diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a522f28..8dace35 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,6 +1,16 @@
 name: CI
 
-on: [push, pull_request]
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+# In-repo branches (e.g. Dependabot's) would otherwise trigger an identical run
+# for both the push and the pull_request event. Those duplicates race each other
+# for the VS Code download, which has caused throttling failures.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 
 jobs:
   build:
diff --git a/src/test/runTest.ts b/src/test/runTest.ts
index e5ac133..93975d3 100644
--- a/src/test/runTest.ts
+++ b/src/test/runTest.ts
@@ -16,7 +16,7 @@ async function main() {
     await runTests({ extensionDevelopmentPath, extensionTestsPath });
   } catch (err) {
     // eslint-disable-next-line no-console
-    console.error("Failed to run tests");
+    console.error("Failed to run tests", err);
     process.exit(1);
   }
 }