diff --git a/agent/moa_loop.py b/agent/moa_loop.py
index 267f33dd7e5a..d8461e921dc2 100644
--- a/agent/moa_loop.py
+++ b/agent/moa_loop.py
@@ -501,8 +501,20 @@ def _reference_messages(messages: list[dict[str, Any]]) -> list[dict[str, Any]]:
                 # a placeholder so the reference knows a non-text turn
                 # happened.
                 text = "[user sent non-text content (e.g. an image attachment)]"
-            if text.strip():
-                last_user_content = text
+            if not text.strip():
+                # Genuinely empty user turn (content="" / None). It carries
+                # nothing advisory, and strict providers (Kimi/Moonshot, ZAI,
+                # and others that enforce non-empty user content) reject it
+                # with 400 "message ... with role 'user' must not be empty" —
+                # the same way the assistant branch below drops turns with no
+                # parts. Lenient providers (DeepSeek) accept the empty turn,
+                # which is why a MoA fan-out would fail on one reference and
+                # pass on another for the identical rendered view. The
+                # advisory view is already not strictly alternating (adjacent
+                # assistant turns occur in every tool loop), so dropping a
+                # contentless turn is safe.
+                continue
+            last_user_content = text
             rendered.append({"role": "user", "content": text})
         elif role == "assistant":
             parts: list[str] = []
diff --git a/tests/run_agent/test_moa_loop_mode.py b/tests/run_agent/test_moa_loop_mode.py
index 094278541762..659f64da7a94 100644
--- a/tests/run_agent/test_moa_loop_mode.py
+++ b/tests/run_agent/test_moa_loop_mode.py
@@ -392,6 +392,44 @@ def test_reference_messages_fresh_user_turn_ends_on_that_user():
     assert view[-1] == {"role": "user", "content": "q2 current"}
 
 
+def test_reference_messages_drops_empty_user_turns():
+    """Empty user turns must not leak into the advisory view.
+
+    A user message whose content is "" or a non-string/multimodal payload
+    (flattened to "" by the text-extraction step) carries nothing advisory.
+    Strict providers (Kimi/Moonshot and others that enforce non-empty user
+    content) reject such a message with
+    400 "message ... with role 'user' must not be empty", while lenient
+    providers (DeepSeek) accept it — so a fan-out over the identical rendered
+    view fails on one reference and passes on another. The renderer must emit
+    NO empty user turn, mirroring how empty assistant turns are dropped.
+    """
+    from agent.moa_loop import _reference_messages
+
+    messages = [
+        {"role": "system", "content": "sys"},
+        {"role": "user", "content": "real question"},
+        {"role": "assistant", "content": "", "tool_calls": [
+            {"function": {"name": "read_file", "arguments": '{"path":"c.yaml"}'}}
+        ]},
+        {"role": "tool", "content": "some result"},
+        {"role": "user", "content": ""},  # empty string user turn
+        {"role": "user", "content": [{"type": "text", "text": "multimodal"}]},  # non-string -> ""
+    ]
+
+    view = _reference_messages(messages)
+
+    # No user turn in the view may be empty/whitespace-only.
+    empty_users = [
+        m for m in view
+        if m.get("role") == "user" and not str(m.get("content", "")).strip()
+    ]
+    assert empty_users == [], f"empty user turn leaked into advisory view: {empty_users}"
+    # The real user prompt survives and the view still ends on a user turn.
+    assert view[0] == {"role": "user", "content": "real question"}
+    assert view[-1]["role"] == "user"
+
+
 def test_run_reference_prepends_advisory_system_prompt(monkeypatch):
     """Each reference call gets the advisory-role system prompt first.