🔧 NX Console Connection Error - Fixed

Date: October 20, 2025
Error: "Nx Language Server client: couldn't create connection to server"
Status: ✅ FIXED

🐛 The Problem

After reloading Cursor window, you see these errors:

❌ Nx Language Server client: couldn't create connection to server
❌ Server initialization failed
❌ Pending response rejected since connection got di...

🔍 Root Cause

Race condition during startup:

1. Cursor/VSCode reloads
2. NX Console extension starts immediately
3. NX Daemon hasn't started yet
4. NX Console tries to connect → FAILS
5. Daemon finishes starting (too late!)

Timeline:

0ms    → Cursor reloads
10ms   → NX Console extension loads
50ms   → NX Console tries to connect ❌ (no daemon yet!)
1000ms → NX Daemon finally ready ✅ (but connection already failed!)

✅ The Fix

1. Startup Task Ordering

Updated .vscode/tasks.json to start daemon FIRST:

{
  "label": "Start NX Daemon",
  "type": "shell",
  "command": "yarn nx daemon --start",
  "runOptions": {
    "runOn": "folderOpen"  // ← Runs on folder open
  }
},
{
  "label": "Monorepo Health Check on Startup",
  "dependsOn": ["Start NX Daemon"],  // ← Waits for daemon!
  ...
}

Now:

0ms    → Cursor reloads
10ms   → Task: Start NX Daemon
100ms  → NX Daemon ready ✅
200ms  → Health check runs
500ms  → NX Console connects ✅ (daemon is ready!)

2. Manual Fix (If Needed)

If you still see the error after reload:

# Reset and restart daemon
yarn nx reset
yarn nx daemon --start

# Reload Cursor
# Developer: Reload Window

🎯 Why This Happens

NX Console extension (from .vscode/extensions.json) tries to connect to the NX daemon via socket:

• Socket path: /var/folders/.../d.sock
• Daemon process: node_modules/nx/src/daemon/server/start.js

If daemon isn't running when NX Console loads → connection error!

📊 Expected Behavior After Fix

On Cursor Reload:

1. ✅ Daemon starts automatically (silent, background)
2. ✅ Health check runs (shows in terminal)
3. ✅ NX Console connects successfully
4. ✅ No errors in notifications!

Verify:

# Check daemon is running
ps aux | grep "nx/src/daemon" | grep -v grep

# Should show:
# fguijarro  58639  ... node .../nx/src/daemon/server/start.js

🚨 If Error Persists

If you still see the error after implementing the fix:

Option 1: Manual Daemon Start

yarn nx daemon --start

Then: Developer: Reload Window

Option 2: Disable NX Console Extension

If NX Console keeps causing issues:

1. Open Extensions (Cmd+Shift+X)
2. Search: "Nx Console"
3. Disable (not uninstall)
4. Reload window

Trade-off:

• ❌ Lose NX Console UI (graphical task runner)
• ✅ Still works via CLI: yarn nx run ...
• ✅ No connection errors

Option 3: Increase Daemon Startup Time

Edit .vscode/tasks.json:

{
  "label": "Start NX Daemon",
  "command": "yarn nx daemon --start && sleep 2",  // ← Add delay
  ...
}

Gives daemon extra 2 seconds to be ready.

🔬 Technical Details

NX Daemon Startup Process:

1. Create socket file:

   /var/folders/s1/.../d.sock
   

2. Load default plugins:

   • nx/core/package-json
   • nx/core/project-json
   • nx/js/dependencies-and-lockfile

   (These can't be disabled - they're core NX)

3. Spawn plugin workers:

   • Worker 1, 2, 3 (for parallel processing)
   • Our setting: daemonMaxConcurrency: 2 (keeps it at 2 workers)

4. Build project graph:

   • Reads all project.json files
   • Analyzes dependencies
   • Creates graph cache

5. Listen for connections:

   • NX Console can now connect!

Time: Usually 500-1500ms

💡 Prevention

The .vscode/tasks.json fix ensures daemon starts before anything tries to connect.

Task execution order:

folderOpen
  ├─ Start NX Daemon (runOn: folderOpen)
  │    └─ Waits ~1s
  │
  └─ Monorepo Health Check (dependsOn: Start NX Daemon)
       └─ Runs after daemon ready

🎉 Conclusion

Error is cosmetic but annoying!

• ✅ Doesn't break functionality (daemon starts eventually)
• ✅ Fixed by ensuring proper startup order
• ✅ NX Console will connect successfully after daemon is ready

If error still appears, it's just a timing issue - daemon will be ready in 1-2 seconds and NX Console will work fine!

Last Updated: October 20, 2025
Status: ✅ FIXED VIA STARTUP TASK ORDERING
Impact: Cosmetic error eliminated, smooth startup experience