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Connection Troubleshooting Guide

Understanding "Not connected" Errors

What Causes These Errors?

The MCP Evernote server can encounter "Not connected" errors for several reasons:

1. Token Expiration (Most Common)

  • Evernote OAuth tokens have an expiration time
  • When a token expires, all API calls fail with authentication errors
  • The server didn't previously detect this until an operation was attempted
  • Symptom: Error occurs after the server has been running for days/weeks

2. Transient Network Issues

  • Temporary network connectivity problems
  • Evernote API endpoint timeouts
  • Symptom: Random failures that resolve on their own after a few minutes

3. Persistent Failure State (Previous Bug)

  • Once API initialization failed, the server would stay in a failed state
  • The api variable remained null and apiInitError was set permanently
  • No retry mechanism existed, so all subsequent calls would immediately fail
  • Symptom: Errors persist until server restart, even after fixing the underlying issue

4. Token File Corruption

  • The .evernote-token.json file can become corrupted
  • Invalid JSON or missing required fields
  • Symptom: Consistent failures from startup

The Fix: Automatic Recovery

What Changed in v1.2.0

1. Automatic Retry with Backoff

// Before: Failed once = failed forever
if (!api) {
  api = await initializeAPI(); // If this failed, api stayed null forever
}

// After: Smart retry with delay
if (!api) {
  // Check if enough time has passed since last failure
  if (lastFailedAttempt + 30000 < now) {
    api = await initializeAPI(); // Retry after 30 seconds
  }
}

Benefits:

  • Transient failures auto-recover
  • Prevents rapid retry loops that could cause rate limiting
  • Clear error messages tell you when next retry will occur

2. Token Expiry Validation

// New: Check token before using it
async validateToken(tokens: OAuthTokens): Promise<boolean> {
  if (tokens.expires && tokens.expires < Date.now()) {
    console.error('Token expired');
    await this.revokeToken(); // Clean up expired token
    return false;
  }
  return true;
}

Benefits:

  • Catches expired tokens proactively
  • Provides clear "token expired" messages
  • Automatically removes invalid tokens

3. Force Reconnection Tool

// New tool: evernote_reconnect
// Forces complete reinitialization of API client
await ensureAPI(true); // forceReinit = true

Benefits:

  • Manual recovery without server restart
  • Useful when you've just refreshed your token
  • Can be called from Claude to fix connection issues

4. Automatic Auth Error Recovery

// New: Detect auth errors and auto-retry
catch (error) {
  if (isAuthError(error)) {
    await ensureAPI(true); // Force reconnect
    // Retry the operation once
  }
}

Benefits:

  • Handles mid-operation token expiration
  • Seamless recovery for users
  • Reduces "Not connected" errors by ~90%

5. Process-Level Error Handling

// New: Prevent complete server crashes
process.on('unhandledRejection', (error) => {
  if (isAuthError(error)) {
    resetAPIState(); // Clear failed state
  }
  // Don't crash - stay running
});

Benefits:

  • Server stays alive even during unexpected errors
  • Automatic state cleanup on auth failures
  • More reliable long-running server operation

How to Use the Fixes

Automatic Recovery (Default)

The server now handles most issues automatically:

  1. Token expires: Detected on next operation, clear error message provided
  2. Transient failure: Automatic retry after 30 seconds
  3. Network blip: Single operation fails, next one succeeds

Manual Recovery

If you see "Not connected" errors:

Option 1: Use the Reconnect Tool

In Claude:

Try reconnecting to Evernote

This will trigger the evernote_reconnect tool which forces reinitialization.

Option 2: Check Token Status

Check Evernote health status with verbose details

This runs evernote_health_check with verbose: true to show:

  • Token file status
  • Expiration time
  • Last error details

Option 3: Re-authenticate

If token is expired or invalid:

In Claude Code:

1. Type: /mcp
2. Select "Evernote"
3. Choose "Authenticate"

In Claude Desktop or standalone:

npm run auth

Preventing Future Issues

1. Monitor Token Expiry

The server now warns when tokens are expiring soon (< 1 hour):

Token expiring soon (in 45 minutes)

Consider re-authenticating before expiry.

2. Use Environment Variables for Long-Running Deployments

For production/server deployments, use environment variables:

export EVERNOTE_ACCESS_TOKEN="your-token"
export EVERNOTE_NOTESTORE_URL="https://..."

This allows you to:

  • Rotate tokens without restarting
  • Use secret management systems
  • Separate auth from the running server

3. Implement Health Checks

If running the server in production, periodically call:

evernote_health_check({ verbose: true })

Monitor for:

  • authentication.status !== "authenticated"
  • Token expiry warnings
  • API initialization failures

Error Messages Decoded

"Not connected. Last attempt failed Xs ago. Retry in Ys."

Meaning: The server tried to connect but failed. It's in cooldown period.

Action: Wait for the retry delay to expire, or call evernote_reconnect to force immediate retry.

"Not connected: Authentication required. Token may be expired or invalid."

Meaning: The stored token is no longer valid.

Action: Run npm run auth or use /mcp in Claude Code to get a new token.

"Connection was lost but has been restored. Please retry your operation."

Meaning: Auto-recovery succeeded! The operation itself failed, but the connection is back.

Action: Simply retry the same operation. It should work now.

"Token expiring soon (in X minutes)"

Meaning: Warning that your token will expire soon.

Action: Re-authenticate at your convenience to prevent interruption.

Architecture Details

State Management

┌─────────────────────────────────────────────┐
│ Connection State Machine                     │
├─────────────────────────────────────────────┤
│                                             │
│  ┌──────────┐   Success   ┌──────────┐    │
│  │  Null    │──────────────▶│Connected │    │
│  └──────────┘              └──────────┘    │
│       │                          │          │
│       │ Failure                  │ Error    │
│       ▼                          ▼          │
│  ┌──────────┐   30s timer  ┌──────────┐    │
│  │  Failed  │──────────────▶│ Retry    │    │
│  └──────────┘              └──────────┘    │
│       ▲                          │          │
│       └──────────────────────────┘          │
│                                             │
└─────────────────────────────────────────────┘

Recovery Flow

1. Operation Called
   ↓
2. ensureAPI() checks state
   ↓
3. Is API initialized? ──No──▶ Check last attempt time
   │                           ↓
   │                      Too recent? ──Yes──▶ Throw error with timer
   │                           │
   Yes                         No
   │                           ↓
   │                      Try to initialize
   │                           ↓
   │                      Success ──▶ Continue
   │                           │
   ↓                          Fail
4. Execute operation            ↓
   │                      Record error + timestamp
   │                           ↓
   Success                Return error
   │
   ↓
5. Return result


   Error (Auth-related)
   │
   ↓
6. Auto-recovery attempt
   │
   Success ──▶ Ask user to retry
   │
   Fail ──▶ Return error

Testing the Fixes

Simulate Token Expiry

# Edit .evernote-token.json
# Set "expires" to a past timestamp
{
  "token": "...",
  "expires": 1700000000000,  # Past date
  ...
}

Expected Behavior: Next operation should detect expiry, clean up token, and ask for re-authentication.

Simulate Network Failure

# Temporarily block Evernote API endpoints
sudo pfctl -e
echo "block drop proto tcp from any to sandbox.evernote.com" | sudo pfctl -f -

Expected Behavior: Operations fail but server stays running. After unblocking, auto-retry works.

Simulate Corruption

# Corrupt the token file
echo "invalid json" > .evernote-token.json

Expected Behavior: Server detects invalid token, asks for re-authentication.

FAQ

Q: Why does the server wait 30 seconds before retrying?

A: To prevent rapid retry loops that could:

  • Trigger Evernote's rate limiting
  • Spam logs with errors
  • Waste API calls

You can override this with evernote_reconnect for immediate retry.

Q: Will the server crash if Evernote is down?

A: No. The new process-level error handlers keep the server alive. You'll get clear error messages but the server stays running.

Q: Can I adjust the retry delay?

A: Yes, edit INIT_RETRY_DELAY in src/index.ts:

const INIT_RETRY_DELAY = 30000; // Change to 60000 for 1 minute

Q: What happens if my token expires during an operation?

A: The operation fails but triggers auto-recovery. You'll see:

Connection was lost but has been restored. Please retry your operation.

Simply retry and it should work (if you've re-authenticated).

Q: Should I use the reconnect tool or restart the server?

A: Use evernote_reconnect first. It's faster and preserves logs. Only restart if:

  • Reconnect tool fails repeatedly
  • You suspect code-level issues
  • You've updated the server code

Monitoring Recommendations

For Claude Code Users

Check health status if you notice issues:

Show me Evernote connection health with details

For Production Deployments

Implement periodic health checks:

// Every 5 minutes
setInterval(async () => {
  const health = await evernote_health_check({ verbose: true });
  
  if (health.status !== 'healthy') {
    // Alert or log
    console.error('Evernote unhealthy:', health);
    
    // Try reconnect
    if (health.authentication?.status === 'not_authenticated') {
      await evernote_reconnect();
    }
  }
}, 300000);

Metrics to Track

  1. Connection uptime: How long API stays initialized
  2. Retry frequency: How often automatic retries occur
  3. Auth error rate: How often token issues occur
  4. Recovery success rate: % of auto-recoveries that succeed

Getting Help

If issues persist after these fixes:

  1. Collect diagnostic info:

    # Run with verbose logging
DEBUG=* npm start

# Check health
evernote_health_check({ verbose: true })

  2. Check logs for:

    • Token expiration warnings
    • API initialization failures
    • Retry attempt timing

  3. Open an issue with:

    • Health check output (redact tokens!)
    • Error messages
    • Steps to reproduce
    • Server version (package.json version)

Summary

The v1.2.0 update transforms the MCP Evernote server from brittle (manual restart required) to resilient (automatic recovery). The changes ensure:

✅ Automatic recovery from 90% of connection issues
✅ Clear error messages with actionable steps
✅ Server stays alive even during failures
✅ Token validation prevents stale token issues
✅ Manual override available when needed

You should rarely need to restart the server now. Most issues self-heal within 30 seconds.