mev-beta/logs/ERROR_ANALYSIS_20251109.md

# MEV Bot Error & Inconsistency Analysis
**Date**: November 9, 2025
**Analysis Time**: 04:31 UTC
**Container**: mev-bot-production
**Total Log Lines Analyzed**: 15,769+

---

## 🚨 CRITICAL ISSUES FOUND

### 1. ❌ CRITICAL: Arbitrum Monitor Connection Failure

**Error:**
```
[ERROR] ❌ CRITICAL: Failed to create Arbitrum monitor:
failed to create contract executor:
failed to connect to Ethereum node:
websocket: bad handshake (HTTP status 403 Forbidden)
```

**Impact**: SEVERE - Bot is NOT using proper Arbitrum sequencer reader

**Details:**
- The bot attempted to connect to: `wss://arbitrum-mainnet.core.chainstack.com/53c30e7a941160679fdcc396c894fc57`
- Connection was rejected with HTTP 403 Forbidden
- This prevents the bot from using the proper ArbitrumMonitor with L2Parser

**Current Status:**
```
[ERROR] ❌ FALLBACK: Using basic block polling instead of proper sequencer reader
[INFO] ⚠️  USING FALLBACK BLOCK POLLING - This is NOT the proper sequencer reader!
[INFO] ⚠️  This fallback method has limited transaction analysis capabilities
[INFO] ⚠️  For full MEV detection, the proper ArbitrumMonitor with L2Parser should be used
```

**Consequences:**
- Limited transaction analysis capabilities
- May miss MEV opportunities that require L2-specific analysis
- Cannot detect certain types of arbitrage opportunities
- Reduced effectiveness compared to proper sequencer monitoring

**Root Cause:**
- Configuration mismatch between config.dev.yaml and .env
- config.dev.yaml specifies HTTP endpoint: `https://arb1.arbitrum.io/rpc`
- .env overrides with WSS endpoint that returns 403 Forbidden
- The WSS endpoint may require authentication or have access restrictions

**Recommended Fix:**
1. Use HTTP endpoint for contract executor: `https://arb1.arbitrum.io/rpc`
2. Or obtain proper credentials for the Chainstack WSS endpoint
3. Update configuration to use compatible RPC providers

---

### 2. 🐛 BUG: Multi-Hop Arbitrage Always Uses Amount 0

**Error Pattern:**
```
[DEBUG] Processing swap event: amount0=-7196652813349979, amount1=24235863
[DEBUG] Starting multi-hop arbitrage scan for token [...] with amount 0
```

**Occurrences**: 803 instances (ALL multi-hop scans)

**Impact**: SEVERE - Arbitrage detection is broken

**Details:**
Every time a swap event is detected with actual non-zero amounts, the subsequent multi-hop arbitrage scan is initiated with `amount 0`.

**Examples:**
| Swap Event Amount0 | Swap Event Amount1 | Multi-hop Scan Amount | Result |
|-------------------|-------------------|---------------------|--------|
| -7196652813349979 | 24235863 | **0** | ❌ Wrong |
| -184770257309794794 | 622210434 | **0** | ❌ Wrong |
| 189409592403453152 | -637446655 | **0** | ❌ Wrong |
| 356600000000000000 | -1199728957 | **0** | ❌ Wrong |
| 148930729359897857580 | -42645234 | **0** | ❌ Wrong |

**Expected Behavior:**
The multi-hop arbitrage scan should use the actual swap amount (either amount0 or amount1 depending on direction) to calculate realistic arbitrage opportunities.

**Actual Behavior:**
All scans use amount 0, which means:
- No realistic price impact calculations
- Cannot determine actual profitability
- Arbitrage detection will never find opportunities (amount 0 = no trade possible)

**Code Issue Location:**
The swap event processing code is not correctly passing the swap amount to the multi-hop arbitrage scanner. It's likely defaulting to 0 or using the wrong variable.

**Why This Matters:**
- **This is why Detected = 0** - The bot cannot find arbitrage opportunities with zero input amount
- Even if price discrepancies exist, they won't be detected because the calculation starts with 0

**Recommended Fix:**
```go
// Current (broken):
scanner.StartMultiHopScan(token, 0)

// Should be:
scanner.StartMultiHopScan(token, actualSwapAmount)
```

---

### 3. ⚠️ Configuration Inconsistency

**Issue**: Config file vs Environment variable mismatch

**Config.dev.yaml:**
```yaml
arbitrum:
  rpc_endpoint: "https://arb1.arbitrum.io/rpc"
  ws_endpoint: ""
```

**Environment (.env):**
```bash
ARBITRUM_RPC_ENDPOINT=wss://arbitrum-mainnet.core.chainstack.com/...
ARBITRUM_WS_ENDPOINT=wss://arbitrum-mainnet.core.chainstack.com/...
```

**Impact**: MEDIUM - Causes confusion and connection failures

**Details:**
- Environment variables override config file
- Config specifies HTTP endpoint (working)
- .env specifies WSS endpoint (403 Forbidden)
- This inconsistency led to the Critical Issue #1

**Recommended Fix:**
Align configuration sources to use the same, working endpoint.

---

## 📊 ERROR FREQUENCY ANALYSIS

### Errors by Type

| Error Type | Count | Severity | Status |
|-----------|-------|----------|--------|
| "arbitrage service disabled" | 96 | Low | ✅ Resolved (startup only) |
| WebSocket 403 Forbidden | 1 | **CRITICAL** | ❌ Active |
| Multi-hop amount=0 bug | 803 | **CRITICAL** | ❌ Active |
| Missing pools.json | ~50 | Low | ⚠️ Expected |
| Dashboard server closed | 1 | Low | ✅ Normal shutdown |
| Metrics server closed | 1 | Low | ✅ Normal shutdown |

### Critical Errors Timeline

**03:32:56 UTC** - Bot starts, connection to Arbitrum monitor fails
**03:32:56 UTC** - Falls back to basic block polling
**03:33:01 UTC** - First multi-hop scan with amount 0 (bug begins)
**04:31:00 UTC** - Still running in fallback mode (ongoing)

---

## 🔍 INCONSISTENCIES DETECTED

### 1. Swap Detection vs Arbitrage Analysis Mismatch

**Inconsistency:**
- **Swap Events Detected**: 600+ with valid non-zero amounts
- **Arbitrage Opportunities**: 0 detected
- **Multi-hop Scans**: 803 initiated, ALL with amount 0

**Analysis:**
The disconnect between detecting real swaps (with real amounts) and analyzing them for arbitrage (with zero amounts) explains why no opportunities are found.

**Expected Flow:**
```
Swap Event → Extract Amount → Analyze with Amount → Find Arbitrage
```

**Actual Flow:**
```
Swap Event → Extract Amount → Analyze with ZERO → Find Nothing ❌
```

### 2. Connection Success vs Monitor Failure

**Inconsistency:**
```
✅ RPC endpoints validated
❌ Failed to create Arbitrum monitor
```

**Analysis:**
- RPC validation passes (basic connectivity check)
- Arbitrum monitor creation fails (advanced sequencer connection)
- This suggests the endpoint works for basic queries but not for WebSocket subscriptions

### 3. Health Score vs Actual Functionality

**Inconsistency:**
- **Health Score**: 1/1 (Perfect)
- **Actual Status**: Running in fallback mode with broken arbitrage

**Analysis:**
The health check system is not detecting:
- Fallback mode operation
- Zero-amount arbitrage bug
- Missing Arbitrum monitor

**Recommendation:**
Enhance health checks to detect:
- Whether proper sequencer reader is active
- Whether arbitrage scans are using valid amounts
- Whether connection is in fallback mode

---

## 🔧 DETAILED ERROR ANALYSIS

### WebSocket Connection Failure Deep Dive

**Attempted Connection:**
```
wss://arbitrum-mainnet.core.chainstack.com/53c30e7a941160679fdcc396c894fc57
```

**Response:** `HTTP 403 Forbidden`

**Possible Causes:**
1. **API Key Restriction**: The endpoint may require additional authentication
2. **Rate Limiting**: Request may have been rate-limited
3. **Geographic Restriction**: IP address may be blocked
4. **Incorrect Protocol**: Endpoint may not support WSS connections
5. **Service Limitation**: Free tier may not support WebSocket subscriptions

**Evidence:**
- HTTP endpoint (https://) works for basic queries
- WSS endpoint (wss://) returns 403 Forbidden
- This pattern suggests WebSocket access is restricted

**Testing:**
```bash
# Test HTTP endpoint (likely works):
curl https://arbitrum-mainnet.core.chainstack.com/53c30e7a941160679fdcc396c894fc57

# Test WSS endpoint (returns 403):
wscat -c wss://arbitrum-mainnet.core.chainstack.com/53c30e7a941160679fdcc396c894fc57
```

---

## 📈 IMPACT ASSESSMENT

### Impact on MEV Detection

| Component | Expected | Actual | Impact |
|-----------|----------|--------|--------|
| Block Processing | ✅ Real-time | ✅ Real-time | None |
| Swap Detection | ✅ Accurate | ✅ Accurate | None |
| Arbitrage Analysis | ✅ With amounts | ❌ With zero | **SEVERE** |
| Opportunity Detection | ✅ Find MEV | ❌ Find nothing | **SEVERE** |
| Sequencer Monitoring | ✅ L2Parser | ❌ Fallback | **HIGH** |

### Performance Impact

- **CPU Usage**: 0.62% (efficient despite issues)
- **Memory Usage**: 0.8% (no leaks)
- **Scan Performance**: 35.48ms average (good)
- **Detection Rate**: 0% opportunities (broken)

### Data Accuracy Impact

| Metric | Status | Accuracy |
|--------|--------|----------|
| Blocks Processed | ✅ Accurate | 100% |
| Swap Events | ✅ Accurate | 100% |
| Swap Amounts | ✅ Accurate | 100% |
| Arbitrage Input | ❌ Wrong | 0% (all zeros) |
| Opportunities | ❌ Broken | 0% |

---

## 🎯 ROOT CAUSE ANALYSIS

### Root Cause #1: Configuration Error

**What Happened:**
1. Production deployment used .env file with WSS endpoint
2. WSS endpoint returns 403 Forbidden
3. Arbitrum monitor fails to initialize
4. Bot falls back to basic polling

**Why It Happened:**
- Environment variables override config file
- No validation that WSS endpoint is accessible
- No fallback RPC endpoint configured

**How to Prevent:**
- Validate all RPC endpoints during startup
- Test WebSocket connectivity before using
- Fail fast with clear error messages

### Root Cause #2: Logic Bug in Arbitrage Scanner

**What Happened:**
1. Swap event detected with actual amounts
2. Swap amounts extracted correctly
3. Multi-hop scanner called with hardcoded 0
4. No opportunities found (can't arbitrage with 0)

**Why It Happened:**
- Code bug: Wrong variable passed to scanner
- Missing tests for swap event → arbitrage flow
- No validation that scan amount > 0

**How to Prevent:**
- Add unit tests for swap processing
- Add assertion: amount > 0 before scanning
- Add integration tests for full flow

---

## 🚀 RECOMMENDED FIXES (Priority Order)

### PRIORITY 1: Fix Multi-Hop Amount Bug

**Severity**: CRITICAL
**Impact**: Enables arbitrage detection

**Fix:**
Locate swap event processing code and ensure actual swap amounts are passed to multi-hop scanner.

**File**: Likely `pkg/scanner/` or `pkg/arbitrage/`
**Search for**: `StartMultiHopScan` or `multi-hop arbitrage scan`
**Change**: Pass actual swap amount instead of 0

**Validation:**
```
Before: "Starting multi-hop arbitrage scan for token X with amount 0"
After: "Starting multi-hop arbitrage scan for token X with amount 356600000000000000"
```

### PRIORITY 2: Fix RPC Endpoint Connection

**Severity**: CRITICAL
**Impact**: Enables proper Arbitrum sequencer monitoring

**Fix Options:**

**Option A: Use HTTP Endpoint**
```bash
# Update .env:
ARBITRUM_RPC_ENDPOINT=https://arb1.arbitrum.io/rpc
ARBITRUM_WS_ENDPOINT=  # Leave empty or remove
```

**Option B: Fix WSS Endpoint**
1. Contact Chainstack support
2. Verify API key has WebSocket permissions
3. Check account tier limitations
4. Test endpoint accessibility

**Option C: Use Alternative Provider**
```bash
# Free public endpoints:
ARBITRUM_RPC_ENDPOINT=https://arbitrum-one.publicnode.com
ARBITRUM_WS_ENDPOINT=wss://arbitrum-one.publicnode.com
```

### PRIORITY 3: Add Validation & Health Checks

**Severity**: MEDIUM
**Impact**: Prevents future issues

**Add Checks:**
1. Validate RPC endpoint accessibility on startup
2. Verify arbitrage scan amounts are non-zero
3. Detect fallback mode in health checks
4. Alert when running without proper monitor

---

## 📝 SUMMARY

### Critical Issues (Must Fix):
1. ❌ **Multi-hop arbitrage always uses amount 0** (803 occurrences)
2. ❌ **Arbitrum monitor connection fails** (403 Forbidden)
3. ❌ **Running in fallback mode** (limited capabilities)

### Impact:
- **Current Detection Rate**: 0% (broken)
- **Expected Detection Rate**: Should be > 0% with proper configuration
- **Performance**: Good (35ms scans)
- **Stability**: Excellent (no crashes)

### Status:
✅ Bot is stable and running
✅ Data collection is accurate
❌ Arbitrage detection is broken
❌ Not using proper Arbitrum monitoring

### Next Steps:
1. Fix multi-hop amount bug (code change required)
2. Fix RPC endpoint configuration (config change)
3. Restart bot and verify "with amount [non-zero]" in logs
4. Monitor for successful arbitrage detection

---

*Report generated from comprehensive log analysis*
*Analysis covered 15,769+ log lines over 1 hour runtime*
*Issues identified: 2 critical, 1 medium, 3 low*