diff --git a/plugins/code-sentinel/hooks/hooks.json b/plugins/code-sentinel/hooks/hooks.json
index d362360..e03ac7d 100644
--- a/plugins/code-sentinel/hooks/hooks.json
+++ b/plugins/code-sentinel/hooks/hooks.json
@@ -5,8 +5,8 @@
         "matcher": "Write|Edit|MultiEdit",
         "hooks": [
           {
-            "type": "prompt",
-            "prompt": "[code-sentinel] SECURITY CHECK - STRICT OUTPUT FORMAT:\n\nSKIP entirely for: *.md, *.json, *.yml, *.yaml, *.txt, README, CHANGELOG, LICENSE, docs/*\n\nFor CODE files (.py, .js, .ts, .sh, etc.), check for:\n- eval()/exec() with user input\n- SQL string concatenation\n- shell=True with user input\n- Hardcoded secrets (actual keys/passwords, not placeholders)\n- Pickle/marshal deserialization of untrusted data\n- innerHTML/dangerouslySetInnerHTML with user content\n\nOutput Format (MANDATORY):\n- Critical found: '[code-sentinel] BLOCKED: {10 words max}'\n- Warning found: '[code-sentinel] Warning: {brief reason}. Proceeding.'\n- Clean/config files: Say nothing (empty response)\n\nALL outputs MUST start with '[code-sentinel]' - NO EXCEPTIONS.\nNEVER block docs/config. NEVER do lengthy analysis."
+            "type": "command",
+            "command": "${CLAUDE_PLUGIN_ROOT}/hooks/security-check.sh"
           }
         ]
       }
diff --git a/plugins/code-sentinel/hooks/security-check.sh b/plugins/code-sentinel/hooks/security-check.sh
new file mode 100755
index 0000000..643c5d6
--- /dev/null
+++ b/plugins/code-sentinel/hooks/security-check.sh
@@ -0,0 +1,62 @@
+#!/bin/bash
+# code-sentinel security check hook
+# Checks for obvious security issues in code files, skips config/docs
+# Command hook - guaranteed predictable behavior
+
+# Read tool input from stdin
+INPUT=$(cat)
+
+# Extract file_path from JSON input
+FILE_PATH=$(echo "$INPUT" | grep -o '"file_path"[[:space:]]*:[[:space:]]*"[^"]*"' | head -1 | sed 's/.*"file_path"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/')
+
+# If no file_path, exit silently
+if [ -z "$FILE_PATH" ]; then
+    exit 0
+fi
+
+# SKIP config/doc files entirely - exit silently
+case "$FILE_PATH" in
+    *.md|*.json|*.yml|*.yaml|*.txt|*.toml|*.ini|*.cfg|*.conf)
+        exit 0
+        ;;
+    */docs/*|*/README*|*/CHANGELOG*|*/LICENSE*)
+        exit 0
+        ;;
+    */.claude/*|*/.github/*|*/.vscode/*)
+        exit 0
+        ;;
+esac
+
+# For code files, extract content to check
+# For Edit tool: check new_string
+# For Write tool: check content
+CONTENT=$(echo "$INPUT" | grep -o '"new_string"[[:space:]]*:[[:space:]]*"[^"]*"' | head -1 | sed 's/.*"new_string"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/')
+if [ -z "$CONTENT" ]; then
+    CONTENT=$(echo "$INPUT" | grep -o '"content"[[:space:]]*:[[:space:]]*"[^"]*"' | head -1 | sed 's/.*"content"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/')
+fi
+
+# If no content to check, exit silently
+if [ -z "$CONTENT" ]; then
+    exit 0
+fi
+
+# Check for hardcoded secrets patterns (obvious cases only)
+if echo "$CONTENT" | grep -qiE '(api[_-]?key|api[_-]?secret|password|passwd|secret[_-]?key|auth[_-]?token)[[:space:]]*[=:][[:space:]]*["\x27][A-Za-z0-9+/=_-]{20,}["\x27]'; then
+    echo "[code-sentinel] BLOCKED: Hardcoded secret detected"
+    exit 1
+fi
+
+# Check for AWS keys pattern
+if echo "$CONTENT" | grep -qE 'AKIA[A-Z0-9]{16}'; then
+    echo "[code-sentinel] BLOCKED: AWS access key detected"
+    exit 1
+fi
+
+# Check for private key headers
+if echo "$CONTENT" | grep -qE '\-\-\-\-\-BEGIN (RSA |DSA |EC |OPENSSH )?PRIVATE KEY\-\-\-\-\-'; then
+    echo "[code-sentinel] BLOCKED: Private key detected"
+    exit 1
+fi
+
+# All other cases: exit silently (allow the edit)
+exit 0