[GH-ISSUE #1747] Stop Sequence with Backslash '\' Does Not Work #12624

New Issue

GiteaMirror · 2026-04-19T19:33:03-05:00

GiteaMirror commented

2026-04-19 19:33:03 -05:00

Originally created by @ibndias on GitHub (Apr 25, 2024).
Original GitHub issue: https://github.com/open-webui/open-webui/issues/1747

Bug Report

Stop Sequence with Backslash '' Does Not Work

Description

It seems there is a post process that escape the backslash character. So the final stop sequence produces is incorrect.

Bug Summary:
It seems there is a post process that escape the backslash character. So the final stop sequence produces is incorrect.

Steps to Reproduce:
I am using VLLM Backend.
Open any model, and set stop token on every line break, example set: \n

Expected Behavior:
Stop token should be stay \n instead of becoming \\n

Actual Behavior:
The stop token shown in my inspection is escaped and added another backslash prefix.

Environment

Open WebUI Version: v0.1.121
Ollama Version 0.1.32
Operating System: POP OS 22.04]
Browser (if applicable): Chrome Version 123.0.6312.105 (Official Build) (64-bit)

Reproduction Details

I am using VLLM Backend.
Open any model, and set stop token on every line break, example set: \n

Confirmation:

I have read and followed all the instructions provided in the README.md.
I am on the latest version of both Open WebUI and Ollama.
I have included the browser console logs.
I have included the Docker container logs.

Logs and Screenshots

As we can see the system prompt has no problem handling line break into \n

But the stop sequence becomes \\n instead of just \n

Installation Method

Docker Method

Originally created by @ibndias on GitHub (Apr 25, 2024). Original GitHub issue: https://github.com/open-webui/open-webui/issues/1747 # Bug Report Stop Sequence with Backslash '\' Does Not Work ## Description It seems there is a post process that escape the backslash character. So the final stop sequence produces is incorrect. **Bug Summary:** It seems there is a post process that escape the backslash character. So the final stop sequence produces is incorrect. **Steps to Reproduce:** I am using VLLM Backend. Open any model, and set stop token on every line break, example set: `\n` **Expected Behavior:** Stop token should be stay `\n` instead of becoming `\\n` **Actual Behavior:** The stop token shown in my inspection is escaped and added another backslash prefix. ## Environment - **Open WebUI Version:** v0.1.121 Ollama Version 0.1.32 - **Operating System:** POP OS 22.04] - **Browser (if applicable):** Chrome Version 123.0.6312.105 (Official Build) (64-bit) ## Reproduction Details I am using VLLM Backend. Open any model, and set stop token on every line break, example set: `\n` **Confirmation:** - [x] I have read and followed all the instructions provided in the README.md. - [x] I am on the latest version of both Open WebUI and Ollama. - [x] I have included the browser console logs. - [ ] I have included the Docker container logs. ## Logs and Screenshots ![image](https://github.com/open-webui/open-webui/assets/3958152/9fd1f5e1-2c5b-40cd-9539-a1c86a8c17c4) As we can see the system prompt has no problem handling line break into `\n` But the stop sequence becomes `\\n` instead of just `\n` ## Installation Method Docker Method

GiteaMirror closed this issue

2026-04-19 19:33:05 -05:00

GiteaMirror commented

2026-04-19 19:33:07 -05:00

@tjbck commented on GitHub (Apr 27, 2024):

Taking a look!

@tjbck commented on GitHub (Apr 27, 2024): Taking a look!

GiteaMirror commented

2026-04-19 19:33:07 -05:00

@tjbck commented on GitHub (Apr 28, 2024):

Should be fixed on our dev branch, let me know if the issue persists!

@tjbck commented on GitHub (Apr 28, 2024): Should be fixed on our dev branch, let me know if the issue persists!