diff --git a/README.md b/README.md
index 9906c87..2f85176 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,7 @@ Configuration is done via env variables
 * `SLACK_BOT_TOKEN` - Slack bot token. Mandatory parameter. scopes: channels:history, chat:write, reactions:read, users:read.email, users:read
 * `SLACK_APP_TOKEN` - Slack app token. Mandatory parameter. scopes: connections:write
 * `SLACK_CHANNEL_NAME` - Slack channel name. Also channel_id can be used
+* `TRIGGERED_BY_EMAIL` - Email of the person who triggered the build, for example by pressing the merge button. Optional parameter. When set, a `Triggered by` line is added to the approval message, mentioning that person if the email matches a Slack profile. Useful because the commit itself does not always point at a person: squash merges on GitHub, for instance, are committed as `noreply@github.com`. A GitHub-generated noreply address (bare `noreply@github.com` or the privacy-enabled `<id>+<username>@users.noreply.github.com` form) never resolves to a person, so the `Triggered by` line is omitted entirely rather than showing that address
 
 # Slack App manifect example 
 ```yaml
diff --git a/helpers_git.py b/helpers_git.py
index bc82d73..4e6c3e2 100644
--- a/helpers_git.py
+++ b/helpers_git.py
@@ -1,6 +1,18 @@
 import subprocess
 import helpers_slack
 
+# GitHub-generated addresses that never resolve to a real Slack profile:
+# noreply@github.com (bare merge/squash commits) and the privacy-enabled
+# form <id>+<username>@users.noreply.github.com (bots, and any user with
+# "Keep my email addresses private" turned on - this is common, not rare).
+NOREPLY_DOMAIN_SUFFIX = '@users.noreply.github.com'
+NOREPLY_BARE_ADDRESS = 'noreply@github.com'
+
+
+def is_noreply_email(email):
+    email = (email or '').strip().lower()
+    return email == NOREPLY_BARE_ADDRESS or email.endswith(NOREPLY_DOMAIN_SUFFIX)
+
 
 def resolve_git_ref_to_sha1(ref_name):
     print(f'Resolving {ref_name} to Git SHA1...')
diff --git a/helpers_slack.py b/helpers_slack.py
index 46dd6c9..a29d2ba 100644
--- a/helpers_slack.py
+++ b/helpers_slack.py
@@ -92,10 +92,12 @@ def user_id_by_email(app, email):
         result = app.client.users_lookupByEmail(email=email)
         return result['user']['id']
     except SlackApiError as err:
-        if err.response['error'] == 'users_not_found':
-            return None
-
-    return None
+        error_code = err.response['error']
+        if error_code == 'users_not_found':
+            print(f'No Slack user found for email {email}')
+        else:
+            print(f'Slack lookup failed for email {email}: {error_code}')
+        return None
 
 
 def is_message_longer_than_limit(message):
diff --git a/main.py b/main.py
index 4185920..8a1bfa7 100644
--- a/main.py
+++ b/main.py
@@ -26,6 +26,9 @@
     timezone = os.environ['TIMEZONE']
     production_branches = os.environ['PRODUCTION_BRANCHES'].split()
     slack_bot_token = os.environ["SLACK_BOT_TOKEN"]
+    # Not every commit is made by a person - squash merges, for instance, are committed by
+    # the SCM itself - so CI can tell us who triggered the build. Optional.
+    triggered_by_email = os.environ.get('TRIGGERED_BY_EMAIL', '')
 
     print(f'branches_to_promote: {branches_to_promote}')
     print(f'production_branches: {production_branches}')
@@ -40,6 +43,13 @@
     author_email = helpers_git.get_author_email_for_ref(current_commit_id)
     author_slack_id = helpers_slack.user_id_by_email(app, author_email)
     author_id = f'<@{author_slack_id}>' if author_slack_id is not None else author_email
+    triggered_by_id = None
+    triggered_by_valid = (triggered_by_email and triggered_by_email.strip()
+                          and not helpers_git.is_noreply_email(triggered_by_email))
+    if triggered_by_valid:
+        triggered_by_slack_id = helpers_slack.user_id_by_email(app, triggered_by_email)
+        triggered_by_id = (f'<@{triggered_by_slack_id}>'
+                           if triggered_by_slack_id is not None else triggered_by_email)
     commit_msg = helpers_git.get_commit_message_for_ref(current_commit_id)
 
     text_for_request = 'If approved will promote commit(s) below to branch '
@@ -49,7 +59,10 @@
     details += f'Commit message: `{commit_msg}`\n'
     details += f'Commit id: `{current_commit_id}`\n'
     details += f'Committer: {commiter_id}\n'
-    details += f'Author: {author_id}\n\n'
+    details += f'Author: {author_id}\n'
+    if triggered_by_id is not None:
+        details += f'Triggered by: {triggered_by_id}\n'
+    details += '\n'
     details += helpers_time.generate_time_based_message(production_branches, branches_to_promote, timezone)
 
     # Generate separate diff blocks for every branch