diff --git a/.github/workflows/copilot-setup-steps.yml b/.github/workflows/copilot-setup-steps.yml
new file mode 100644
index 000000000..ef0b122e1
--- /dev/null
+++ b/.github/workflows/copilot-setup-steps.yml
@@ -0,0 +1,47 @@
+name: "Copilot Agent environment setup"
+
+on:
+  workflow_dispatch:
+  push:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+  pull_request:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+
+jobs:
+  # The job MUST be called `copilot-setup-steps` or it will not be picked up by Copilot.
+  copilot-setup-steps:
+    runs-on: ubuntu-latest
+
+    permissions:
+      contents: read
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup PHP
+        uses: pmmp/setup-php-action@3.2.0
+        with:
+          php-version: 8.3
+          install-path: "./bin"
+          pm-version-major: 5
+
+      - name: Restore Composer package cache
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cache/composer/files
+            ~/.cache/composer/vcs
+          key: "composer-v2-cache-8.3-${{ hashFiles('./composer.lock') }}"
+          restore-keys: |
+            composer-v2-cache-
+
+      - name: Install Composer dependencies
+        run: composer install --prefer-dist --no-interaction
+
+      - name: Clone extension stubs
+        uses: actions/checkout@v4
+        with:
+          repository: pmmp/phpstorm-stubs
+          path: extension-stubs
diff --git a/build/php b/build/php
index 154943379..ce1b095a9 160000
--- a/build/php
+++ b/build/php
@@ -1 +1 @@
-Subproject commit 15494337976e645499e2e3e8c8b491227522be91
+Subproject commit ce1b095a9c6f47dadc7b5812da4e469d52f272bc