diff --git a/dataset.py b/dataset.py
index 8496b8b..efffe09 100644
--- a/dataset.py
+++ b/dataset.py
@@ -1,7 +1,7 @@
 from dataclasses import dataclass, field
 from enum import Enum
 from typing import Any, Dict, List, Optional
-import json, argparse, os
+import json, argparse, os, uuid
 from utils import prompt_yes_no
 
 # fmt: off
@@ -27,6 +27,7 @@ class Selection:
 
 @dataclass
 class Metadata:
+    id: str
     repo: str   # the name of the repo, with style XXX/YYY
     pr_number: int
     pr_title: str
@@ -49,14 +50,14 @@ class DatasetEntry:
 
 @dataclass
 class CommentGenEntry:
-    id: int
+    id: str
     files: Dict[str, str]   # filename -> file content
     diffs: Dict[str, str]   # filename -> diff, diffs between the opening of the PR and the comment
 
     @staticmethod
-    def from_entry(entry: DatasetEntry, id: int) -> "CommentGenEntry":
+    def from_entry(entry: DatasetEntry) -> "CommentGenEntry":
         return CommentGenEntry(
-            id=id,
+            id=entry.metadata.id,
             files={fname: fdata.content_before_pr for fname, fdata in entry.files.items()},
             diffs=entry.diffs_before,
         )
@@ -64,15 +65,15 @@ class CommentGenEntry:
 
 @dataclass
 class CodeRefinementEntry:
-    id: int
+    id: str
     files: Dict[str, str]   # filename -> file content
     diffs: Dict[str, str]   # filename -> diff, diffs between the opening of the PR and the comment
     comments: List[Comment]
 
     @staticmethod
-    def from_entry(entry: DatasetEntry, id: int) -> "CodeRefinementEntry":
+    def from_entry(entry: DatasetEntry) -> "CodeRefinementEntry":
         return CodeRefinementEntry(
-            id=id,
+            id=entry.metadata.id,
             files={fname: fdata.content_before_pr for fname, fdata in entry.files.items()},
             diffs=entry.diffs_before,
             comments=entry.comments,
@@ -109,7 +110,6 @@ class Dataset:
                 if entry.metadata.selection and entry.metadata.selection.diff_after_address_change
             ]
 
-        entry_counter = -1
         to_dump = Dataset(entries=entries_to_dump)
 
         def transform_entry(entry: DatasetEntry | Dataset | Any) -> dict | list:
@@ -122,13 +122,11 @@ class Dataset:
             if isinstance(entry, Dataset):
                 return entry.entries
 
-            nonlocal entry_counter
-            entry_counter += 1
             if type_ == OutputType.COMMENT_GEN:
-                return CommentGenEntry.from_entry(entry, entry_counter).__dict__
+                return CommentGenEntry.from_entry(entry).__dict__
 
             if type_ == OutputType.CODE_REFINEMENT:
-                return CodeRefinementEntry.from_entry(entry, entry_counter).__dict__
+                return CodeRefinementEntry.from_entry(entry).__dict__
 
         with open(filename, "w", encoding="utf-8") as f:
             json.dump(to_dump, f, default=transform_entry, indent=4)
@@ -146,6 +144,8 @@ class Dataset:
             selection_data = metadata_data["selection"] if "selection" in metadata_data else None
             selection = Selection(**selection_data) if selection_data else None
             metadata_data["selection"] = selection
+            if "id" not in metadata_data:
+                metadata_data["id"] = uuid.uuid4().hex
             metadata = Metadata(**metadata_data)
 
             if (