diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0c12109..b4bd0c9 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -21,9 +21,10 @@ jobs:
       - name: Lint
         run: buf lint
 
+      - name: Fetch main branch for comparison
+        if: github.event_name == 'pull_request'
+        run: git fetch origin main
+
       - name: Breaking change detection
         if: github.event_name == 'pull_request'
-        # Allowed to fail until main has a lint-passing baseline.
-        # Remove continue-on-error once this PR merges.
-        continue-on-error: true
-        run: buf breaking --against .git#branch=main
+        run: buf breaking --against .git#branch=origin/main