diff --git a/tools/build_refactor_inventory.py b/tools/build_refactor_inventory.py
new file mode 100644
index 0000000..22e38f5
--- /dev/null
+++ b/tools/build_refactor_inventory.py
@@ -0,0 +1,55 @@
+#!/usr/bin/env python3
+import ast
+import json
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+TARGETS = [
+    ROOT / "grok_register_ttk.py",
+    ROOT / "registration_flow.py",
+    ROOT / "cpa_xai" / "browser_confirm.py",
+    ROOT / "cpa_export.py",
+    ROOT / "cf_mail_debug.py",
+    ROOT / "cpa_xai" / "oauth_device.py",
+    ROOT / "cpa_xai" / "proxyutil.py",
+]
+
+
+def free_names(node):
+    assigned = set()
+    loaded = set()
+    for child in ast.walk(node):
+        if isinstance(child, ast.Name):
+            if isinstance(child.ctx, (ast.Store, ast.Param)):
+                assigned.add(child.id)
+            elif isinstance(child.ctx, ast.Load):
+                loaded.add(child.id)
+        elif isinstance(child, (ast.FunctionDef, ast.AsyncFunctionDef, ast.ClassDef)) and child is not node:
+            assigned.add(child.name)
+    return sorted(loaded - assigned)
+
+out = {}
+for path in TARGETS:
+    if not path.exists():
+        continue
+    text = path.read_text(encoding="utf-8")
+    tree = ast.parse(text, filename=str(path))
+    entries = []
+    for node in tree.body:
+        if isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef, ast.ClassDef)):
+            entries.append({
+                "kind": type(node).__name__,
+                "name": node.name,
+                "start": node.lineno,
+                "end": getattr(node, "end_lineno", node.lineno),
+                "free_names": free_names(node),
+            })
+    out[str(path.relative_to(ROOT))] = {
+        "lines": len(text.splitlines()),
+        "definitions": entries,
+    }
+
+(ROOT / "refactor_inventory.json").write_text(
+    json.dumps(out, ensure_ascii=False, indent=2) + "\n", encoding="utf-8"
+)
+print("inventory written")