workmux setup

.workmux.yaml

@@ -29,7 +29,7 @@ post_create:
 panes:
   - command: <agent>
     focus: true
-  - command: "[ -f .env.local ] && source .env.local; cd backend && PORT=${BACKEND_PORT:-8000} cargo run"
+  - command: "[ -f .env.local ] && source .env.local; cd backend && PORT=${BACKEND_PORT:-8000} cargo watch -x run"
     split: horizontal
   - command: "[ -f .env.local ] && source .env.local; cd frontend && REMOTE=${REMOTE:-http://localhost:${BACKEND_PORT:-8000}} npm run dev -- --port ${FRONTEND_PORT:-3000}"
     split: vertical

README_WORKMUX_DEV.md

@@ -0,0 +1,141 @@
+# Windmill Development with workmux
+
+This guide covers the workmux-based development setup for Windmill. Each worktree gets its own tmux window with a Claude Code agent, a backend server (with auto-reload), and a frontend dev server — all on isolated ports.
+
+## Prerequisites
+
+- tmux
+- Rust toolchain (rustup)
+- Node.js + npm
+- PostgreSQL running locally (see `backend/.env`)
+
+## Installation
+
+### 1. Install workmux
+
+```bash
+cargo install workmux
+```
+
+### 2. Install the Claude Code plugin
+
+```bash
+workmux claude install
+```
+
+This lets workmux manage Claude Code agents in worktree panes.
+
+### 3. Install cargo-watch
+
+Used for auto-recompiling the backend on file changes:
+
+```bash
+cargo install cargo-watch
+```
+
+## Port Slot System
+
+Each worktree is assigned a **slot** that determines its ports:
+
+| Slot | Backend | Frontend |
+|------|---------|----------|
+| 0    | 8000    | 3000     |
+| 1    | 8010    | 3010     |
+| 2    | 8020    | 3020     |
+| 3    | 8030    | 3030     |
+| ...  | ...     | ...      |
+
+- **Slot 0** is reserved for the main worktree (default `cargo run` / `npm run dev`).
+- Without `WM_SLOT`, the script auto-assigns the first available slot (starting from 1) and prints it.
+- With `WM_SLOT=N`, it uses that slot and errors if the ports are taken.
+
+## SSH Port Forwarding
+
+If you develop over SSH, add this to `~/.ssh/config` on your **local machine** to pre-configure tunnels for each slot:
+
+```
+Host windmill-dev
+  HostName <remote-ip>
+  User <username>
+  # Slot 0 (main worktree)
+  LocalForward 8000 localhost:8000
+  LocalForward 3000 localhost:3000
+  # Slot 1
+  LocalForward 8010 localhost:8010
+  LocalForward 3010 localhost:3010
+  # Slot 2
+  LocalForward 8020 localhost:8020
+  LocalForward 3020 localhost:3020
+  # Slot 3
+  LocalForward 8030 localhost:8030
+  LocalForward 3030 localhost:3030
+```
+
+Then connect once and all tunnels are active:
+
+```bash
+ssh windmill-dev
+```
+
+Access the frontend at `http://localhost:<frontend-port>` in your local browser.
+
+## Quickstart
+
+```bash
+# Create a new worktree (auto-assigns slot, prints ports)
+workmux add my-feature
+
+# Or with an explicit slot
+WM_SLOT=2 workmux add my-feature
+```
+
+This will:
+
+1. Create a git worktree + branch `my-feature`
+2. Run `scripts/worktree-env` to assign ports and write `.env.local`
+3. Open a tmux window with three panes:
+   - **Claude Code agent** (focused)
+   - **Backend**: `cargo watch -x run` on the assigned port (auto-reloads on save)
+   - **Frontend**: `npm run dev` proxying to the backend
+
+Check which ports were assigned:
+
+```bash
+cat <worktree-path>/.env.local
+```
+
+### Sending work to the agent
+
+```bash
+# Send a prompt to the agent in a worktree
+workmux send my-feature "fix the login bug in auth.rs"
+
+# Check agent status
+workmux status
+```
+
+### Cleaning up
+
+```bash
+# Close the tmux window but keep the worktree
+workmux close my-feature
+
+# Remove everything (worktree, branch, tmux window)
+workmux rm my-feature
+
+# Merge into main, then clean up
+workmux merge my-feature
+```
+
+## Configuration
+
+The setup is defined in `.workmux.yaml` at the repo root. Key sections:
+
+- **`post_create`**: Runs `scripts/worktree-env` to generate `.env.local` with port assignments
+- **`panes`**: Defines the tmux layout (agent, backend, frontend)
+- **`files.copy`**: Copies `backend/.env` and `scripts/` into each worktree
+- **`files.symlink`**: Symlinks `node_modules` and `.svelte-kit` to avoid reinstalling per worktree
+
+## Login
+
+Default credentials: `admin@windmill.dev` / `changeme`

scripts/worktree-env

@@ -13,13 +13,33 @@ find_port() {
   echo "$port"
 }
 
-# Hash the handle to get a deterministic port offset (0-99)
-hash=$(echo -n "$WM_HANDLE" | md5sum | cut -c1-4)
-offset=$((16#$hash % 100))
+if [[ -z "${WM_SLOT:-}" ]]; then
+  # Auto-assign: find the first slot (1-99) where both ports are free
+  # Slot 0 (8000/3000) is reserved for the main worktree
+  for slot in $(seq 1 99); do
+    bp=$((8000 + slot * 10))
+    fp=$((3000 + slot * 10))
+    if ! port_in_use "$bp" && ! port_in_use "$fp"; then
+      WM_SLOT=$slot
+      break
+    fi
+  done
+  if [[ -z "${WM_SLOT:-}" ]]; then
+    echo "ERROR: No available slot found (tried 1-99)" >&2
+    exit 1
+  fi
+  echo "Auto-assigned slot $WM_SLOT"
+fi
 
-# Find available ports starting from the hash-based offset
-backend_port=$(find_port $((8000 + offset * 10)))
-frontend_port=$(find_port $((3000 + offset * 10)))
+# Slot-based: predictable ports for SSH forwarding
+# Slot 0 = 8000/3000, slot 1 = 8010/3010, slot 2 = 8020/3020, etc.
+backend_port=$((8000 + WM_SLOT * 10))
+frontend_port=$((3000 + WM_SLOT * 10))
+
+if port_in_use "$backend_port" || port_in_use "$frontend_port"; then
+  echo "ERROR: Slot $WM_SLOT ports ($backend_port/$frontend_port) already in use" >&2
+  exit 1
+fi
 
 # Generate .env.local with port overrides
 cat > .env.local <<EOF