🐛 Bug: useCopilotChat reloadMessages and reset not working

[copilotkit-support]

♻️ Reproduction Steps

1. Use LangGraph Python as the backend agent server with Copilotkit and langgraph up with port 8123.
2. Connect to localhost:8123 in CopilotRuntime (route.ts)

const runtime = new CopilotRuntime({
  remoteEndpoints: [
    langGraphPlatformEndpoint({
      deploymentUrl: process.env.LANGGRAPH_DEPLOYMENT_URL || 'http://localhost:8123', // matches langgraph dev port
      langsmithApiKey: process.env.LANGSMITH_API_KEY || '',
      agents: [{ name: 'demo_agent', description: 'A Demo LLM agent.' }],
    }),
  ],
});

3. Run reloadMessages and reset in useCopilotChat()

const {
  visibleMessages,
  appendMessage,
  setMessages,
  deleteMessage,
  stopGeneration,
  isLoading,
  reloadMessages,
  reset,
} = useCopilotChat();

<button onClick={() => reloadMessages(msg.id)}>Reload Message</button>
<button onClick={reset}>Reset</button>

✅ Expected Behavior

reloadMessages

Regenerate the target msg and continue chat.

reset

Reset the entire thread.

❌ Actual Behavior

reloadMessages

It doesn't regenerate but only remove the target message. Typing new chat message returns backend error.
ValueError: Message dict must contain 'role' and 'content' keys, got {'lc': 1, 'type': 'constructor', 'id': ['langchain_core', 'messages', 'RemoveMessage'], 'kwargs': {'id': 'ck-dd1f6760-1f39-44da-91f6-af1e0de5b166', 'content': '', 'additional_kwargs': {}, 'response_metadata': {}}}

reset

Typing new chat message returns backend error after resetting the chat. Error returned:
ValueError: Message dict must contain 'role' and 'content' keys, got {'lc': 1, 'type': 'constructor', 'id': ['langchain_core', 'messages', 'RemoveMessage'], 'kwargs': {'id': 'ck-dd1f6760-1f39-44da-91f6-af1e0de5b166', 'content': '', 'additional_kwargs': {}, 'response_metadata': {}}}

𝌚 CopilotKit Version

1.9.1

📄 Logs (Optional)

Both errors point to the langchain_core function RemoveMessage.

[copilotkit-support]

🤖 Automated Analysis

• The Python LangGraph adapter expects every element in the messages array it receives to be one of CopilotKit’s message types (TextMessage, ActionExecutionMessage, ResultMessage, AgentStateMessage …).
– For a TextMessage the dict must contain role and content.
– When useCopilotChat.reloadMessages() or reset() truncate the chat history they keep any Agent-state / Action-Execution objects that precede the last user message.
– Those objects do not have role or content, but after the history is serialised by the runtime client and re-expanded on the Python side they land in the generic “text” branch of copilotkit_messages_to_langchain, which raises `ValueError("Message dict missing 'role' and 'content'").

• This only shows up with LangGraph-Python back-ends because that conversion function is part of copilotkit.langgraph (JS back-ends use a different path).

How to solve

1. Upgrade – the fix landed in:
   • JS packages ≥ @copilotkit/* 1.9.3 (runtime filters non-text messages before calling reload)
   • Python SDK ≥ copilotkit 0.1.32 (converter ignores dicts that are not valid TextMessages instead of throwing).

2. Or patch locally until you can update:

// after importing useCopilotChat
const { reloadMessages, visibleMessages, … } = useCopilotChat();

const safeReload = async (id: string) => {
  // keep only text & image messages – drop agent-state / tool messages
  const msgs = visibleMessages.filter(m => m.isTextMessage() || m.isImageMessage());
  setMessages(msgs);
  await reloadMessages(id);        // now backend gets only valid dicts
};

3. If you maintain the Python endpoint, replace

if message["type"] == "TextMessage":
    # …

with a guard that verifies the keys first:

if message.get("type") == "TextMessage" and "role" in message and "content" in message:
    …

References
• Docs – reload/reset behaviour: https://docs.copilotkit.ai/reference/hooks/useCopilotChat
• Fix in Python SDK: copilotkit/langgraph.py (v0.1.32) – silently skip non-text dicts.
• JS side filter: packages/runtime-client-gql/src/client/conversion.ts#filterAgentStateMessages (≥ 1.9.3).

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This comment was generated by the CopilotKit Support Bot