diff --git a/README.md b/README.md
index 13cf8c0..78afd70 100644
--- a/README.md
+++ b/README.md
@@ -85,7 +85,7 @@ The default deploy flow is:
 
 ```sh
 git pull --ff-only
-npm install --include=dev
+npm install --production=false --include=dev --omit=optional
 npm run build
 pm2 reload tssbot-web --update-env
 ```
@@ -94,6 +94,13 @@ Only processes listed in `PM2_RESTART_TARGETS` are reloaded. The default is
 `tssbot-web`, so unrelated PM2 processes are left alone. The webhook exits after
 24 hours so PM2 restarts it cleanly.
 
+When webhook code changes are deployed, restart the webhook process once so PM2
+loads the updated listener:
+
+```sh
+pm2 reload tssbot-webhook --update-env
+```
+
 The webhook listener reads `.env` on startup. To send a Discord notification
 whenever the listener starts or restarts, set:
 
diff --git a/webhook.cjs b/webhook.cjs
index cb93a97..525f2a7 100644
--- a/webhook.cjs
+++ b/webhook.cjs
@@ -97,6 +97,23 @@ function run(command, args, options = {}) {
   })
 }
 
+async function ensureBuildDependencies() {
+  await run('npm', ['install', '--production=false', '--include=dev', '--omit=optional'], {
+    env: {
+      NODE_ENV: 'development',
+      npm_config_include: 'dev',
+      npm_config_omit: 'optional',
+      npm_config_production: 'false',
+    },
+  })
+
+  try {
+    require.resolve('@vitejs/plugin-react')
+  } catch {
+    throw new Error('@vitejs/plugin-react is missing after npm install; dev dependencies were not installed')
+  }
+}
+
 function postDiscordWebhook(payload) {
   if (!DISCORD_WEBHOOK_URL) return Promise.resolve()
 
@@ -162,11 +179,7 @@ function notifyDiscordRestart() {
 
 async function deploy() {
   await run('git', ['pull', '--ff-only'])
-  await run('npm', ['install', '--include=dev'], {
-    env: {
-      npm_config_production: 'false',
-    },
-  })
+  await ensureBuildDependencies()
   await run('npm', ['run', 'build'])
 
   for (const target of RESTART_TARGETS) {