diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
index bf4371d5..3562b261 100644
--- a/.devcontainer/devcontainer.json
+++ b/.devcontainer/devcontainer.json
@@ -24,8 +24,11 @@
     "ghcr.io/devcontainers/features/node:1": {
       "version": "14"
     },
-    "ghcr.io/devcontainers/features/docker-in-docker:2": {},
-    "ghcr.io/devcontainers/features/git:1": {}
+    "ghcr.io/devcontainers/features/docker-in-docker:2": {
+      "dockerDashComposeVersion": "v2"
+    },
+    "ghcr.io/devcontainers/features/git:1": {},
+    "ghcr.io/devcontainers/features/github-cli:1": {}
   },
 
   // Use 'forwardPorts' to make a list of ports inside the container available locally.
diff --git a/.devcontainer/install.sh b/.devcontainer/install.sh
new file mode 100644
index 00000000..69c335b2
--- /dev/null
+++ b/.devcontainer/install.sh
@@ -0,0 +1,11 @@
+#!/usr/bin/env sh
+
+set -eux
+
+echo "Installing wp-cli..."
+curl -O https://raw.githubusercontent.com/wp-cli/builds/gh-pages/phar/wp-cli.phar
+sudo chmod +x wp-cli.phar
+sudo mv wp-cli.phar /usr/local/bin/wp
+
+# Copy the welcome message
+sudo cp .devcontainer/welcome-message.txt /usr/local/etc/vscode-dev-containers/first-run-notice.txt
diff --git a/.devcontainer/setup.sh b/.devcontainer/setup.sh
new file mode 100644
index 00000000..bad0f172
--- /dev/null
+++ b/.devcontainer/setup.sh
@@ -0,0 +1,24 @@
+#!/usr/bin/env sh
+
+set -eux
+
+if [ -z ${CODESPACE_NAME+x} ]; then
+	SITE_HOST="http://localhost:8080"
+else
+	SITE_HOST="https://${CODESPACE_NAME}-8080.${GITHUB_CODESPACES_PORT_FORWARDING_DOMAIN}"
+fi
+
+PLUGIN_DIR=/workspaces/openid-connect-generic
+
+# Install Composer dependencies.
+cd "${PLUGIN_DIR}"
+composer install
+
+# Install Composer dependencies.
+cd "${PLUGIN_DIR}"
+npm ci
+
+# Setup the WordPress environment.
+cd /var/www/html
+echo "Setting up WordPress at $SITE_HOST"
+wp core install --url="$SITE_HOST" --title="WordPress Trunk" --admin_user="admin" --admin_email="admin@example.com" --admin_password="password" --skip-email
diff --git a/.devcontainer/welcome-message.txt b/.devcontainer/welcome-message.txt
new file mode 100644
index 00000000..5b7bf05e
--- /dev/null
+++ b/.devcontainer/welcome-message.txt
@@ -0,0 +1,6 @@
+👋 Welcome to "OpenID Connect for WP Development" in Codespaces!
+
+🛠️  Your environment is fully setup with all the required software.
+
+🚀 To get started, wait for the "postCreateCommand" to finish setting things up, then open the portforwarded URL and append '/wp-admin'.
+
diff --git a/dev-cli b/dev-cli
new file mode 100755
index 00000000..be5df668
--- /dev/null
+++ b/dev-cli
@@ -0,0 +1,32 @@
+#!/usr/bin/env sh
+## Description: Run local development commands.
+## Usage: ./dev-cli [flags] [command]
+## Example: "./dev-cli phpcs"
+
+WORKSPACE_DIR=./
+
+# Check for the devcontainer CLI.
+# TODO: Add a devcontainer CLI check and provide a docker compose fallback.
+
+case $1 in
+	build)
+		devcontainer --workspace-folder ${WORKSPACE_DIR} build "${@:2}"
+	;;
+	start)
+		devcontainer --workspace-folder ${WORKSPACE_DIR} up "${@:2}"
+	;;
+	composer)
+		devcontainer exec --workspace-folder ${WORKSPACE_DIR} composer "${@:2}"
+	;;
+	npm)
+		devcontainer exec --workspace-folder ${WORKSPACE_DIR} npm "${@:2}"
+	;;
+	phpcs|phpcbf|phpstan|phpunit)
+		devcontainer exec --workspace-folder ${WORKSPACE_DIR} composer "$@"
+	;;
+	"")
+		echo "Usage: ./dev-cli [flags] [command]"
+	;;
+	*)
+	;;
+esac
diff --git a/docker-compose.yml b/docker-compose.yml
index fa528d5c..6ef82d68 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -7,7 +7,7 @@ services:
   app:
     image: wordpressdevelop/php:8.0-fpm
     restart: always
-    working_dir: /var/www/html
+    working_dir: /app
     depends_on:
       - db
     environment:
@@ -16,10 +16,7 @@ services:
       WORDPRESS_DB_USER: wordpress_test
       WORDPRESS_DB_PASSWORD: wordpress_test
     volumes:
-      - ./wordpress:/var/www/html/wp:cached
-      - .:/var/www/html/wp-content/plugins/daggerhart-openid-connect-generic:cached
-      - ./tools/local-env/mu-plugins:/var/www/html/wp-content/mu-plugins:cached
-      - ./tools/local-env/wp-config.dev.php:/var/www/html/wp-config.php:cached
+      - ../..:/workspaces:cached
       - ~/.composer:/root/.composer:cached
     networks:
       - oidcwp-net
@@ -38,10 +35,8 @@ services:
       WORDPRESS_DB_USER: wordpress
       WORDPRESS_DB_PASSWORD: wordpress
     volumes:
-      - ./wordpress:/var/www/html/wp:cached
-      - .:/var/www/html/wp-content/plugins/daggerhart-openid-connect-generic:cached
-      - ./tools/local-env/mu-plugins:/var/www/html/wp-content/mu-plugins:cached
-      - ./tools/local-env/wp-config.dev.php:/var/www/html/wp-config.php:cached
+      - ./tools/local-env:/var/www/html:cached
+      - .:/var/www/html/wp-content/plugins/daggerhart-openid-connect-generic:cached,ro
     networks:
       - oidcwp-net
 
diff --git a/tools/local-env/phpunit-wp-config.php b/tools/local-env/phpunit-wp-config.php
deleted file mode 100644
index 556672df..00000000
--- a/tools/local-env/phpunit-wp-config.php
+++ /dev/null
@@ -1,133 +0,0 @@
-<?php
-/**
- * The base configuration for WordPress
- *
- * The wp-config.php creation script uses this file during the
- * installation. You don't have to use the web site, you can
- * copy this file to "wp-config.php" and fill in the values.
- *
- * This file contains the following configurations:
- *
- * * MySQL settings
- * * Secret keys
- * * Database table prefix
- * * ABSPATH
- *
- * This has been slightly modified (to read environment variables) for use in Docker.
- *
- * @link https://wordpress.org/support/article/editing-wp-config-php/
- *
- * @package WordPress
- */
-
-// IMPORTANT: this file needs to stay in-sync with https://github.com/WordPress/WordPress/blob/master/wp-config-sample.php
-// (it gets parsed by the upstream wizard in https://github.com/WordPress/WordPress/blob/f27cb65e1ef25d11b535695a660e7282b98eb742/wp-admin/setup-config.php#L356-L392)
-
-// a helper function to lookup "env_FILE", "env", then fallback
-function getenv_docker($env, $default) {
-	if ($fileEnv = getenv($env . '_FILE')) {
-		return rtrim(file_get_contents($fileEnv), "\r\n");
-	}
-	else if (($val = getenv($env)) !== false) {
-		return $val;
-	}
-	else {
-		return $default;
-	}
-}
-
-// ** MySQL settings - You can get this info from your web host ** //
-/** The name of the database for WordPress */
-define( 'DB_NAME', getenv_docker('WORDPRESS_DB_NAME', 'wordpress') );
-
-/** MySQL database username */
-define( 'DB_USER', getenv_docker('WORDPRESS_DB_USER', 'root') );
-
-/** MySQL database password */
-define( 'DB_PASSWORD', getenv_docker('WORDPRESS_DB_PASSWORD', '') );
-
-/**
- * Docker image fallback values above are sourced from the official WordPress installation wizard:
- * https://github.com/WordPress/WordPress/blob/f9cc35ebad82753e9c86de322ea5c76a9001c7e2/wp-admin/setup-config.php#L216-L230
- * (However, using "example username" and "example password" in your database is strongly discouraged.  Please use strong, random credentials!)
- */
-
-/** MySQL hostname */
-define( 'DB_HOST', getenv_docker('WORDPRESS_DB_HOST', 'mysql') );
-
-/** Database Charset to use in creating database tables. */
-define( 'DB_CHARSET', getenv_docker('WORDPRESS_DB_CHARSET', 'utf8') );
-
-/** The Database Collate type. Don't change this if in doubt. */
-define( 'DB_COLLATE', getenv_docker('WORDPRESS_DB_COLLATE', '') );
-
-/**#@+
- * Authentication Unique Keys and Salts.
- *
- * Change these to different unique phrases!
- * You can generate these using the {@link https://api.wordpress.org/secret-key/1.1/salt/ WordPress.org secret-key service}
- * You can change these at any point in time to invalidate all existing cookies. This will force all users to have to log in again.
- *
- * @since 2.6.0
- */
-define( 'AUTH_KEY',         getenv_docker('WORDPRESS_AUTH_KEY',         '96f6bcee44eacbd3e9a5c3c78f52d615bbe550f1') );
-define( 'SECURE_AUTH_KEY',  getenv_docker('WORDPRESS_SECURE_AUTH_KEY',  'cd0555ee6a32c91e064a499ebb3fd5ceea62e2a3') );
-define( 'LOGGED_IN_KEY',    getenv_docker('WORDPRESS_LOGGED_IN_KEY',    '34b7c03618d67a8d626cd5c78508adfe542e6349') );
-define( 'NONCE_KEY',        getenv_docker('WORDPRESS_NONCE_KEY',        '848d7098eb38eca67857d6e0ee5b3fba5962c7c1') );
-define( 'AUTH_SALT',        getenv_docker('WORDPRESS_AUTH_SALT',        '881a5f5689e7c265b8dd8c6ae4fdff54888e06fa') );
-define( 'SECURE_AUTH_SALT', getenv_docker('WORDPRESS_SECURE_AUTH_SALT', '2275b260e683602a91c8d19f6a05a6362bd5a91f') );
-define( 'LOGGED_IN_SALT',   getenv_docker('WORDPRESS_LOGGED_IN_SALT',   '7cf0086a484ed4eabd1ce1b09a6a59a11297c61f') );
-define( 'NONCE_SALT',       getenv_docker('WORDPRESS_NONCE_SALT',       '2fc8e8507b204f6e69e2c750a5ceaed9f5951736') );
-// (See also https://wordpress.stackexchange.com/a/152905/199287)
-
-/**#@-*/
-
-/**
- * WordPress Database Table prefix.
- *
- * You can have multiple installations in one database if you give each
- * a unique prefix. Only numbers, letters, and underscores please!
- */
-$table_prefix = getenv_docker('WORDPRESS_TABLE_PREFIX', 'wp_');
-
-/**
- * For developers: WordPress debugging mode.
- *
- * Change this to true to enable the display of notices during development.
- * It is strongly recommended that plugin and theme developers use WP_DEBUG
- * in their development environments.
- *
- * For information on other constants that can be used for debugging,
- * visit the documentation.
- *
- * @link https://wordpress.org/support/article/debugging-in-wordpress/
- */
-define( 'WP_DEBUG', true );
-
-// If we're behind a proxy server and using HTTPS, we need to alert WordPress of that fact
-// see also http://codex.wordpress.org/Administration_Over_SSL#Using_a_Reverse_Proxy
-if (isset($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] === 'https') {
-	$_SERVER['HTTPS'] = 'on';
-}
-// (we include this by default because reverse proxying is extremely common in container environments)
-
-if ($configExtra = getenv_docker('WORDPRESS_CONFIG_EXTRA', '')) {
-	eval($configExtra);
-}
-
-define( 'PHP_INI_MEMORY_LIMIT', '512M' );
-define( 'WP_MEMORY_LIMIT', '512M' );
-define( 'WP_DEBUG_LOG', true );
-define( 'WP_DEBUG_DISPLAY', true );
-define( 'SCRIPT_DEBUG', true );
-define( 'SMTP_HOST', 'mailhog' );
-define( 'SMTP_PORT', 1025 );
-define( 'WP_TESTS_DOMAIN', 'localhost:8889' );
-/* That's all, stop editing! Happy publishing. */
-
-/** Absolute path to the WordPress directory. */
-if ( ! defined( 'ABSPATH' ) ) {
-	define( 'ABSPATH', __DIR__ . '/' );
-}
-
-/** Sets up WordPress vars and included files. */
diff --git a/tools/local-env/wp-config.dev.php b/tools/local-env/wp-config.php
similarity index 100%
rename from tools/local-env/wp-config.dev.php
rename to tools/local-env/wp-config.php
diff --git a/tools/local-env/wp-config.tests.php b/tools/local-env/wp-config.tests.php
deleted file mode 100644
index 4bb9e2d9..00000000
--- a/tools/local-env/wp-config.tests.php
+++ /dev/null
@@ -1,247 +0,0 @@
-<?php
-
-/**
-
- * The base configuration for WordPress
-
- *
-
- * The wp-config.php creation script uses this file during the
-
- * installation. You don't have to use the web site, you can
-
- * copy this file to "wp-config.php" and fill in the values.
-
- *
-
- * This file contains the following configurations:
-
- *
-
- * * MySQL settings
-
- * * Secret keys
-
- * * Database table prefix
-
- * * ABSPATH
-
- *
-
- * This has been slightly modified (to read environment variables) for use in Docker.
-
- *
-
- * @link https://wordpress.org/support/article/editing-wp-config-php/
-
- *
-
- * @package WordPress
-
- */
-
-
-// IMPORTANT: this file needs to stay in-sync with https://github.com/WordPress/WordPress/blob/master/wp-config-sample.php
-
-// (it gets parsed by the upstream wizard in https://github.com/WordPress/WordPress/blob/f27cb65e1ef25d11b535695a660e7282b98eb742/wp-admin/setup-config.php#L356-L392)
-
-
-// a helper function to lookup "env_FILE", "env", then fallback
-
-function getenv_docker($env, $default) {
-
-	if ($fileEnv = getenv($env . '_FILE')) {
-
-		return rtrim(file_get_contents($fileEnv), "\r\n");
-
-	}
-
-	else if (($val = getenv($env)) !== false) {
-
-		return $val;
-
-	}
-
-	else {
-
-		return $default;
-
-	}
-
-}
-
-
-// ** MySQL settings - You can get this info from your web host ** //
-
-/** The name of the database for WordPress */
-
-define( 'DB_NAME', getenv_docker('WORDPRESS_DB_NAME', 'tests-wordpress') );
-
-
-/** MySQL database username */
-
-define( 'DB_USER', getenv_docker('WORDPRESS_DB_USER', 'root') );
-
-
-/** MySQL database password */
-
-define( 'DB_PASSWORD', getenv_docker('WORDPRESS_DB_PASSWORD', '') );
-
-
-/**
-
- * Docker image fallback values above are sourced from the official WordPress installation wizard:
-
- * https://github.com/WordPress/WordPress/blob/f9cc35ebad82753e9c86de322ea5c76a9001c7e2/wp-admin/setup-config.php#L216-L230
-
- * (However, using "example username" and "example password" in your database is strongly discouraged.  Please use strong, random credentials!)
-
- */
-
-
-/** MySQL hostname */
-
-define( 'DB_HOST', getenv_docker('WORDPRESS_DB_HOST', 'mysql') );
-
-
-/** Database Charset to use in creating database tables. */
-
-define( 'DB_CHARSET', getenv_docker('WORDPRESS_DB_CHARSET', 'utf8') );
-
-
-/** The Database Collate type. Don't change this if in doubt. */
-
-define( 'DB_COLLATE', getenv_docker('WORDPRESS_DB_COLLATE', '') );
-
-
-/**#@+
-
- * Authentication Unique Keys and Salts.
-
- *
-
- * Change these to different unique phrases!
-
- * You can generate these using the {@link https://api.wordpress.org/secret-key/1.1/salt/ WordPress.org secret-key service}
-
- * You can change these at any point in time to invalidate all existing cookies. This will force all users to have to log in again.
-
- *
-
- * @since 2.6.0
-
- */
-
-define( 'AUTH_KEY',         getenv_docker('WORDPRESS_AUTH_KEY',         '755ef358c5a27ed0dc746d9787d4921218514caf') );
-
-define( 'SECURE_AUTH_KEY',  getenv_docker('WORDPRESS_SECURE_AUTH_KEY',  '2ab5c46490b1f076010c19e6d2f13e5af9357ee9') );
-
-define( 'LOGGED_IN_KEY',    getenv_docker('WORDPRESS_LOGGED_IN_KEY',    'f7701c9a21f9f13dde7f0098325050c3a5cb8265') );
-
-define( 'NONCE_KEY',        getenv_docker('WORDPRESS_NONCE_KEY',        'f6b4c843e5d2c4b8d9d9c68d0509d6da03b79986') );
-
-define( 'AUTH_SALT',        getenv_docker('WORDPRESS_AUTH_SALT',        '93b47cee7f7afb7d6a91ec224e705b0eac0fc9f0') );
-
-define( 'SECURE_AUTH_SALT', getenv_docker('WORDPRESS_SECURE_AUTH_SALT', '59c8f022ed0da0fe3cb9e33090f11d4d141d6031') );
-
-define( 'LOGGED_IN_SALT',   getenv_docker('WORDPRESS_LOGGED_IN_SALT',   'c30efb00b0252d2fd709d212792a27bc6a279f73') );
-
-define( 'NONCE_SALT',       getenv_docker('WORDPRESS_NONCE_SALT',       '4e56339167a14453a3b4044f9eaa3735a1a368f0') );
-
-// (See also https://wordpress.stackexchange.com/a/152905/199287)
-
-
-/**#@-*/
-
-
-/**
-
- * WordPress Database Table prefix.
-
- *
-
- * You can have multiple installations in one database if you give each
-
- * a unique prefix. Only numbers, letters, and underscores please!
-
- */
-
-$table_prefix = getenv_docker('WORDPRESS_TABLE_PREFIX', 'wp_');
-
-
-/**
-
- * For developers: WordPress debugging mode.
-
- *
-
- * Change this to true to enable the display of notices during development.
-
- * It is strongly recommended that plugin and theme developers use WP_DEBUG
-
- * in their development environments.
-
- *
-
- * For information on other constants that can be used for debugging,
-
- * visit the documentation.
-
- *
-
- * @link https://wordpress.org/support/article/debugging-in-wordpress/
-
- */
-
-define( 'WP_PHP_BINARY', 'php' );
-define( 'WP_TESTS_EMAIL', 'admin@example.org' );
-define( 'WP_TESTS_TITLE', 'Test Blog' );
-define( 'WP_SITEURL', 'http://localhost:8889/' );
-define( 'WP_HOME', 'http://localhost:8889/' );
-define( 'WP_DEBUG', true );
-
-
-// If we're behind a proxy server and using HTTPS, we need to alert WordPress of that fact
-
-// see also http://codex.wordpress.org/Administration_Over_SSL#Using_a_Reverse_Proxy
-
-if (isset($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] === 'https') {
-
-	$_SERVER['HTTPS'] = 'on';
-
-}
-
-// (we include this by default because reverse proxying is extremely common in container environments)
-
-
-if ($configExtra = getenv_docker('WORDPRESS_CONFIG_EXTRA', '')) {
-
-	eval($configExtra);
-
-}
-
-
-define( 'PHP_INI_MEMORY_LIMIT', '512M' );
-define( 'WP_MEMORY_LIMIT', '512M' );
-define( 'WP_DEBUG_LOG', true );
-define( 'WP_DEBUG_DISPLAY', true );
-define( 'SCRIPT_DEBUG', true );
-define( 'SMTP_HOST', 'mailhog' );
-define( 'SMTP_PORT', 1025 );
-define( 'WP_TESTS_DOMAIN', 'http://localhost:8889/' );
-/* That's all, stop editing! Happy publishing. */
-
-
-/** Absolute path to the WordPress directory. */
-
-if ( ! defined( 'ABSPATH' ) ) {
-
-	define( 'ABSPATH', __DIR__ . '/' );
-
-}
-
-
-/** Sets up WordPress vars and included files. */
-
-require_once ABSPATH . 'wp-settings.php';
-
diff --git a/tools/local-env/mu-plugins/phpmailer-mailhog.php b/tools/local-env/wp-content/mu-plugins/phpmailer-mailhog.php
similarity index 100%
rename from tools/local-env/mu-plugins/phpmailer-mailhog.php
rename to tools/local-env/wp-content/mu-plugins/phpmailer-mailhog.php