fix(acp): replay native todo plans

acp_adapter/events.py

@@ -25,6 +25,17 @@ from .tools import (
 logger = logging.getLogger(__name__)
 
 
+def _json_loads_maybe_prefix(value: str) -> Any:
+    """Parse a JSON object even when Hermes appended a human hint after it."""
+    text = value.strip()
+    try:
+        return json.loads(text)
+    except Exception:
+        decoder = json.JSONDecoder()
+        data, _ = decoder.raw_decode(text)
+        return data
+
+
 def _build_plan_update_from_todo_result(result: Any) -> AgentPlanUpdate | None:
     """Translate Hermes' todo tool result into ACP's native plan update.
 
@@ -37,13 +48,17 @@ def _build_plan_update_from_todo_result(result: Any) -> AgentPlanUpdate | None:
         return None
 
     try:
-        data = json.loads(result)
+        data = _json_loads_maybe_prefix(result)
     except Exception:
         return None
 
     if not isinstance(data, dict) or not isinstance(data.get("todos"), list):
         return None
 
+    todos = data["todos"]
+    if not todos:
+        return AgentPlanUpdate(session_update="plan", entries=[])
+
     status_map = {
         "pending": "pending",
         "in_progress": "in_progress",
@@ -54,7 +69,7 @@ def _build_plan_update_from_todo_result(result: Any) -> AgentPlanUpdate | None:
         "cancelled": "completed",
     }
     entries: list[PlanEntry] = []
-    for item in data["todos"]:
+    for item in todos:
         if not isinstance(item, dict):
             continue
         content = str(item.get("content") or item.get("id") or "").strip()
@@ -66,8 +81,6 @@ def _build_plan_update_from_todo_result(result: Any) -> AgentPlanUpdate | None:
             content = f"[cancelled] {content}"
         entries.append(PlanEntry(content=content, priority="medium", status=status))
 
-    if not entries:
-        return None
     return AgentPlanUpdate(session_update="plan", entries=entries)
 
 

acp_adapter/server.py

@@ -59,6 +59,7 @@ from acp.schema import (
 
 from acp_adapter.auth import TERMINAL_SETUP_AUTH_METHOD_ID, build_auth_methods, detect_provider
 from acp_adapter.events import (
+    _build_plan_update_from_todo_result,
     make_message_cb,
     make_step_cb,
     make_thinking_cb,
@@ -910,15 +911,20 @@ class HermesACPAgent(acp.Agent):
                 if not tool_call_id or not tool_name:
                     continue
                 result = message.get("content")
+                result_text = result if isinstance(result, str) else None
                 if not await _send(
                     build_tool_complete(
                         tool_call_id,
                         tool_name,
-                        result=result if isinstance(result, str) else None,
+                        result=result_text,
                         function_args=function_args,
                     )
                 ):
                     return
+                if tool_name == "todo":
+                    plan_update = _build_plan_update_from_todo_result(result_text)
+                    if plan_update is not None and not await _send(plan_update):
+                        return
 
     async def new_session(
         self,