diff --git a/.github/actions/trigger-coolify-deploy/action.yml b/.github/actions/trigger-coolify-deploy/action.yml
index 969d7e4..596bcb0 100644
--- a/.github/actions/trigger-coolify-deploy/action.yml
+++ b/.github/actions/trigger-coolify-deploy/action.yml
@@ -182,11 +182,13 @@ runs:
             phantom_uuid=$(printf '%s' "$phantom" | jq -r '.deployment_uuid')
             phantom_status=$(printf '%s' "$phantom" | jq -r '.status')
 
-            # deployment_uuid comes from the Coolify API response — validate its shape
+            # phantom_uuid comes from the Coolify API response — validate its shape
             # before using it in a URL or SSH command, in case Coolify ever returns
-            # something malformed.
-            if ! printf '%s' "$phantom_uuid" | grep -qiE '^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$'; then
-              echo "  WARNING: unexpected deployment_uuid format '${phantom_uuid}', skipping"
+            # something malformed. Accepts both the legacy UUID format and Coolify's
+            # newer nanoid-style ids (e.g. j9rlp1cg3qdsuqi8sqsvykpo). Uses a bash regex
+            # match (not grep) so ^...$ anchors the whole string, not per-line.
+            if ! [[ "$phantom_uuid" =~ ^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}|[0-9a-z]{20,30})$ ]]; then
+              echo "  WARNING: unexpected phantom_uuid format '${phantom_uuid}', skipping"
               continue
             fi
 
diff --git a/.github/actions/trigger-coolify-deploy/tests/deployment_uuid_format.sh b/.github/actions/trigger-coolify-deploy/tests/deployment_uuid_format.sh
new file mode 100755
index 0000000..f4ee2fd
--- /dev/null
+++ b/.github/actions/trigger-coolify-deploy/tests/deployment_uuid_format.sh
@@ -0,0 +1,33 @@
+#!/usr/bin/env bash
+# Regression test for the deployment_uuid/phantom_uuid format check in action.yml
+# (cancel_phantom_builds). Keeps this in sync with the regex at that call site —
+# if you change one, change both.
+set -euo pipefail
+
+PATTERN='^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}|[0-9a-z]{20,30})$'
+
+check() {
+  local value="$1" expect="$2" label="$3" actual
+  if [[ "$value" =~ $PATTERN ]]; then
+    actual=accept
+  else
+    actual=reject
+  fi
+  if [ "$actual" != "$expect" ]; then
+    echo "FAIL: $label — expected $expect, got $actual for '${value}'"
+    exit 1
+  fi
+  echo "ok: $label"
+}
+
+check "a1b2c3d4-e5f6-7890-abcd-ef1234567890" accept "legacy UUID"
+check "A1B2C3D4-E5F6-7890-ABCD-EF1234567890" accept "legacy UUID, uppercase"
+check "j9rlp1cg3qdsuqi8sqsvykpo" accept "Coolify nanoid-style id (24 chars)"
+check "abcdefghijklmnopqrst" accept "nanoid-style id, 20 chars (lower bound)"
+check "abcdefghijklmnopqrstuvwxyzabcd" accept "nanoid-style id, 30 chars (upper bound)"
+check "not a valid id!" reject "garbage with spaces/punctuation"
+check "" reject "empty string"
+check "abc123" reject "too short to be a nanoid"
+check "abcdefghijklmnopqrstuvwxyzabcde" reject "31 chars, over the bound"
+
+echo "All deployment_uuid format checks passed."
diff --git a/.github/workflows/test-actions.yml b/.github/workflows/test-actions.yml
new file mode 100644
index 0000000..b143500
--- /dev/null
+++ b/.github/workflows/test-actions.yml
@@ -0,0 +1,16 @@
+name: Test actions
+
+on:
+  push:
+    branches: [main, master]
+  pull_request:
+
+jobs:
+  trigger-coolify-deploy-tests:
+    name: trigger-coolify-deploy shell tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+
+      - name: Run deployment_uuid format tests
+        run: bash .github/actions/trigger-coolify-deploy/tests/deployment_uuid_format.sh