diff --git a/.github/workflows/phep3_email_reminder.yml b/.github/workflows/phep3_email_reminder.yml
index 123bd61..1c0d413 100644
--- a/.github/workflows/phep3_email_reminder.yml
+++ b/.github/workflows/phep3_email_reminder.yml
@@ -13,6 +13,8 @@ on:
 
 jobs:
   send-reminder:
+    # Production email must never be sent from contributor forks.
+    if: github.repository == 'heliophysicsPy/heliophysicsPy.github.io'
     runs-on: ubuntu-latest
 
     steps:
diff --git a/.github/workflows/update_phep3_schedule.yml b/.github/workflows/update_phep3_schedule.yml
index 9e019d4..6161eb5 100644
--- a/.github/workflows/update_phep3_schedule.yml
+++ b/.github/workflows/update_phep3_schedule.yml
@@ -7,6 +7,8 @@ on:
 
 jobs:
   update-schedule:
+    # Generated schedule commits must only be created in the canonical repository.
+    if: github.repository == 'heliophysicsPy/heliophysicsPy.github.io'
     runs-on: ubuntu-latest
 
     steps: