diff --git a/infra/build/functions/ci_trial_build.py b/infra/build/functions/ci_trial_build.py
index 0359b2a7d..418528e33 100644
--- a/infra/build/functions/ci_trial_build.py
+++ b/infra/build/functions/ci_trial_build.py
@@ -27,6 +27,8 @@ import github
 import trial_build
 
 TRIGGER_COMMAND = '/gcbrun'
+TRIAL_BUILD_COMMAND_STR = f'{TRIGGER_COMMAND} trial_build.py '
+SKIP_COMMAND_STR = f'{TRIGGER_COMMAND} skip'
 
 
 def get_comments(pull_request_number):
@@ -48,12 +50,13 @@ def get_latest_gcbrun_command(comments):
   for comment in reversed(comments):
     # This seems to get comments on code too.
     body = comment.body
-    command_str = f'{TRIGGER_COMMAND} trial_build.py '
-    if not body.startswith(command_str):
-      continue
-    if len(body) == len(command_str):
+    if body.startswith(SKIP_COMMAND_STR):
       return None
-    return body[len(command_str):].strip().split(' ')
+    if not body.startswith(TRIAL_BUILD_COMMAND_STR):
+      continue
+    if len(body) == len(TRIAL_BUILD_COMMAND_STR):
+      return None
+    return body[len(TRIAL_BUILD_COMMAND_STR):].strip().split(' ')
   return None
 
 
@@ -62,11 +65,11 @@ def exec_command_from_github(pull_request_number, repo, branch):
   on |pull_request_number|."""
   comments = get_comments(pull_request_number)
   command = get_latest_gcbrun_command(comments)
-  command.extend(['--repo', repo])
-  logging.info('Command: %s.', command)
   if command is None:
     logging.info('Trial build not requested.')
     return None
+  command.extend(['--repo', repo])
+  logging.info('Command: %s.', command)
 
   # Set the branch so that the trial_build builds the projects from the PR
   # branch.
@@ -81,7 +84,8 @@ def main():
   pull_request_number = int(os.environ['PULL_REQUEST_NUMBER'])
   branch = os.environ['BRANCH']
   repo = os.environ['REPO']
-  if exec_command_from_github(pull_request_number, repo, branch):
+  result = exec_command_from_github(pull_request_number, repo, branch)
+  if result or result is None:
     return 0
   return 1