fix(acp): replay native todo plans

tests/acp/test_events.py

@@ -12,6 +12,7 @@ import acp
 from acp.schema import AgentPlanUpdate, ToolCallStart, ToolCallProgress, AgentThoughtChunk, AgentMessageChunk
 
 from acp_adapter.events import (
+    _build_plan_update_from_todo_result,
     _send_update,
     make_message_cb,
     make_step_cb,
@@ -296,7 +297,7 @@ class TestStepCallback:
         }
         mock_send.assert_called_once()
 
-    def test_todo_completion_emits_native_plan_update(self, mock_conn, event_loop_fixture):
+    def test_todo_completion_emits_native_plan_update_after_tool_completion(self, mock_conn, event_loop_fixture):
         from collections import deque
 
         tool_call_ids = {"todo": deque(["tc-todo"])}
@@ -314,9 +315,11 @@ class TestStepCallback:
             cb(1, [{"name": "todo", "result": todo_result}])
 
         updates = [call.args[3] for call in mock_send.call_args_list]
-        plan_updates = [u for u in updates if getattr(u, "session_update", None) == "plan"]
-        assert len(plan_updates) == 1
-        plan = plan_updates[0]
+        assert [getattr(update, "session_update", None) for update in updates] == [
+            "tool_call_update",
+            "plan",
+        ]
+        plan = updates[1]
         assert isinstance(plan, AgentPlanUpdate)
         assert [entry.content for entry in plan.entries] == [
             "Inspect ACP",
@@ -326,6 +329,22 @@ class TestStepCallback:
         assert [entry.status for entry in plan.entries] == ["completed", "in_progress", "completed"]
         assert [entry.priority for entry in plan.entries] == ["medium", "medium", "medium"]
 
+    def test_todo_plan_update_parses_json_with_trailing_hint(self):
+        result = '{"todos":[{"id":"ship","content":"Ship ACP plan","status":"pending"}]}\n\n[Hint: persisted]'
+
+        update = _build_plan_update_from_todo_result(result)
+
+        assert isinstance(update, AgentPlanUpdate)
+        assert [entry.content for entry in update.entries] == ["Ship ACP plan"]
+        assert [entry.status for entry in update.entries] == ["pending"]
+
+    def test_todo_plan_update_with_empty_todos_clears_plan(self):
+        update = _build_plan_update_from_todo_result('{"todos":[],"summary":{"total":0}}')
+
+        assert isinstance(update, AgentPlanUpdate)
+        assert update.session_update == "plan"
+        assert update.entries == []
+
 
 # ---------------------------------------------------------------------------
 # Message callback