Claude Flow Hook Customizing

📖 Overview

A Complete Guide to Verification Hooks with Claude Flow

This guide demonstrates how to use Claude Code's hook system to ensure AI agents create real, functional, and secure code - not mocks or simulations. The hooks provide both preventive guidance (before edits) and verification feedback (after edits) to maintain code quality.

Reference

REFERENCE.md

Examples

./examples/memory-workflow-mcp.js ./examples/session-memory-workflow.sh

🎯 The Problem

One of the hardest problems in fast-moving development is that things slip through the cracks:

• A console.log left behind
• A mock never removed
• An API still pointing at localhost
• Hardcoded secrets in production

By the time it hits production, you're firefighting instead of building.

✅ The Solution

Make verification automatic, not optional. That's where Claude Flow verification hooks come in.

This tutorial shows you how to wire up Claude Code PreToolUse and PostToolUse hooks that keep your coding agents on track using the Claude Flow Truth and Verification tools.

💡 Think of it as: Having a senior developer quietly checking over your shoulder every time you hit save, but without slowing you down.

🔍 What Claude Code Sees: Before & After Every Operation

Example: Creating a Production API Handler

❌ What Claude Attempts to Write (BAD):

// api/users.js
const API_KEY = "sk-prod-12345"; // Quick fix for now
const password = "admin123"; 

function getUserData() {
  // TODO: Implement real database call
  console.log("Mock response for testing");
  return { mock: true, data: "placeholder" };
}

fetch("http://api.example.com/users"); // Will fix SSL later

🛡️ What the Hooks Enforce BEFORE Creation:

🎯 PRE-EDIT VERIFICATION
Target: /api/users.js
⚠️  REQUIREMENTS:
  • Real implementations only (no mocks in production)
  • No hardcoded secrets - use environment variables
  • Complete error handling
  • Secure protocols (HTTPS)

🔍 Mandatory Verification Checklist:
  ✓ Implementation MUST be FULLY FUNCTIONAL
  ✓ NO mocks/stubs/simulations (unless test file)
  ✓ Real API connections (not placeholders)
  ✓ Actual data persistence (not in-memory only)
  ✓ Complete error handling (not just happy path)
  ✓ Production-ready code (not proof-of-concept)

🔐 Security Requirements:
  ⚠️ NEVER hardcode credentials or secrets
  ⚠️ Use environment variables for sensitive data
  ⚠️ No API keys, passwords, or tokens in code
  ⚠️ Validate and sanitize ALL user inputs
  ⚠️ Use secure connection protocols (HTTPS/TLS)
  ⚠️ Implement proper authentication & authorization

🚫 REJECT IF YOU SEE:
  • Hardcoded: API_KEY="sk-..."
  • Direct secrets: password="admin123"
  • TODO/FIXME without implementation
  • return mockData or simulatedResponse
  • console.log with sensitive data
  • Unvalidated user inputs (SQL injection risk)
  • HTTP instead of HTTPS for APIs

📊 What Gets Verified AFTER Creation:

✅ POST-EDIT ANALYSIS
Modified: /api/users.js
Checking for issues...
  ⚠️  TODO comments found
  ⚠️  console.log detected
  🚨 Hardcoded password!

📊 CODE QUALITY ANALYSIS
File: /api/users.js
  ❌ TODO found (-15)
  ⚠️  console.log (-5)
  ❌ Mock detected (-25)
  🚨 Hardcoded API key (-30)
  🚨 Hardcoded password (-30)
  ⚠️  Insecure HTTP protocol (-10)

📊 QUALITY SCORE: -15/100
🚫 BELOW THRESHOLD (95) - Review required!

🔧 REQUIRED ACTIONS:
  1. Fix all security issues immediately
  2. Replace mocks with real implementations
  3. Use environment variables for secrets
  4. Remove debug statements

🔬 CLAUDE FLOW VERIFICATION
Truth Score: 0.45
Status: ❌ FAILED - Below 0.95 threshold

✅ The Result: Claude Rewrites Properly

// api/users.js
const API_KEY = process.env.API_KEY;
const password = process.env.DB_PASSWORD;

async function getUserData() {
  try {
    const response = await fetch("https://api.example.com/users", {
      headers: { 'Authorization': `Bearer ${API_KEY}` }
    });
    if (!response.ok) throw new Error(`HTTP error! status: ${response.status}`);
    return await response.json();
  } catch (error) {
    logger.error('Failed to fetch user data:', error);
    throw new Error('Unable to retrieve user data');
  }
}

🎯 How Hooks Work

Claude Code's hook system fires at specific points:

🚀 Working Implementation (Tested & Confirmed)

Step 1: Create the Hook Analyzer Script

First, create a script to handle complex security checks without quote escaping issues:

# Create .claude/hook-analyzer-v2.sh
cat > .claude/hook-analyzer-v2.sh << 'EOF'
#!/bin/bash
# Enhanced hook analyzer with dynamic Claude Flow integration

FILE="$1"
echo "✅ POST-EDIT ANALYSIS" | tee -a /tmp/claude-hooks.log
echo "Modified: $FILE" | tee -a /tmp/claude-hooks.log
echo "Security Check Results:" | tee -a /tmp/claude-hooks.log

# Check for TODOs
if grep -q 'TODO' "$FILE" 2>/dev/null; then
  echo "  ⚠️  TODO found" | tee -a /tmp/claude-hooks.log
else
  echo "  ✓ No TODOs" | tee -a /tmp/claude-hooks.log
fi

# Check for console.log
if grep -q 'console.log' "$FILE" 2>/dev/null; then
  echo "  ⚠️  console.log found" | tee -a /tmp/claude-hooks.log
else
  echo "  ✓ No console.log" | tee -a /tmp/claude-hooks.log
fi

# Check for hardcoded secrets (improved regex)
if grep -qiE '(password|secret|token|key|credential)[[:space:]]*=[[:space:]]*["'"'"'][^"'"'"']+["'"'"']' "$FILE" 2>/dev/null; then
  echo "  🚨 Hardcoded secret detected!" | tee -a /tmp/claude-hooks.log
else
  echo "  ✓ No obvious secrets" | tee -a /tmp/claude-hooks.log
fi

# Dynamic Claude Flow verification
if command -v npx >/dev/null 2>&1; then
  echo "" | tee -a /tmp/claude-hooks.log
  echo "📊 Claude Flow Verification:" | tee -a /tmp/claude-hooks.log
  
  # Run verification and capture output
  VERIFY_OUTPUT=$(npx claude-flow@alpha verify verify "$FILE" --agent coder --threshold 0.95 2>&1)
  
  # Extract and display actual scores
  echo "$VERIFY_OUTPUT" | grep -E "Score:|compile:|test:|lint:|Status:" | while read line; do
    echo "   $line" | tee -a /tmp/claude-hooks.log
  done
  
  # Get current truth scores
  TRUTH_JSON=$(npx claude-flow@alpha truth --json 2>/dev/null)
  if [ $? -eq 0 ]; then
    AVG_SCORE=$(echo "$TRUTH_JSON" | jq -r '.averageScore // "N/A"')
    THRESHOLD=$(echo "$TRUTH_JSON" | jq -r '.threshold // "0.85"')
    echo "   Overall Average: $AVG_SCORE (threshold: $THRESHOLD)" | tee -a /tmp/claude-hooks.log
  fi
fi
EOF

# Make it executable
chmod +x .claude/hook-analyzer-v2.sh

Step 2: Configure .claude/settings.json

Add this configuration with automated feedback loop:

{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": "Write|Edit|MultiEdit",
        "hooks": [
          {
            "type": "command",
            "command": "echo '🎯 PRE-EDIT VERIFICATION' | tee -a /tmp/claude-hooks.log && FILE=$(cat | jq -r '.tool_input.file_path // .tool_input.path // empty') && echo \"Target: $FILE\" | tee -a /tmp/claude-hooks.log && echo '⚠️  REQUIREMENTS:' | tee -a /tmp/claude-hooks.log && echo '  • Real implementations only (no mocks in production)' | tee -a /tmp/claude-hooks.log && echo '  • No hardcoded secrets - use environment variables' | tee -a /tmp/claude-hooks.log && echo '  • Complete error handling' | tee -a /tmp/claude-hooks.log && echo '  • Secure protocols (HTTPS)' | tee -a /tmp/claude-hooks.log"
          }
        ]
      }
    ],
    "PostToolUse": [
      {
        "matcher": "Write|Edit|MultiEdit",
        "hooks": [
          {
            "type": "command",
            "command": "FILE=$(cat | jq -r '.tool_input.file_path // .tool_input.path // empty') && /workspaces/flow-nexus/.claude/hook-analyzer-v2.sh \"$FILE\""
          }
        ]
      },
      {
        "matcher": "Bash",
        "hooks": [
          {
            "type": "command",
            "command": "CMD=$(cat | jq -r '.tool_input.command // empty') && echo \"Command executed: $CMD\" | tee -a /tmp/claude-hooks.log"
          }
        ]
      }
    ],
    "UserPromptSubmit": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "if [ -f /tmp/claude-hooks.log ] && [ -s /tmp/claude-hooks.log ]; then echo '<user-prompt-submit-hook>'; echo '📋 Recent Hook Activity:'; tail -30 /tmp/claude-hooks.log; echo '</user-prompt-submit-hook>'; > /tmp/claude-hooks.log; fi"
          }
        ]
      }
    ]
  }
}

✨ Key Improvements in This Approach

1. 📝 Script-Based Analysis

• Problem Solved: Complex quote escaping issues in JSON
• Solution: Dedicated bash script for security analysis
• Benefit: Clean, maintainable code without syntax errors

2. 🔄 Automated Feedback Loop

• Feature: UserPromptSubmit hook with <user-prompt-submit-hook> tags
• How it Works: Automatically shares hook output with Claude
• Result: Real-time visibility into all verification checks

3. 📊 Dynamic Scoring

• Before: Static values like test: 0.60
• After: Real Claude Flow scores that reflect actual code quality
• Example: Overall Average: 0.9 (threshold: 0.85)

4. 💾 Persistent Logging

• Location: /tmp/claude-hooks.log
• Features: Append mode with tee -a for complete history
• Cleanup: Automatic reset after each UserPromptSubmit

5. 🔐 Enhanced Secret Detection

• Improved Regex: Case-insensitive pattern matching
• Detects Variables:
  • password, secret, token, key, credential
  • Any variation: apiKey, API_KEY, authToken, etc.
• Pattern: (password|secret|token|key|credential)[[:space:]]*=[[:space:]]*["'][^"']+["']

🔬 Advanced Configurations

Claude Flow Truth Verification

Integrate Claude Flow's verification system for automated truth scoring:

{
  "PreToolUse": [{
    "matcher": "Write|Edit|MultiEdit",
    "hooks": [{
      "type": "command",
      "command": "echo '🔬 Initializing Claude Flow Verification...' && npx claude-flow@alpha verify init strict 2>/dev/null && echo '✅ Strict mode: 0.95 threshold' || echo '⚠️  Claude Flow not available'"
    }]
  }],
  "PostToolUse": [{
    "matcher": "Write|Edit|MultiEdit",
    "hooks": [{
      "type": "command",
      "command": "FILE=$(cat | jq -r '.tool_input.file_path // .tool_input.path // empty') && echo '📊 CLAUDE FLOW VERIFICATION' && npx claude-flow@alpha verify verify \"$FILE\" --agent coder --threshold 0.95 2>/dev/null || echo '  Manual check required' && npx claude-flow@alpha truth --agent coder --json 2>/dev/null | jq -r '\"Truth Score: \\(.averageScore // \"N/A\")\"' || true"
    }]
  }]
}

Quantitative Scoring with Manual Fallback

Combine Claude Flow verification with manual scoring:

{
  "PostToolUse": [{
    "matcher": "Write|Edit|MultiEdit",
    "hooks": [{
      "type": "command",
      "command": "FILE=$(cat | jq -r '.tool_input.file_path // .tool_input.path // empty') && echo '📊 CODE QUALITY ANALYSIS' && echo \"File: $FILE\" && SCORE=100 && grep -q 'TODO' \"$FILE\" 2>/dev/null && { echo '  ❌ TODO found (-15)'; SCORE=$((SCORE-15)); } || echo '  ✓ No TODOs' && grep -q 'console.log' \"$FILE\" 2>/dev/null && { echo '  ⚠️  console.log (-5)'; SCORE=$((SCORE-5)); } || echo '  ✓ No console.log' && grep -qE 'mock|Mock|placeholder' \"$FILE\" 2>/dev/null && { echo '  ❌ Mock detected (-25)'; SCORE=$((SCORE-25)); } || echo '  ✓ No mocks' && echo \"📊 Manual Score: $SCORE/100\" && echo '' && echo '🔬 Claude Flow Truth Analysis:' && npx claude-flow@alpha truth --report --agent coder 2>/dev/null | head -10 || echo '  Claude Flow not available'"
    }]
  }]
}

Security-Focused Hooks

Detect potential security issues in commands:

{
  "PreToolUse": [{
    "matcher": "Bash",
    "hooks": [{
      "type": "command",
      "command": "CMD=$(cat | jq -r '.tool_input.command // empty') && echo \"$CMD\" | grep -qE 'export.*(KEY|TOKEN|SECRET|PASSWORD)' && echo '⚠️  SECURITY WARNING: Potential secret exposure!' || true"
    }]
  }]
}

✅ Real Example Output

When Creating a File with Issues

PreToolUse Hook Output:

🎯 PRE-EDIT VERIFICATION
Target: /workspaces/flow-cloud/test-hooks.js
⚠️  REQUIREMENTS:
  • Real implementations only (no mocks in production)
  • No hardcoded secrets - use environment variables
  • Complete error handling
  • Secure protocols (HTTPS)

PostToolUse Hook Output:

✅ POST-EDIT ANALYSIS
Modified: /workspaces/flow-cloud/test-hooks.js
Security Check Results:
  ⚠️  TODO comments found
  ⚠️  console.log detected
  🚨 Hardcoded password!

📊 Claude Flow Verification:
   ✅ compile: 1.00
   ❌ test: 0.60
   ✅ lint: 1.00
   📊 Verification Score: 0.90/0.85
   Status: ✅ PASSED
   Overall Average: 0.9 (threshold: 0.85)

⚙️ Benefits

The verification commands add quantitative analysis to the qualitative checklist, giving you both human-readable reminders and data-driven confidence scores.

🔧 Troubleshooting

If Hooks Don't Fire:

1. Restart Claude Code after changing settings.json
2. Validate JSON: jq '.' .claude/settings.json
3. Check permissions format: Use :* not just *
4. Run /doctor to validate settings
5. Check script permissions: chmod +x .claude/hook-analyzer-v2.sh

💡 Remember: The goal is real, secure, functional code - not placeholders or simulations. These hooks keep AI agents focused on production-quality implementations.

🚀 Optional: Claude Flow Integration

For advanced verification with Claude Flow:

Installation

# Install Claude Flow globally
npm install -g claude-flow@alpha

Quick Commands

npx claude-flow@alpha verify init strict  # 0.95 threshold
npx claude-flow@alpha truth               # View scores
npx claude-flow@alpha verify verify "$FILE" --threshold 0.95

📚 Claude Flow Commands Reference

Verify Command (Truth Enforcement)

Initialize verification modes

npx claude-flow@alpha verify init strict          # 0.95 threshold
npx claude-flow@alpha verify init moderate        # 0.85 threshold
npx claude-flow@alpha verify init development     # 0.75 threshold

Run verification on files/tasks

npx claude-flow@alpha verify verify <file> --agent coder --threshold 0.95
npx claude-flow@alpha verify status --recent 10
npx claude-flow@alpha verify rollback --checkpoint last

Truth Command (Score Analytics)

View and analyze scores

npx claude-flow@alpha truth                       # Current scores
npx claude-flow@alpha truth --report              # Detailed report
npx claude-flow@alpha truth --analyze             # Pattern analysis
npx claude-flow@alpha truth --agent coder         # Filter by agent
npx claude-flow@alpha truth --json | jq .averageScore  # For hooks

📝 Key Takeaways

✅ PreToolUse prevents errors before edits happen
✅ PostToolUse enforces checks right after changes
✅ Claude Flow verification provides truth-based enforcement at a 0.95 threshold
✅ Security hooks stop secrets from leaking
✅ Quantitative + qualitative = code that is real, secure, and production-ready

By building these checks into Claude Code, you shift from reactive debugging to proactive verification.