=True)
+
+
+def _parse_args():
+    parser = argparse.ArgumentParser(description='Apply a phabricator patch.')
+    parser.add_argument('--conduit-token', type=str, dest='conduit_token', default=None)
+    parser.add_argument('--host', type=str, dest='host', default="None", 
+        help="full URL to API with trailing slash, e.g. https://reviews.llvm.org/api/")
+    
+    return parser.parse_args()    
+
+
+if __name__ == "__main__":
+    main()
+