fix(agent): respect ephemeral_system_prompt over stored DB prompt (#58774)

agent/conversation_loop.py

@@ -324,6 +324,15 @@ def _restore_or_build_system_prompt(agent, system_message, conversation_history)
             )
 
     if stored_prompt and _stored_prompt_matches_runtime(agent, stored_prompt):
+        # The user set an explicit personality via /personality or the
+        # caller passed an ephemeral override.  Use it even when a stored
+        # prompt would otherwise match — the user's explicit intent wins
+        # over prefix-cache reuse.  Caching will miss for this turn, but
+        # that is the expected trade-off for a deliberate personality switch
+        # (#58774).
+        if getattr(agent, "ephemeral_system_prompt", None):
+            agent._cached_system_prompt = agent.ephemeral_system_prompt
+            return
         # Continuing session — reuse the exact system prompt from the
         # previous turn so the Anthropic cache prefix matches.
         agent._cached_system_prompt = stored_prompt

scripts/release.py

@@ -67,6 +67,7 @@
     "huanshan5195@users.noreply.github.com": "huanshan5195",  # PR #57601 salvage (custom-provider: emit reasoning_effort at the live CustomProfile path so GLM-5.2/ARK/vLLM/Ollama endpoints receive it; + "max" reasoning level)
     "infinitycrew39@gmail.com": "infinitycrew39",  # PR #56431 salvage (honor live vLLM context limits on local endpoints)
     "jonathan.kovacs999@gmail.com": "CocaKova",  # PR #57692 salvage (cron: run jobs under the profile secret scope so get_secret does not fail-close with UnscopedSecretError under profile isolation)
+    "ishengeqi@163.com": "isheng-eqi",
     "hermes.wanderer@yahoo.com": "trismegistus-wanderer",  # PR #31856 salvage (gateway: defer idle-TTL agent-cache eviction until the session store says the session actually expired, so the expiry watcher can still fire MemoryProvider.on_session_end with the live transcript; #11205)
     "louis@letsfive.io": "Mibayy",  # PR #3243 salvage (/compact alias + preview/aggressive flags for /compress)
     "louis@letsfive.io": "Mibayy",  # PR #3176 salvage (api-server: per-client model routing via model_routes)

tests/agent/test_system_prompt_restore.py

@@ -33,6 +33,9 @@ def _make_agent(session_db=None, prebuilt_prompt: str = "BUILT_PROMPT"):
     agent.platform = "cli"
     agent._session_db = session_db
     agent._build_system_prompt = MagicMock(return_value=prebuilt_prompt)
+    # Explicitly None — MagicMock auto-creates attributes on access, so
+    # getattr(agent, "ephemeral_system_prompt", None) would return a Mock.
+    agent.ephemeral_system_prompt = None
     return agent
 
 
@@ -261,5 +264,49 @@ def test_restored_prompt_is_byte_identical_to_stored(self):
         assert agent._cached_system_prompt.encode("utf-8") == stored.encode("utf-8")
 
 
+class TestEphemeralSystemPromptOverride:
+    """When the caller sets an ephemeral system prompt (e.g. /personality),
+    it must win over the session-DB stored prompt (#58774)."""
+
+    def test_ephemeral_overrides_stored_prompt(self):
+        """ephemeral_system_prompt takes precedence over a matching stored prompt."""
+        stored = "Stored prompt from session DB"
+        db = MagicMock()
+        db.get_session.return_value = {"system_prompt": stored}
+        agent = _make_agent(session_db=db)
+        agent.ephemeral_system_prompt = "Personality: pirate"
+
+        _restore_or_build_system_prompt(agent, None, [{"role": "user", "content": "hi"}])
+
+        assert agent._cached_system_prompt == "Personality: pirate"
+        agent._build_system_prompt.assert_not_called()
+
+    def test_ephemeral_none_does_not_block_restore(self):
+        """ephemeral_system_prompt=None (the default) should still restore from DB."""
+        stored = "Stored prompt from session DB"
+        db = MagicMock()
+        db.get_session.return_value = {"system_prompt": stored}
+        agent = _make_agent(session_db=db)
+        agent.ephemeral_system_prompt = None
+
+        _restore_or_build_system_prompt(agent, None, [{"role": "user", "content": "hi"}])
+
+        assert agent._cached_system_prompt == stored
+        agent._build_system_prompt.assert_not_called()
+
+    def test_ephemeral_empty_string_does_not_block_restore(self):
+        """ephemeral_system_prompt='' should still restore from DB (empty is falsy)."""
+        stored = "Stored prompt from session DB"
+        db = MagicMock()
+        db.get_session.return_value = {"system_prompt": stored}
+        agent = _make_agent(session_db=db)
+        agent.ephemeral_system_prompt = ""
+
+        _restore_or_build_system_prompt(agent, None, [{"role": "user", "content": "hi"}])
+
+        assert agent._cached_system_prompt == stored
+        agent._build_system_prompt.assert_not_called()
+
+
 if __name__ == "__main__":
     pytest.main([__file__, "-v"])