diff --git a/.github/workflows/matrix-bridge-ci.yml b/.github/workflows/matrix-bridge-ci.yml
new file mode 100644
index 00000000..9bc3094c
--- /dev/null
+++ b/.github/workflows/matrix-bridge-ci.yml
@@ -0,0 +1,70 @@
+name: Matrix Bridge CI
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'replicas-matrix-bridge/**'
+      - '.github/workflows/matrix-bridge-ci.yml'
+  pull_request:
+    paths:
+      - 'replicas-matrix-bridge/**'
+      - '.github/workflows/matrix-bridge-ci.yml'
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: replicas-matrix-bridge
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+      - name: Install dependencies
+        run: npm ci
+      - name: Typecheck
+        run: npm run typecheck
+      - name: Test
+        run: npm test
+
+  auth-gate-smoke-test:
+    name: Auth gate smoke test
+    runs-on: ubuntu-latest
+    needs: test
+    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+    steps:
+      - name: Assert /admin/listener/reset returns 401 without ADMIN_TOKEN
+        run: |
+          STATUS=$(curl -s -o /dev/null -w "%{http_code}" \
+            -X POST https://replicas-matrix-bridge.jadengarza.workers.dev/admin/listener/reset)
+          echo "no-auth status: $STATUS"
+          if [ "$STATUS" != "401" ]; then
+            echo "❌ /admin/listener/reset returned $STATUS without auth (expected 401)"
+            echo "The ADMIN_TOKEN gate has regressed — every admin/debug endpoint is exposed."
+            exit 1
+          fi
+          echo "✅ Auth gate is enforced on /admin/* endpoints"
+
+      - name: Assert /debug/listener returns 401 without ADMIN_TOKEN
+        run: |
+          STATUS=$(curl -s -o /dev/null -w "%{http_code}" \
+            -X GET https://replicas-matrix-bridge.jadengarza.workers.dev/debug/listener)
+          echo "no-auth status: $STATUS"
+          if [ "$STATUS" != "401" ]; then
+            echo "❌ /debug/listener returned $STATUS without auth (expected 401)"
+            exit 1
+          fi
+          echo "✅ Auth gate is enforced on /debug/* endpoints"
+
+      - name: Assert /health stays public (no auth required)
+        run: |
+          STATUS=$(curl -s -o /dev/null -w "%{http_code}" \
+            -X GET https://replicas-matrix-bridge.jadengarza.workers.dev/health)
+          echo "/health status: $STATUS"
+          if [ "$STATUS" != "200" ]; then
+            echo "❌ /health returned $STATUS (expected 200 — must stay public for uptime checks)"
+            exit 1
+          fi
+          echo "✅ /health is public"