diff --git a/.github/workflows/pr-ai-review.yml b/.github/workflows/pr-ai-review.yml
index 26878d7a1..c1e908a3e 100644
--- a/.github/workflows/pr-ai-review.yml
+++ b/.github/workflows/pr-ai-review.yml
@@ -18,7 +18,10 @@ permissions:
 jobs:
   authorize:
     runs-on: ubuntu-latest
-    if: github.event_name == 'workflow_dispatch' || github.event_name == 'pull_request_target'
+    # explicitly require the PR to be open to avoid old events triggering a review on closed PRs: https://github.com/aws/agentcore-cli/issues/1463
+    if:
+      github.event_name == 'workflow_dispatch' || (github.event_name == 'pull_request_target' &&
+      github.event.pull_request.state == 'open')
     outputs:
       authorized: ${{ steps.auth.outputs.authorized }}
     steps: