A Closer Look at Non-deterministic API Responses with LangChain ReAct

LangChain ReAct, a structured chat agent that utilizes the LangChain ReAct API, has been experiencing inconsistent behavior with the GPT-4 model. When querying the VectorDB to retrieve information and provide answers, the agent occasionally fails to recognize the retriever tool action and returns the requested format incorrectly.

To investigate this issue, I delved into the internals of LangChain. Upon examining the Python API call, I discovered that when ‘GPT-4’ is invoked, it internally selects the last snapshot available, which is currently ‘gpt-4-0613’. This selection process is documented, albeit with some ambiguity. The general consensus among the community is that ‘gpt-4’ and ‘gpt-4-0613’ are largely identical, although it is difficult to verify.

Interestingly, using the same prompts, and setting the temperature to 0 and top_p to 0.01 (as a value of 0 is not allowed in the playground), does not guarantee deterministic behavior. This means that even with identical prompts and settings, the model’s responses may still differ.

To demonstrate this inconsistency, I provide both a working example and a failing example, with all parameters and prompts kept exactly the same. These examples showcase the prompts that LangChain uses when making the openai API call. You can easily replicate these results in Python using the provided code snippet.

It is worth noting that executing multiple calls of the last example seems to yield consistent results. However, resetting the code and executing it again may eventually lead to different outcomes.

In conclusion, GPT-4 exhibits non-deterministic behavior when accessed through LangChain ReAct with tool implementation in structured chats. This issue raises questions about understanding the underlying cause and determining possible solutions. We invite experts in the field to shed light on this topic and contribute to a better understanding of the problem and potential remedies.


1. What is LangChain ReAct?

LangChain ReAct is a structured chat agent that relies on the LangChain ReAct API for data collection, query processing, and retrieval of information.

2. What is GPT-4?

GPT-4 refers to the fourth iteration of the Generative Pre-trained Transformer (GPT) language model developed by OpenAI. It is known for its ability to generate human-like text responses.

3. What is non-deterministic behavior?

Non-deterministic behavior refers to the inconsistency in the output or behavior of a system, even when given the same input or set of conditions.

4. How can I reproduce the inconsistent responses described in this article?

By following the provided code example, you can recreate the scenarios that demonstrate the non-deterministic nature of GPT-4 responses when accessed through LangChain ReAct.

5. Are there any known solutions to address this issue?

At present, there are no known solutions to resolve the non-deterministic behavior of GPT-4 in the context of LangChain ReAct. Further research, analysis, and community collaboration may help in finding potential solutions.

Subscribe Google News Channel