Bug: Running Tools in parallel within LangGraph returns a "does not match existing tool call" error

[jfturcot]

I am running into an issue with parallel executions of tools within LangGraph.

You can easily reproduce the issue by running the following graph:
https://github.com/langchain-ai/langchain-academy/tree/main/module-6/deployment

Using this graph, when sending a prompt like "My name is John," it will send you to the update_profile node, which uses Trustcall to update a JSON payload in its memory to store some information about the user. Trustcall runs a Tool called PatchDoc, but the update_profile also runs a Profile Tool.

Doing so raises this error:

Error: Tool call name call_NAnT466ldLHgmgBdeA3xoS6E Profile does not match existing tool call PatchDoc

The issue seems to be within the joinExternalMessages function on the file runtimes/external-store/external-message-converter.tsx that does not expect to receive messages from 2 different tools before one is completed.

[Yonom]

Thank you for reporting this! I am able to reproduce this issue and am working on a fix