[verified] fix: preserve timestamps in chat history

plugin/pheby/hermes_bridge.py

@@ -9,6 +9,7 @@ so the module can be imported by unit tests without a Hermes install.
 from __future__ import annotations
 
 import asyncio
+import datetime as dt
 import logging
 import threading
 import time
@@ -206,8 +207,10 @@ async def list_conversations(server: Any = None) -> List[Dict[str, Any]]:
 
 def _iso(value: Any) -> Optional[str]:
     try:
+        if isinstance(value, (int, float)):
+            return dt.datetime.fromtimestamp(value, tz=dt.timezone.utc).isoformat()
         return value.isoformat() if value else None
-    except AttributeError:
+    except (AttributeError, OSError, OverflowError, TypeError, ValueError):
         return None
 
 
@@ -254,8 +257,7 @@ async def conversation_history(conversation_id: str, limit: int
                     if isinstance(row.get("_row_id"), (int, str)) else None,
                     "role": role,
                     "text": text,
-                    "ts": row.get("timestamp") if isinstance(
+                    "ts": _iso(row.get("timestamp")),
-                        row.get("timestamp"), str) else None,
                 })
             found = True
         except Exception:

tests/test_pheby.py

@@ -432,6 +432,32 @@ class TestAttachments:
 # Tool events / approvals / clarifications / cancellation (bridge)
 # ═══════════════════════════════════════════════════════════════════════════
 class TestBridge:
+    @pytest.mark.asyncio
+    async def test_history_converts_numeric_hermes_timestamps_to_iso(self, monkeypatch):
+        from pheby import hermes_bridge as hb
+
+        class Store:
+            def peek_session_id(self, _key):
+                return "session-1"
+
+        class DB:
+            def get_messages_as_conversation(self, _session_id, include_row_ids=False):
+                assert include_row_ids is True
+                return [
+                    {"_row_id": 10, "role": "user", "content": "hello", "timestamp": 1_789_000_000.25},
+                    {"_row_id": 11, "role": "assistant", "content": "reply", "timestamp": 1_789_000_001.5},
+                ]
+
+        monkeypatch.setattr(hb, "_session_store", lambda: Store())
+        monkeypatch.setattr(hb, "_session_db", lambda: DB())
+
+        history, found = await hb.conversation_history("conv", 20)
+
+        assert found is True
+        assert [message["message_id"] for message in history] == ["m10", "m11"]
+        assert history[0]["ts"] == "2026-09-10T00:26:40.250000+00:00"
+        assert history[1]["ts"] == "2026-09-10T00:26:41.500000+00:00"
+
     @pytest.mark.asyncio
     async def test_tool_start_event_is_structured_not_text(self, tmp_path,
                                                             monkeypatch):