github-starred/open-webui
2
0
Fork 0
mirror of https://github.com/open-webui/open-webui.git synced 2026-05-07 03:18:23 -05:00
Code Issues 1.3k Packages Projects Releases 126 Wiki Activity

[GH-ISSUE #19500] issue: 'list' object has no attribute 'split' error when using OpenAPI tool server (MCPO) #34432

New Issue
Closed
opened 2026-04-25 08:25:42 -05:00 by GiteaMirror · 1 comment
GiteaMirror commented 2026-04-25 08:25:42 -05:00
Owner
Copy Link

Originally created by @nullEFFORT on GitHub (Nov 26, 2025).
Original GitHub issue: https://github.com/open-webui/open-webui/issues/19500

Check Existing Issues

  • I have searched for any existing and/or related issues.
  • I have searched for any existing and/or related discussions.
  • I have also searched in the CLOSED issues AND CLOSED discussions and found no related items (your issue might already be addressed on the development branch!).
  • I am using the latest version of Open WebUI.

Installation Method

Docker

Open WebUI Version

0.6.40

Ollama Version (if applicable)

No response

Operating System

Unraid 6.12.24

Browser (if applicable)

Chrome

Confirmation

  • I have read and followed all instructions in README.md.
  • I am using the latest version of both Open WebUI and Ollama.
  • I have included the browser console logs.
  • I have included the Docker container logs.
  • I have provided every relevant configuration, setting, and environment variable used in my setup.
  • I have clearly listed every relevant configuration, custom setting, environment variable, and command-line option that influences my setup (such as Docker Compose overrides, .env values, browser settings, authentication configurations, etc).
  • I have documented step-by-step reproduction instructions that are precise, sequential, and leave nothing to interpretation. My steps:
  • Start with the initial platform/version/OS and dependencies used,
  • Specify exact install/launch/configure commands,
  • List URLs visited, user input (incl. example values/emails/passwords if needed),
  • Describe all options and toggles enabled or changed,
  • Include any files or environmental changes,
  • Identify the expected and actual result at each stage,
  • Ensure any reasonably skilled user can follow and hit the same issue.

Expected Behavior

Tool should execute and return results to the model.

Actual Behavior

When using an OpenAPI tool server configured via MCPO (MCP-to-OpenAPI proxy), invoking any tool results in the error:

'list' object has no attribute 'split'

The error appears in the chat UI when the model attempts to call a tool. The tool connection tests as "successful" in
the tool server configuration.

Steps to Reproduce

  1. Set up MCPO proxy (ghcr.io/open-webui/mcpo:main) connected to an MCP server (google_workspace_mcp)
  2. Add OpenAPI tool server in Open-WebUI Settings → Tools with URL: http://:8080/google-workspace
  3. Enable the tool in a chat
  4. Ask the model to use the tool (e.g., "list my calendars")
  5. Error appears: 'list' object has no attribute 'split'

Logs & Screenshots

The MCPO backend works correctly when called directly via curl:
curl -X POST "http://192.168.1.6:8080/google-workspace/list_calendars"
-H "Content-Type: application/json"
-d '{"user_google_email":"user@example.com"}'

Returns: "Successfully listed 2 calendars..."

No Python traceback appears in Open-WebUI logs for this specific error - it only appears in the UI.

Additional Information

Environment details:

  • MCPO: ghcr.io/open-webui/mcpo:main
  • MCP Server: google_workspace_mcp v1.12.4
  • OpenAPI spec version: 3.1.0
  • Model: gpt-5.1-chat-latest (OpenAI API)
  • Tool server type: OpenAPI
  • Tool visibility: Private
Originally created by @nullEFFORT on GitHub (Nov 26, 2025). Original GitHub issue: https://github.com/open-webui/open-webui/issues/19500 ### Check Existing Issues - [x] I have searched for any existing and/or related issues. - [x] I have searched for any existing and/or related discussions. - [x] I have also searched in the CLOSED issues AND CLOSED discussions and found no related items (your issue might already be addressed on the development branch!). - [x] I am using the latest version of Open WebUI. ### Installation Method Docker ### Open WebUI Version 0.6.40 ### Ollama Version (if applicable) _No response_ ### Operating System Unraid 6.12.24 ### Browser (if applicable) Chrome ### Confirmation - [x] I have read and followed all instructions in `README.md`. - [x] I am using the latest version of **both** Open WebUI and Ollama. - [x] I have included the browser console logs. - [x] I have included the Docker container logs. - [x] I have **provided every relevant configuration, setting, and environment variable used in my setup.** - [x] I have clearly **listed every relevant configuration, custom setting, environment variable, and command-line option that influences my setup** (such as Docker Compose overrides, .env values, browser settings, authentication configurations, etc). - [x] I have documented **step-by-step reproduction instructions that are precise, sequential, and leave nothing to interpretation**. My steps: - Start with the initial platform/version/OS and dependencies used, - Specify exact install/launch/configure commands, - List URLs visited, user input (incl. example values/emails/passwords if needed), - Describe all options and toggles enabled or changed, - Include any files or environmental changes, - Identify the expected and actual result at each stage, - Ensure any reasonably skilled user can follow and hit the same issue. ### Expected Behavior Tool should execute and return results to the model. ### Actual Behavior When using an OpenAPI tool server configured via MCPO (MCP-to-OpenAPI proxy), invoking any tool results in the error: 'list' object has no attribute 'split' The error appears in the chat UI when the model attempts to call a tool. The tool connection tests as "successful" in the tool server configuration. ### Steps to Reproduce 1. Set up MCPO proxy (ghcr.io/open-webui/mcpo:main) connected to an MCP server (google_workspace_mcp) 2. Add OpenAPI tool server in Open-WebUI Settings → Tools with URL: http://<mcpo-ip>:8080/google-workspace 3. Enable the tool in a chat 4. Ask the model to use the tool (e.g., "list my calendars") 5. Error appears: 'list' object has no attribute 'split' ### Logs & Screenshots The MCPO backend works correctly when called directly via curl: curl -X POST "http://192.168.1.6:8080/google-workspace/list_calendars" \ -H "Content-Type: application/json" \ -d '{"user_google_email":"user@example.com"}' # Returns: "Successfully listed 2 calendars..." No Python traceback appears in Open-WebUI logs for this specific error - it only appears in the UI. ### Additional Information Environment details: - MCPO: ghcr.io/open-webui/mcpo:main - MCP Server: google_workspace_mcp v1.12.4 - OpenAPI spec version: 3.1.0 - Model: gpt-5.1-chat-latest (OpenAI API) - Tool server type: OpenAPI - Tool visibility: Private
GiteaMirror added the bug label 2026-04-25 08:25:42 -05:00
GiteaMirror commented 2026-04-25 08:25:44 -05:00
Author
Owner
Copy Link

@silentoplayz commented on GitHub (Nov 26, 2025):

Literally check for open issues. https://github.com/open-webui/open-webui/issues/19486

Image Image
<!-- gh-comment-id:3579092726 --> @silentoplayz commented on GitHub (Nov 26, 2025): Literally check for open issues. https://github.com/open-webui/open-webui/issues/19486 <img width="1244" height="294" alt="Image" src="https://github.com/user-attachments/assets/f35177b6-54dc-4229-96ee-d629cadab502" /> <img width="921" height="224" alt="Image" src="https://github.com/user-attachments/assets/77d3b79f-2b79-4612-bfb8-d0f1a3e73e84" />
Sign in to join this conversation.
No Branch/Tag Specified
Branches Tags
Labels
Clear labels
bug
confirmed
confirmed issue
core
documentation
enhancement
good first issue
help wanted
non-core
pull-request
Mirrored from GitHub Pull Request
 python
question
testing wanted
No Label bug
Milestone
No items
No Milestone
Projects
Clear projects
No project
Assignees
Clear assignees
GiteaMirror ninjasurge
No Assignees
1 Participants
Notifications
Due Date
No due date set.
Dependencies

No dependencies set.

Reference: github-starred/open-webui#34432
Delete Branch "%!s()"

Deleting a branch is permanent. Although the deleted branch may continue to exist for a short time before it actually gets removed, it CANNOT be undone in most cases. Continue?