diff --git a/swh/provenance/model.py b/swh/provenance/model.py
index 89122c6..f3b0226 100644
--- a/swh/provenance/model.py
+++ b/swh/provenance/model.py
@@ -1,75 +1,84 @@
 # Copyright (C) 2021  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 from datetime import datetime
 from typing import Iterable, List, Optional, Union
 
 from .archive import ArchiveInterface
 
 
 class OriginEntry:
     def __init__(self, url, revisions: Iterable["RevisionEntry"], id=None):
         self.id = id
         self.url = url
         self.revisions = revisions
 
 
 class RevisionEntry:
     def __init__(
         self,
         id: bytes,
         date: Optional[datetime] = None,
         root: Optional[bytes] = None,
         parents: Optional[Iterable[bytes]] = None,
     ):
         self.id = id
         self.date = date
         assert self.date is None or self.date.tzinfo is not None
         self.root = root
         self._parents = parents
         self._nodes: List[RevisionEntry] = []
 
     def parents(self, archive: ArchiveInterface):
         if self._parents is None:
             revision = archive.revision_get([self.id])
             if revision:
                 self._parents = revision[0].parents
         if self._parents and not self._nodes:
             self._nodes = [
                 RevisionEntry(
                     id=rev.id,
                     root=rev.directory,
                     date=rev.date,
                     parents=rev.parents,
                 )
                 for rev in archive.revision_get(self._parents)
                 if rev
             ]
         yield from self._nodes
 
+    def __str__(self):
+        return f"<MRevision[{self.id.hex()}] {self.date.isoformat()}>"
+
 
 class DirectoryEntry:
     def __init__(self, id: bytes, name: bytes = b""):
         self.id = id
         self.name = name
         self._children: Optional[List[Union[DirectoryEntry, FileEntry]]] = None
 
     def ls(self, archive: ArchiveInterface):
         if self._children is None:
             self._children = []
             for child in archive.directory_ls(self.id):
                 if child["type"] == "dir":
                     self._children.append(
                         DirectoryEntry(child["target"], name=child["name"])
                     )
                 elif child["type"] == "file":
                     self._children.append(FileEntry(child["target"], child["name"]))
         yield from self._children
 
+    def __str__(self):
+        return f"<MDirectory[{self.id.hex()}] {self.name}>"
+
 
 class FileEntry:
     def __init__(self, id: bytes, name: bytes):
         self.id = id
         self.name = name
+
+    def __str__(self):
+        return f"<MFile[{self.id.hex()}] {self.name}>"