FAI Hooks Deep Dive

{
  "version": 1,
  "hooks": [
    {
      "event": "userPromptSubmitted",
      "command": "node scan-secrets.js",
      "description": "Scan user prompts for accidental secret inclusion",
      "env": {
        "HOOK_MODE": "block",
        "PATTERNS_FILE": "secret-patterns.json"
      }
    },
    {
      "event": "sessionEnd",
      "command": "node scan-session-log.js",
      "description": "Scan full session log for secrets before persistence"
    }
  ]
}

#!/usr/bin/env node
const fs = require("fs");

// Read user prompt from stdin
let input = "";
process.stdin.on("data", (chunk) => (input += chunk));
process.stdin.on("end", () => {
  const patterns = [
    /(?:sk|pk|api)[_-]?[a-zA-Z0-9]{20,}/g,          // API keys
    /(?:ghp|gho|ghu|ghs|ghr)_[A-Za-z0-9_]{36,}/g,   // GitHub tokens
    /DefaultEndpointsProtocol=https;Account/g,         // Azure conn strings
    /-----BEGIN (?:RSA )?PRIVATE KEY-----/g,           // Private keys
    /eyJ[A-Za-z0-9-_]+\.eyJ[A-Za-z0-9-_]+/g,        // JWT tokens
  ];

  const mode = process.env.HOOK_MODE || "warn";
  const found = patterns.some((p) => p.test(input));

  if (found) {
    console.error("[secrets-scanner] Potential secret detected in prompt");
    process.exit(mode === "block" ? 1 : 0);
  }

  console.log("[secrets-scanner] Clean — no secrets found");
  process.exit(0);
});

{
  "version": 1,
  "hooks": [
    {
      "event": "preToolUse",
      "command": "node guard-tools.js",
      "description": "Block dangerous terminal commands",
      "env": {
        "HOOK_MODE": "block",
        "BLOCKED_PATTERNS": "rm -rf,DROP TABLE,--force,--no-verify"
      }
    }
  ]
}

hooks/
  fai-01-pii-redactor/       # Runs first — redact PII
  fai-02-secrets-scanner/    # Runs second — scan for secrets
  fai-03-tool-guardian/      # Runs third — check tool safety
  fai-04-cost-guardian/      # Runs fourth — enforce budget
  fai-05-output-validator/   # Runs last — validate response

#!/usr/bin/env node
let input = "";
process.stdin.on("data", (chunk) => (input += chunk));
process.stdin.on("end", () => {
  const { tool, args } = JSON.parse(input);
  const mode = process.env.HOOK_MODE || "block";
  const blocked = (process.env.BLOCKED_PATTERNS || "").split(",");

  // Only inspect terminal commands
  if (tool !== "run_in_terminal") {
    process.exit(0);
  }

  const command = args.command || "";
  const match = blocked.find((p) => command.includes(p.trim()));

  if (match) {
    console.error(
      "[tool-guardian] BLOCKED: " + JSON.stringify(match) +
      " found in command: " + command.substring(0, 80)
    );
    process.exit(mode === "block" ? 1 : 0);
  }

  console.log("[tool-guardian] Allowed: " + tool);
  process.exit(0);
});

{
  "play": "01-enterprise-rag",
  "primitives": {
    "hooks": [
      "fai-secrets-scanner",
      "fai-tool-guardian",
      "fai-pii-redactor",
      "fai-cost-guardian",
      "fai-output-validator"
    ]
  }
}

# 1. Create the hook folder
mkdir -p .github/hooks/my-custom-hook

# 2. Create hooks.json
cat > .github/hooks/my-custom-hook/hooks.json << 'EOF'
{
  "version": 1,
  "hooks": [
    {
      "event": "userPromptSubmitted",
      "command": "node check.js",
      "description": "My custom validation"
    }
  ]
}
EOF

# 3. Create the script (read stdin, exit 0 or 1)
cat > .github/hooks/my-custom-hook/check.js << 'EOF'
let input = "";
process.stdin.on("data", (c) => (input += c));
process.stdin.on("end", () => {
  // Your validation logic here
  const isValid = !input.includes("forbidden-word");
  process.exit(isValid ? 0 : 1);
});
EOF

# 4. Validate
npm run validate:primitives