--- a/mrjunejune/inference/copilot_sidecar_test.py	Tue Aug 18 19:14:53 2026 -0700
+++ b/mrjunejune/inference/copilot_sidecar_test.py	Tue Aug 18 22:18:15 2026 -0700
@@ -1,5 +1,7 @@
 import asyncio
 import hashlib
+import os
+import tempfile
 import types
 import unittest
 import uuid
@@ -242,6 +244,37 @@
             ["session.warmed", "turn.done"],
         )
 
+    async def test_warm_skips_resume_without_persistence_marker(self):
+        with tempfile.TemporaryDirectory() as state_directory:
+            self.config = replace(
+                self.config,
+                base_directory=state_directory,
+            )
+            sidecar, client = await self.make_sidecar()
+            await sidecar.dispatch(
+                {
+                    "command": "conversation.warm",
+                    "request_id": "warm-persistent",
+                    "conversation_id": "canvas-orchestrator",
+                    "prompt_profile": "canvas_orchestrator",
+                    "prompt_version": 1,
+                    "knowledge_version": 1,
+                }
+            )
+
+            self.assertEqual(len(client.resume_calls), 0)
+            self.assertEqual(len(client.create_calls), 1)
+            session_id = client.create_calls[0][0]
+            self.assertTrue(
+                os.path.isfile(
+                    os.path.join(
+                        state_directory,
+                        ".session-markers",
+                        session_id,
+                    )
+                )
+            )
+
     async def test_warm_rejects_non_boolean_resume_existing(self):
         sidecar, client = await self.make_sidecar()
         await sidecar.dispatch(