diff --git a/docs/heartbeat-automation-prompt.md b/docs/heartbeat-automation-prompt.md
index b36e22985a..10f160d3fd 100644
--- a/docs/heartbeat-automation-prompt.md
+++ b/docs/heartbeat-automation-prompt.md
@@ -727,9 +727,11 @@ For every automatic heartbeat turn, the agent-facing checklist is:
    Every heartbeat guard commits one idempotent receipt. If
    `effective_action=monitor_quiet_skip`, it also commits the no-spend stall
    observation and returns the follow-up decision; do not append another manual
-   poll. Return quiet `DONT_NOTIFY` if it remains monitor-only. Keep monitor
-   todos visible but do no delivery edits and no spend until material evidence
-   changes or the guard exposes `autonomous_replan_required` /
+   poll. For a monitor-only turn with `DONT_NOTIFY`, leave chat quiet. If the
+   host requires a completion result, use its complete quiet result without
+   additional chat text. A bare decision or skip explanation is not a host
+   result. Keep monitor todos visible and do no delivery edits or spend until
+   material evidence changes or the guard exposes `autonomous_replan_required` /
    `execution_obligation.must_attempt_work=true`.
 3. For `notify_user_on_open_todo=true`, follow the current
    `interaction_contract.user_channel` for the concrete notice and cooldown.
diff --git a/loopx/control_plane/heartbeat/rules.py b/loopx/control_plane/heartbeat/rules.py
index 823e6e9129..d3e607f2c0 100644
--- a/loopx/control_plane/heartbeat/rules.py
+++ b/loopx/control_plane/heartbeat/rules.py
@@ -19,10 +19,14 @@
     "Local outcomes never replace root continuation, budget or stop criteria."
 )
 
+HEARTBEAT_QUIET_COMPLETION_RULE = (
+    "DONT_NOTIFY: no chat text. Return any required host quiet result in full."
+)
 USER_TODO_FINAL_MESSAGE_RULE = (
     f"{OPERATOR_LANGUAGE_RULE} "
     "`interaction_contract.user_channel.notify` controls output: "
-    "NOTIFY=concrete action; DONT_NOTIFY=quiet. "
+    "NOTIFY=concrete action. "
+    f"{HEARTBEAT_QUIET_COMPLETION_RULE} "
     "`should_run`/due monitor/other-agent todos are not user prompts. "
     "Only under NOTIFY, `action_required` without an action: say the specific "
     "user Todo is not projected and repair LoopX state projection. Under "
@@ -31,7 +35,7 @@
 HEARTBEAT_NOTIFICATION_RULE_SHORT = (
     f"{OPERATOR_LANGUAGE_RULE_THIN} "
     "`user_channel.notify` controls OUTPUT only: NOTIFY=show; "
-    "DONT_NOTIFY=no output. "
+    f"{HEARTBEAT_QUIET_COMPLETION_RULE} "
     "`heartbeat_recommendation.agent_must_attempt`/"
     "`execution_obligation.must_attempt_work`: true=work+writeback; only "
     "false permits no-op. Due/peer work is not a user prompt. Missing NOTIFY "
diff --git a/loopx/control_plane/heartbeat/task_body.py b/loopx/control_plane/heartbeat/task_body.py
index 7ef45d1309..e7c4f7473d 100644
--- a/loopx/control_plane/heartbeat/task_body.py
+++ b/loopx/control_plane/heartbeat/task_body.py
@@ -10,6 +10,7 @@
     DEFAULT_MATERIAL_QUEUE_RULE,
     DEFAULT_PERMISSION_RULE,
     HEARTBEAT_NOTIFICATION_RULE_SHORT,
+    HEARTBEAT_QUIET_COMPLETION_RULE,
     HEARTBEAT_TURN_BOOTSTRAP_RULE,
     HEARTBEAT_KNOWN_CHOICE_RULE,
     HEARTBEAT_VISION_WRITEBACK_RULE_SHORT,
@@ -161,8 +162,7 @@ def render_heartbeat_task_body(
   Still do not launch/stop/restart/sync/design code or mutate production unless
   `should_run=true` or the user explicitly authorizes it.
 - Otherwise, do not do implementation work, adapter work, file edits, research,
-  or project exploration in this turn. Return a quiet heartbeat `DONT_NOTIFY`
-  response with the skip reason.
+  or project exploration in this turn. Follow the user-channel rule above.
 
 If the result says `should_run=true`:
 
@@ -367,12 +367,13 @@ def render_compact_heartbeat_task_body(
 `agent_read_required`: drain/read/triage before work; settle/ACK.
 
 Output policy: authority=`interaction_contract.user_channel.notify`;
-external=`NOTIFY`; quiet=`DONT_NOTIFY`; quiet_missing_action=`internal_repair`.
+external=`NOTIFY`; quiet_missing_action=`internal_repair`.
+{HEARTBEAT_QUIET_COMPLETION_RULE}
 
 If `should_run=false`: `monitor_quiet_skip` -> receipt/stall; quiet unless
 replan; failed write -> retry id; no edits/spend; receipts do not self-stop.
 Only under `NOTIFY`, `state=operator_gate`/`notify_user_on_open_todo=true`
-permit concrete blocker-push; else quiet.
+permit concrete blocker-push.
 Honor repeat/cooldown. `safe_bypass_allowed=true`: validate/settle its allowed work.
 Wait: one allowed read-only poll; unchanged quiet, new evidence follows the
 current monitor/auxiliary contract.
@@ -680,9 +681,10 @@ def render_thin_heartbeat_task_body(
 
 {HOST_LOOP_SAFETY_RULE}
 {scope_sentence}
-Use TurnEnvelope: `action.must_attempt` requires work; `user.notify` controls
-output only. ok=false -> recovery, no delivery. Language=user. Honor `boundary`, `execution_policy`, `contract_capsule`,
-`work_context`, remaining `required_reads`, `agent_context`, and `replan_action_packet` when present.
+Use TurnEnvelope: `action.must_attempt`=work; `user.notify`=output only.
+{HEARTBEAT_QUIET_COMPLETION_RULE}
+ok=false: recover, no delivery. Language=user. Honor `boundary`, `execution_policy`, `contract_capsule`,
+`work_context`, remaining `required_reads` and `replan_action_packet` when present.
 When present, read inline `agent_context` before planning. Read `detail_ref.full_decision` for
 selection, replan, missing/truncated commands or an `agent_context.detail_ref`:
 same-invocation observation, not fresh admission.
diff --git a/tests/control_plane/test_heartbeat_agent_input.py b/tests/control_plane/test_heartbeat_agent_input.py
index a37ba7eed7..34940becdf 100644
--- a/tests/control_plane/test_heartbeat_agent_input.py
+++ b/tests/control_plane/test_heartbeat_agent_input.py
@@ -71,6 +71,8 @@ def test_thin_cli_preserves_readable_admission_and_authority_with_host_scope(tmp
     body = packet["task_body"]
     assert "Equal peer `worker-a` (peer_v1)" in body
     assert f"scope: {scope}" in body
+    assert "DONT_NOTIFY: no chat text" in body
+    assert "required host quiet result in full" in body
     assert "quota claim/lease and workspace contract plus repository rules" in body
     assert "Follow todo continuation policy" in body
     assert "Task-scoped coordination grants no authority over other agents" in body
diff --git a/tests/control_plane/test_heartbeat_notification_rule.py b/tests/control_plane/test_heartbeat_notification_rule.py
index e3e47ecca2..a97c336a59 100644
--- a/tests/control_plane/test_heartbeat_notification_rule.py
+++ b/tests/control_plane/test_heartbeat_notification_rule.py
@@ -94,6 +94,23 @@ def test_rendered_task_bodies_keep_execution_obligation_authority() -> None:
         assert "Missing vision: same-turn checkpoint-context" not in body
 
 
+def test_codex_app_quiet_completion_is_host_control_not_chat(tmp_path) -> None:
+    variants = [{mode: True} for mode in ("full", "compact", "brief", "thin")]
+    variants.append({
+        "thin": True, "turn_envelope": True,
+        "decision_output_root": tmp_path, "turn_instance_id": "fixture-quiet-turn",
+    })
+    for variant in variants:
+        body = build_heartbeat_prompt(
+            goal_id="quiet-completion-fixture", agent_id="worker-a",
+            registered_agents=["worker-a"], runtime_profile="codex_app_heartbeat",
+            **variant,
+        )["task_body"]
+        assert "DONT_NOTIFY: no chat text" in body, variant
+        assert "required host quiet result in full" in body, variant
+        assert "response with the skip reason" not in body, variant
+
+
 def test_all_heartbeat_modes_scope_no_spend_to_observation() -> None:
     # Build the shipped payload, including the short/default worker entrypoint.
     # An unchanged artifact may still accompany a validated route elimination;