diff --git a/tests/tools/test_process_registry.py b/tests/tools/test_process_registry.py
index dd69764aa3f72..93c2cfcf82816 100644
--- a/tests/tools/test_process_registry.py
+++ b/tests/tools/test_process_registry.py
@@ -92,6 +92,33 @@ def test_kill_started_since_preserves_preexisting_and_foreign_processes(registry
     ]
 
 
+def test_kill_all_backward_compat_and_exclude_ids(registry):
+    """kill_all keeps its historical default behavior (kill everything for
+    the task, consume_output=False, source='kill_all') and honors the new
+    exclude_ids kwarg that kill_started_since delegates through (#76188)."""
+    a = _make_session(sid="proc_a", task_id="session-a")
+    b = _make_session(sid="proc_b", task_id="session-a")
+    registry._running[a.id] = a
+    registry._running[b.id] = b
+
+    calls = []
+
+    def fake_kill(session_id, **kwargs):
+        calls.append((session_id, kwargs))
+        return {"status": "killed"}
+
+    registry.kill_process = fake_kill
+
+    assert registry.kill_all("session-a", exclude_ids=frozenset({"proc_a"})) == 1
+    assert calls == [
+        ("proc_b", {"source": "kill_all", "consume_output": False})
+    ]
+
+    calls.clear()
+    assert registry.kill_all("session-a") == 2
+    assert sorted(c[0] for c in calls) == ["proc_a", "proc_b"]
+
+
 def _wait_until(predicate, timeout: float = 5.0, interval: float = 0.05) -> bool:
     """Poll a predicate until it returns truthy or the timeout elapses."""
     deadline = time.monotonic() + timeout
diff --git a/tools/process_registry.py b/tools/process_registry.py
index e683a341f6902..fdea8f4762ec5 100644
--- a/tools/process_registry.py
+++ b/tools/process_registry.py
@@ -1617,7 +1617,10 @@ class ProcessRegistry:
         ``consume_output`` is true for explicit tool/RPC kills because their
         caller observes the returned output. Bulk cleanup passes false: it
         discards each result and therefore must not suppress an autonomous
-        output-bearing completion notification.
+        output-bearing completion notification. Exception: abandoned-turn
+        reaping (``kill_started_since``) is bulk cleanup that deliberately
+        passes true — a killed abandoned process must not enqueue a synthetic
+        follow-up that revives work the timeout/interrupt stopped.
         """
         from tools.ansi_strip import strip_ansi
 
@@ -1951,13 +1954,34 @@ class ProcessRegistry:
         *,
         source: str,
     ) -> int:
-        """Kill processes created for ``task_id`` after a prior snapshot."""
-        baseline = frozenset(baseline_ids or ())
+        """Kill processes created for ``task_id`` after a prior snapshot.
+
+        ``consume_output`` is forced on: abandoned-turn output must not
+        enqueue a synthetic follow-up that revives work the timeout
+        deliberately stopped.
+        """
+        return self.kill_all(
+            task_id,
+            exclude_ids=frozenset(baseline_ids or ()),
+            source=source,
+            consume_output=True,
+        )
+
+    def kill_all(
+        self,
+        task_id: Optional[str] = None,
+        *,
+        exclude_ids: frozenset = frozenset(),
+        source: str = "kill_all",
+        consume_output: bool = False,
+    ) -> int:
+        """Kill all running processes, optionally filtered by task_id. Returns count killed."""
         with self._lock:
             targets = [
-                s
-                for s in self._running.values()
-                if s.task_id == task_id and s.id not in baseline and not s.exited
+                s for s in self._running.values()
+                if (task_id is None or s.task_id == task_id)
+                and s.id not in exclude_ids
+                and not s.exited
             ]
 
         killed = 0
@@ -1965,28 +1989,7 @@ class ProcessRegistry:
             result = self.kill_process(
                 session.id,
                 source=source,
-                # Abandoned-turn output must not enqueue a synthetic follow-up
-                # that revives work the timeout deliberately stopped.
-                consume_output=True,
-            )
-            if result.get("status") in {"killed", "already_exited"}:
-                killed += 1
-        return killed
-
-    def kill_all(self, task_id: str = None) -> int:
-        """Kill all running processes, optionally filtered by task_id. Returns count killed."""
-        with self._lock:
-            targets = [
-                s for s in self._running.values()
-                if (task_id is None or s.task_id == task_id) and not s.exited
-            ]
-
-        killed = 0
-        for session in targets:
-            result = self.kill_process(
-                session.id,
-                source="kill_all",
-                consume_output=False,
+                consume_output=consume_output,
             )
             if result.get("status") in {"killed", "already_exited"}:
                 killed += 1