diff --git a/scripts/normalize-code-blocks.py b/scripts/normalize-code-blocks.py
new file mode 100644
index 00000000..32f63318
--- /dev/null
+++ b/scripts/normalize-code-blocks.py
@@ -0,0 +1,141 @@
+#!/usr/bin/env python3
+"""
+normalize-code-blocks.py — Fix inconsistent indentation in training data code blocks.
+
+When code blocks are embedded in JSONL as triple-quoted strings, indentation
+accumulates from the surrounding context. This script normalizes code block
+content using textwrap.dedent and consistent 4-space indentation.
+
+Usage:
+    python3 scripts/normalize-code-blocks.py training/data/preference_pairs.jsonl
+    python3 scripts/normalize-code-blocks.py --dry-run training/data/*.jsonl
+    python3 scripts/normalize-code-blocks.py --check training/data/*.jsonl  # CI mode
+"""
+import argparse
+import json
+import re
+import sys
+import textwrap
+from pathlib import Path
+
+# Matches ```python ... ``` or ``` ... ``` blocks inside string values
+CODE_BLOCK_RE = re.compile(
+    r"(?P<open>```(?:python|py|bash|sh|javascript|js|typescript|ts|go|rust|ruby)?\s*\n)"
+    r"(?P<code>.*?)"
+    r"(?P<close>```)",
+    re.DOTALL,
+)
+
+
+def normalize_code_block(match: re.Match) -> str:
+    """Normalize indentation in a single code block."""
+    open_tag = match.group("open")
+    code = match.group("code")
+    close_tag = match.group("close")
+
+    # Skip empty blocks
+    if not code.strip():
+        return match.group(0)
+
+    # Dedent the code
+    dedented = textwrap.dedent(code)
+
+    # Strip leading/trailing blank lines
+    lines = dedented.split("\n")
+    while lines and not lines[0].strip():
+        lines.pop(0)
+    while lines and not lines[-1].strip():
+        lines.pop()
+
+    normalized = "\n".join(lines)
+    return f"{open_tag}{normalized}\n{close_tag}"
+
+
+def process_line(line: str) -> tuple:
+    """Process a single JSONL line. Returns (new_line, num_fixes)."""
+    try:
+        obj = json.loads(line)
+    except json.JSONDecodeError:
+        return line, 0
+
+    fixes = 0
+
+    def fix_strings(obj):
+        nonlocal fixes
+        if isinstance(obj, str):
+            original = obj
+            fixed = CODE_BLOCK_RE.sub(normalize_code_block, obj)
+            if fixed != original:
+                fixes += 1
+            return fixed
+        elif isinstance(obj, dict):
+            return {k: fix_strings(v) for k, v in obj.items()}
+        elif isinstance(obj, list):
+            return [fix_strings(item) for item in obj]
+        return obj
+
+    fixed_obj = fix_strings(obj)
+    return json.dumps(fixed_obj, ensure_ascii=False) + "\n", fixes
+
+
+def process_file(filepath: str, dry_run: bool = False) -> dict:
+    """Process a single JSONL file. Returns stats dict."""
+    path = Path(filepath)
+    if not path.exists():
+        return {"file": filepath, "error": "not found", "fixes": 0, "lines": 0}
+
+    lines = path.read_text(encoding="utf-8").splitlines()
+    fixed_lines = []
+    total_fixes = 0
+
+    for line in lines:
+        if not line.strip():
+            fixed_lines.append(line)
+            continue
+        new_line, fixes = process_line(line)
+        fixed_lines.append(new_line.rstrip("\n"))
+        total_fixes += fixes
+
+    if total_fixes > 0 and not dry_run:
+        path.write_text("\n".join(fixed_lines) + "\n", encoding="utf-8")
+
+    return {
+        "file": filepath,
+        "lines": len(lines),
+        "fixes": total_fixes,
+        "changed": total_fixes > 0,
+    }
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="Normalize code block indentation in JSONL training data"
+    )
+    parser.add_argument("files", nargs="+", help="JSONL files to process")
+    parser.add_argument("--dry-run", action="store_true", help="Show changes without writing")
+    parser.add_argument("--check", action="store_true", help="CI mode: exit 1 if fixes needed")
+    args = parser.parse_args()
+
+    total_fixes = 0
+    results = []
+
+    for filepath in args.files:
+        result = process_file(filepath, dry_run=args.dry_run or args.check)
+        results.append(result)
+        total_fixes += result["fixes"]
+
+        if result["fixes"] > 0:
+            status = "FIXED" if not args.dry_run and not args.check else "WOULD FIX"
+            print(f"  {status}: {result['file']} — {result['fixes']} code blocks normalized")
+        else:
+            print(f"  OK: {result['file']}")
+
+    print(f"\nTotal: {total_fixes} code blocks normalized across {len(results)} files")
+
+    if args.check and total_fixes > 0:
+        print("FAIL: Code block indentation issues found. Run without --check to fix.")
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()