fix: address CodeRabbit review — convert to PreToolUse, add type annotations, logging

Critical fixes: - Convert hook from PostToolUse to PreToolUse so exit(2) blocking works - Change all python references to python3 for cross-platform compat - Add insaits-security-wrapper.js to bridge run-with-flags.js to Python Standard fixes: - Wrap hook with run-with-flags.js so users can disable via ECC_DISABLED_HOOKS="pre:insaits-security" - Add "async": true to hooks.json entry - Add type annotations to all function signatures (Dict, List, Tuple, Any) - Replace all print() statements with logging module (stderr) - Fix silent OSError swallow in write_audit — now logs warning - Remove os.environ.setdefault('INSAITS_DEV_MODE') — pass dev_mode=True through monitor constructor instead - Update hooks/README.md: moved to PreToolUse table, "detects" not "catches", clarify blocking vs non-blocking behavior Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-03-30 13:43:26 +08:00 · 2026-03-10 17:52:44 +01:00
parent 540f738cc7
commit 44dc96d2c6
5 changed files with 166 additions and 76 deletions
--- a/scripts/hooks/insaits-security-monitor.py
+++ b/scripts/hooks/insaits-security-monitor.py
@@ -1,11 +1,11 @@
 #!/usr/bin/env python3
 """
-InsAIts Security Monitor — PostToolUse Hook for Claude Code
+InsAIts Security Monitor -- PreToolUse Hook for Claude Code
 ============================================================

-Real-time security monitoring for Claude Code tool outputs.
-Catches credential exposure, prompt injection, behavioral anomalies,
-hallucination chains, and 20+ other anomaly types — runs 100% locally.
+Real-time security monitoring for Claude Code tool inputs.
+Detects credential exposure, prompt injection, behavioral anomalies,
+hallucination chains, and 20+ other anomaly types -- runs 100% locally.

 Writes audit events to .insaits_audit_session.jsonl for forensic tracing.

@@ -15,13 +15,13 @@ Setup:
  Add to .claude/settings.json:
  {
    "hooks": {
-      "PostToolUse": [
+      "PreToolUse": [
        {
          "matcher": ".*",
          "hooks": [
            {
              "type": "command",
-              "command": "python scripts/hooks/insaits-security-monitor.py"
+              "command": "python3 scripts/hooks/insaits-security-monitor.py"
            }
          ]
        }
@@ -30,73 +30,97 @@ Setup:
  }

 How it works:
-  Claude Code passes tool result as JSON on stdin.
-  This script runs InsAIts anomaly detection on the output.
+  Claude Code passes tool input as JSON on stdin.
+  This script runs InsAIts anomaly detection on the content.
  Exit code 0 = clean (pass through).
-  Exit code 2 = critical issue found (blocks action, shows feedback to Claude).
+  Exit code 2 = critical issue found (blocks tool execution).
+  Stderr output = non-blocking warning shown to Claude.

 Detections include:
-  - Credential exposure (API keys, tokens, passwords in output)
+  - Credential exposure (API keys, tokens, passwords)
  - Prompt injection patterns
  - Hallucination indicators (phantom citations, fact contradictions)
  - Behavioral anomalies (context loss, semantic drift)
  - Tool description divergence
  - Shorthand emergence / jargon drift

-All processing is local — no data leaves your machine.
+All processing is local -- no data leaves your machine.

-Author: Cristi Bogdan — YuyAI (https://github.com/Nomadu27/InsAIts)
+Author: Cristi Bogdan -- YuyAI (https://github.com/Nomadu27/InsAIts)
 License: Apache 2.0
 """

-import sys
-import json
-import os
+from __future__ import annotations
+
 import hashlib
+import json
+import logging
+import os
+import sys
 import time
+from typing import Any, Dict, List, Optional, Tuple
+
+# Configure logging to stderr so it does not interfere with stdout protocol
+logging.basicConfig(
+    stream=sys.stderr,
+    format="[InsAIts] %(message)s",
+    level=logging.DEBUG if os.environ.get("INSAITS_VERBOSE") else logging.WARNING,
+)
+log = logging.getLogger("insaits-hook")

 # Try importing InsAIts SDK
 try:
    from insa_its import insAItsMonitor
-    INSAITS_AVAILABLE = True
+    INSAITS_AVAILABLE: bool = True
 except ImportError:
    INSAITS_AVAILABLE = False

-AUDIT_FILE = ".insaits_audit_session.jsonl"
+AUDIT_FILE: str = ".insaits_audit_session.jsonl"


-def extract_content(data):
-    """Extract inspectable text from a Claude Code tool result."""
-    tool_name = data.get("tool_name", "")
-    tool_input = data.get("tool_input", {})
-    tool_result = data.get("tool_response", {})
+def extract_content(data: Dict[str, Any]) -> Tuple[str, str]:
+    """Extract inspectable text from a Claude Code tool input payload.

-    text = ""
-    context = ""
+    Returns:
+        A (text, context) tuple where *text* is the content to scan and
+        *context* is a short label for the audit log.
+    """
+    tool_name: str = data.get("tool_name", "")
+    tool_input: Dict[str, Any] = data.get("tool_input", {})
+    tool_result: Any = data.get("tool_response", {})
+
+    text: str = ""
+    context: str = ""

    if tool_name in ("Write", "Edit", "MultiEdit"):
        text = tool_input.get("content", "") or tool_input.get("new_string", "")
-        context = "file:" + tool_input.get("file_path", "")[:80]
+        context = "file:" + str(tool_input.get("file_path", ""))[:80]
    elif tool_name == "Bash":
+        command: str = str(tool_input.get("command", ""))
+        # For PreToolUse we inspect the command itself
+        text = command
+        # Also check tool_response if present (for flexibility)
        if isinstance(tool_result, dict):
-            text = tool_result.get("output", "") or tool_result.get("stdout", "")
-        elif isinstance(tool_result, str):
-            text = tool_result
-        context = "bash:" + str(tool_input.get("command", ""))[:80]
+            output = tool_result.get("output", "") or tool_result.get("stdout", "")
+            if output:
+                text = text + "\n" + output
+        elif isinstance(tool_result, str) and tool_result:
+            text = text + "\n" + tool_result
+        context = "bash:" + command[:80]
    elif "content" in data:
-        content = data["content"]
+        content: Any = data["content"]
        if isinstance(content, list):
            text = "\n".join(
                b.get("text", "") for b in content if b.get("type") == "text"
            )
        elif isinstance(content, str):
            text = content
-        context = data.get("task", "")
+        context = str(data.get("task", ""))

    return text, context


-def write_audit(event):
+def write_audit(event: Dict[str, Any]) -> None:
    """Append an audit event to the JSONL audit log."""
    try:
        event["timestamp"] = time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime())
@@ -105,20 +129,24 @@ def write_audit(event):
        ).hexdigest()[:16]
        with open(AUDIT_FILE, "a", encoding="utf-8") as f:
            f.write(json.dumps(event) + "\n")
-    except OSError:
-        pass
+    except OSError as exc:
+        log.warning("Failed to write audit log %s: %s", AUDIT_FILE, exc)


-def format_feedback(anomalies):
-    """Format detected anomalies as feedback for Claude Code."""
-    lines = [
-        "== InsAIts Security Monitor — Issues Detected ==",
+def format_feedback(anomalies: List[Any]) -> str:
+    """Format detected anomalies as feedback for Claude Code.
+
+    Returns:
+        A human-readable multi-line string describing each finding.
+    """
+    lines: List[str] = [
+        "== InsAIts Security Monitor -- Issues Detected ==",
        "",
    ]
    for i, a in enumerate(anomalies, 1):
-        sev = getattr(a, "severity", "MEDIUM")
-        atype = getattr(a, "type", "UNKNOWN")
-        detail = getattr(a, "detail", "")
+        sev: str = getattr(a, "severity", "MEDIUM")
+        atype: str = getattr(a, "type", "UNKNOWN")
+        detail: str = getattr(a, "detail", "")
        lines.extend([
            f"{i}. [{sev}] {atype}",
            f"   {detail[:120]}",
@@ -132,40 +160,38 @@ def format_feedback(anomalies):
    return "\n".join(lines)


-def main():
-    raw = sys.stdin.read().strip()
+def main() -> None:
+    """Entry point for the Claude Code PreToolUse hook."""
+    raw: str = sys.stdin.read().strip()
    if not raw:
        sys.exit(0)

    try:
-        data = json.loads(raw)
+        data: Dict[str, Any] = json.loads(raw)
    except json.JSONDecodeError:
        data = {"content": raw}

    text, context = extract_content(data)

-    # Skip very short or binary content
+    # Skip very short content (e.g. "OK", empty bash results)
    if len(text.strip()) < 10:
        sys.exit(0)

    if not INSAITS_AVAILABLE:
-        print(
-            "[InsAIts] Not installed. Run: pip install insa-its",
-            file=sys.stderr,
-        )
+        log.warning("Not installed. Run: pip install insa-its")
        sys.exit(0)

-    # Enable dev mode (no API key needed for local detection)
-    os.environ.setdefault("INSAITS_DEV_MODE", "true")
-
-    monitor = insAItsMonitor(session_name="claude-code-hook")
-    result = monitor.send_message(
+    monitor: insAItsMonitor = insAItsMonitor(
+        session_name="claude-code-hook",
+        dev_mode=True,
+    )
+    result: Dict[str, Any] = monitor.send_message(
        text=text[:4000],
        sender_id="claude-code",
        llm_id=os.environ.get("INSAITS_MODEL", "claude-opus"),
    )

-    anomalies = result.get("anomalies", [])
+    anomalies: List[Any] = result.get("anomalies", [])

    # Write audit event regardless of findings
    write_audit({
@@ -177,22 +203,23 @@ def main():
    })

    if not anomalies:
-        if os.environ.get("INSAITS_VERBOSE"):
-            print("[InsAIts] Clean — no anomalies.", file=sys.stderr)
+        log.debug("Clean -- no anomalies detected.")
        sys.exit(0)

-    # Check severity
-    has_critical = any(
+    # Determine maximum severity
+    has_critical: bool = any(
        getattr(a, "severity", "") in ("CRITICAL", "critical") for a in anomalies
    )

-    feedback = format_feedback(anomalies)
+    feedback: str = format_feedback(anomalies)

    if has_critical:
-        print(feedback)  # stdout -> Claude Code shows to model
-        sys.exit(2)      # block action
+        # stdout feedback -> Claude Code shows to the model
+        sys.stdout.write(feedback + "\n")
+        sys.exit(2)  # PreToolUse exit 2 = block tool execution
    else:
-        print(feedback, file=sys.stderr)  # stderr -> logged only
+        # Non-critical: warn via stderr (non-blocking)
+        log.warning("\n%s", feedback)
        sys.exit(0)


--- a/scripts/hooks/insaits-security-wrapper.js
+++ b/scripts/hooks/insaits-security-wrapper.js
@@ -0,0 +1,62 @@
+#!/usr/bin/env node
+/**
+ * InsAIts Security Monitor — wrapper for run-with-flags compatibility.
+ *
+ * This thin wrapper receives stdin from the hooks infrastructure and
+ * delegates to the Python-based insaits-security-monitor.py script.
+ *
+ * The wrapper exists because run-with-flags.js spawns child scripts
+ * via `node`, so a JS entry point is needed to bridge to Python.
+ */
+
+'use strict';
+
+const path = require('path');
+const { spawnSync } = require('child_process');
+
+const MAX_STDIN = 1024 * 1024;
+
+let raw = '';
+process.stdin.setEncoding('utf8');
+process.stdin.on('data', chunk => {
+  if (raw.length < MAX_STDIN) {
+    raw += chunk.substring(0, MAX_STDIN - raw.length);
+  }
+});
+
+process.stdin.on('end', () => {
+  const scriptDir = __dirname;
+  const pyScript = path.join(scriptDir, 'insaits-security-monitor.py');
+
+  // Try python3 first (macOS/Linux), fall back to python (Windows)
+  const pythonCandidates = ['python3', 'python'];
+  let result;
+
+  for (const pythonBin of pythonCandidates) {
+    result = spawnSync(pythonBin, [pyScript], {
+      input: raw,
+      encoding: 'utf8',
+      env: process.env,
+      cwd: process.cwd(),
+      timeout: 14000,
+    });
+
+    // ENOENT means binary not found — try next candidate
+    if (result.error && result.error.code === 'ENOENT') {
+      continue;
+    }
+    break;
+  }
+
+  if (!result || (result.error && result.error.code === 'ENOENT')) {
+    process.stderr.write('[InsAIts] python3/python not found. Install Python 3.9+ and: pip install insa-its\n');
+    process.stdout.write(raw);
+    process.exit(0);
+  }
+
+  if (result.stdout) process.stdout.write(result.stdout);
+  if (result.stderr) process.stderr.write(result.stderr);
+
+  const code = Number.isInteger(result.status) ? result.status : 0;
+  process.exit(code);
+});