fix(conversation): clear _mute_post_response on substantive tool-only turn

Salvage of #63888. The original fix clears stale _last_content_with_tools
on substantive tool-only turns but doesn't clear _mute_post_response, which
a prior housekeeping turn may have set. This suppresses tool progress
output via _vprint until the no-tool-call branch resets it at line ~4834
— after all tools have finished executing.

Fix: also reset _mute_post_response = False when clearing stale fallback.

Added test: verify pure housekeeping turns (content + only housekeeping
tools) still set the fallback correctly — the original use case the
fallback was designed for.

Co-authored-by: liuhao1024 <sunsky.lau@gmail.com>

agent/conversation_loop.py

@@ -4695,6 +4695,13 @@ def run_conversation(
                 if assistant_message.tool_calls and not _all_housekeeping:
                     agent._last_content_with_tools = None
                     agent._last_content_tools_all_housekeeping = False
+                    # Also clear the mute flag: a prior housekeeping turn may
+                    # have set _mute_post_response (line ~4667), and the
+                    # substantive tools in THIS turn should produce visible
+                    # progress output. Without this reset, _vprint suppresses
+                    # tool progress until the no-tool-call branch clears it at
+                    # line ~4834 — after all tools have finished.
+                    agent._mute_post_response = False
 
                 # If this turn has both content AND tool_calls, capture the content
                 # as a fallback final response. Common pattern: model delivers its

tests/run_agent/test_conversation_fallback_state.py

@@ -123,4 +123,58 @@ def test_substantive_tool_only_turn_invalidates_older_housekeeping_fallback():
     assert result["turn_exit_reason"].startswith("text_response"), (
         f"Expected text_response exit, got: {result['turn_exit_reason']}. "
         f"This indicates the wrong fallback path was taken."
+    )
+
+
+def test_housekeeping_only_turn_still_sets_fallback():
+    """Regression: pure housekeeping turns (content + only housekeeping tools)
+    must still set the fallback so the post-response mute path works.  This
+    verifies the fix doesn't break the original use case the fallback was
+    designed for.
+    """
+    with (
+        patch("run_agent.get_tool_definitions", return_value=_tool_defs("memory")),
+        patch("run_agent.check_toolset_requirements", return_value={}),
+        patch("run_agent.OpenAI"),
+    ):
+        agent = AIAgent(
+            api_key="test-key",
+            base_url="https://openrouter.ai/api/v1/",
+            quiet_mode=True,
+            skip_context_files=True,
+            skip_memory=True,
+        )
+
+    agent._cached_system_prompt = "You are helpful."
+    agent._use_prompt_caching = False
+    agent.tool_delay = 0
+    agent.compression_enabled = False
+    agent.save_trajectories = False
+    agent.valid_tool_names = {"memory"}
+    agent.client = MagicMock()
+    agent.client.chat.completions.create.side_effect = [
+        # Turn 1: Content + housekeeping tool (should set fallback)
+        _response(
+            content="You're welcome!",
+            finish_reason="tool_calls",
+            tool_calls=[_tool_call("memory", "mem1")],
+        ),
+        # Turn 2: Empty response (should use the housekeeping fallback)
+        _response(content="", finish_reason="stop"),
+    ]
+
+    with (
+        patch("run_agent.handle_function_call", return_value="ok"),
+        patch.object(agent, "_persist_session"),
+        patch.object(agent, "_save_trajectory"),
+        patch.object(agent, "_cleanup_task_resources"),
+    ):
+        result = agent.run_conversation("save this")
+
+    assert result["final_response"] == "You're welcome!", (
+        f"Expected housekeeping fallback content, got: {result['final_response']}. "
+        f"Pure housekeeping turns should still set the fallback."
+    )
+    assert "fallback_prior_turn_content" in result.get("turn_exit_reason", ""), (
+        f"Expected fallback_prior_turn_content exit, got: {result['turn_exit_reason']}."
     )