/dev-server

Start the dev server for the current project and keep it running.

All commands run in the current working directory — never hardcode or cd to a specific project path.

Arguments

Port number: $ARGUMENTS

If $ARGUMENTS is empty or not a number, determine the port by checking the project's config files (e.g., vite.config.ts, app.config.ts, .env, package.json scripts) for a configured dev server port.

Important: Always use the determined port. If the port is occupied, kill the existing process — never switch to a different port. The user expects the server at a consistent URL.

Instructions

Discover how to start the dev server

Look at the project's justfile, package.json scripts, Makefile, or similar to find the dev server command. Common patterns:

• just dev
• pnpm dev / npm run dev
• make dev

If the project has dependencies that need building first (e.g., a monorepo shared package), identify and run those build steps before starting the server.

Kill anything on the port

Check if the port is already in use. If so, kill the process occupying it:

lsof -ti :<port> | xargs kill -9 2>/dev/null || true

Run any prerequisite builds

If the project requires building shared/dependency packages first, do so now.

Start the dev server in the background

Run the discovered dev command with PORT=<port> (if the project uses a PORT env var), using run_in_background.

Wait for the server to be ready

Poll until the server responds:

for i in $(seq 1 30); do curl -sf http://localhost:<port>/ > /dev/null 2>&1 && echo "ready" && break; sleep 1; done

Report the URL

Tell the user the dev server is running at http://localhost:<port>/.

Start a watchdog loop

Use /loop 1m to run a recurring check every 1 minute. The check should:

• Verify the server is responding: curl -sf http://localhost:<port>/ > /dev/null 2>&1
• If it's not responding:
  • Kill anything on the port: lsof -ti :<port> | xargs kill -9 2>/dev/null || true
  • Re-run prerequisite builds if applicable
  • Restart the dev server (in background)
  • Notify the user that the server was restarted