diff --git a/.gitea/workflows/validate.yml b/.gitea/workflows/validate.yml
index b9f575f..9b99aee 100644
--- a/.gitea/workflows/validate.yml
+++ b/.gitea/workflows/validate.yml
@@ -2,7 +2,12 @@
 # matches the typed contract in dora-node.yml, and the node's own tests pass.
 name: validate
 
-on: [push, pull_request]
+# A pull request would otherwise run this twice on the same commit: once for
+# the branch push and once for the PR.
+on:
+  push:
+    branches: [main]
+  pull_request:
 
 env:
   DORA_VERSION: v1.0.1