[GH-ISSUE #20207] issue: Infinite loading screen when MCP tool is enabled. #57790

New Issue

2026-05-05T21:37:04-05:00

GiteaMirror commented

2026-05-05 21:37:04 -05:00

Originally created by @ppeterka on GitHub (Dec 27, 2025).
Original GitHub issue: https://github.com/open-webui/open-webui/issues/20207

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

0.6.42, 0.6.43

Ollama Version (if applicable)

N/A

Operating System

N/A

Browser (if applicable)

N/A

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

Opening the URL, frontend should load.

Actual Behavior

Only sidebar loads, loading animation stays in place, error in browser console:

Steps to Reproduce

Log in to Open WebUI, create an External Tool connection, like this:

Save it, enable it.

---> Frontend still works at this point flawlessly!

Hit Ctrl-F5 in browser, frontend stuck in loading state, with error on console:

Use Settings to disable the External tool:

Hit Ctrl-F5 again - frontend works correctly again.

Logs & Screenshots

Open WebUI JS error when External tool MCP definition active:

Uncaught (in promise) TypeError: Cannot convert undefined or null to object
    at Object.entries (<anonymous>)
    at d1 (index.ts:1253:39)
    at index.ts:388:15
    at Array.map (<anonymous>)
    at Ss (index.ts:349:6)
    at Q (+layout.svelte:119:31)
    at +layout.svelte:159:37
    at te (+layout.svelte:105:10)
    at async Promise.all (:3000/index 3)
    at async +layout.svelte:154:9

Frontend in permanent loading state:

Additional Information

Tested in 0.6.42 and 0.6.43 too.

Frontend does work if the External tools are not enabled when the browser starts the session, and stuff breaks with a Ctrl-F5.

Originally created by @ppeterka on GitHub (Dec 27, 2025). Original GitHub issue: https://github.com/open-webui/open-webui/issues/20207 ### 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 0.6.42, 0.6.43 ### Ollama Version (if applicable) N/A ### Operating System N/A ### Browser (if applicable) N/A ### 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 Opening the URL, frontend should load. ### Actual Behavior Only sidebar loads, loading animation stays in place, error in browser console: ### Steps to Reproduce Log in to Open WebUI, create an External Tool connection, like this: <img width="826" height="587" alt="Image" src="https://github.com/user-attachments/assets/ef91a103-7591-4da5-bfc6-7bc0aadf0468" /> Save it, enable it. ---> Frontend still works at this point flawlessly! Hit Ctrl-F5 in browser, frontend stuck in loading state, with error on console: <img width="859" height="590" alt="Image" src="https://github.com/user-attachments/assets/787466c4-eadc-4484-85a8-2888076ec9f4" /> Use Settings to disable the External tool: <img width="770" height="536" alt="Image" src="https://github.com/user-attachments/assets/36529e91-eaca-4966-acf1-e92eb0db752a" /> Hit Ctrl-F5 again - frontend works correctly again. ### Logs & Screenshots **Open WebUI JS error when External tool MCP definition active:** ``` Uncaught (in promise) TypeError: Cannot convert undefined or null to object at Object.entries (<anonymous>) at d1 (index.ts:1253:39) at index.ts:388:15 at Array.map (<anonymous>) at Ss (index.ts:349:6) at Q (+layout.svelte:119:31) at +layout.svelte:159:37 at te (+layout.svelte:105:10) at async Promise.all (:3000/index 3) at async +layout.svelte:154:9 ``` Frontend in permanent loading state: <img width="859" height="590" alt="Image" src="https://github.com/user-attachments/assets/43c13715-a3fc-4f94-a8b9-cab2c19981d0" /> ### Additional Information Tested in 0.6.42 and 0.6.43 too. Frontend does work if the External tools are not enabled when the browser starts the session, and stuff breaks with a Ctrl-F5.

GiteaMirror added the bug label 2026-05-05 21:37:04 -05:00

GiteaMirror closed this issue

2026-05-05 21:37:04 -05:00

GiteaMirror commented

2026-05-05 21:37:05 -05:00

@owui-terminator[bot] commented on GitHub (Dec 27, 2025):

🔍 Similar Issues Found

I found some existing issues that might be related to this one. Please check if any of these are duplicates or contain helpful solutions:

#19864 issue:
by Haervwe • Dec 10, 2025 • bug
#20019 issue:
by j63440490 • Dec 17, 2025 • bug
#19813 issue: Failed to connect to MCP server, while the connection test works fine
by spi-dlp • Dec 08, 2025 • bug
#19777 issue:
by Yaute7 • Dec 05, 2025 • bug
#20092 issue:
by VideoRyan • Dec 22, 2025 • bug

Show 5 more related issues

#20046 issue:
by pierrelouisbescond • Dec 19, 2025 • bug
#19438 issue: Icon loading regression
by JoelShepard • Nov 24, 2025 • bug
#19563 issue:
by naruto7g • Nov 28, 2025 • bug
#18981 issue: 0.6.35 error using tools through mcpo
by GlisseManTV • Nov 06, 2025 • bug
#15730 issue: Broken network connection to MCP tool causes endloss GUI loading
by FelHell • Jul 15, 2025 • bug

💡 Tips:

If this is a duplicate, please consider closing this issue and adding any additional details to the existing one
If you found a solution in any of these issues, please share it here to help others

This comment was generated automatically by a bot. Please react with a 👍 if this comment was helpful, or a 👎 if it was not.

@owui-terminator[bot] commented on GitHub (Dec 27, 2025): 🔍 **Similar Issues Found** I found some existing issues that might be related to this one. Please check if any of these are duplicates or contain helpful solutions: 1. [#19864](https://github.com/open-webui/open-webui/issues/19864) **issue:** *by Haervwe • Dec 10, 2025 • `bug`* 2. [#20019](https://github.com/open-webui/open-webui/issues/20019) **issue:** *by j63440490 • Dec 17, 2025 • `bug`* 3. [#19813](https://github.com/open-webui/open-webui/issues/19813) **issue: Failed to connect to MCP server, while the connection test works fine** *by spi-dlp • Dec 08, 2025 • `bug`* 4. [#19777](https://github.com/open-webui/open-webui/issues/19777) **issue:** *by Yaute7 • Dec 05, 2025 • `bug`* 5. [#20092](https://github.com/open-webui/open-webui/issues/20092) **issue:** *by VideoRyan • Dec 22, 2025 • `bug`* <details> <summary>Show 5 more related issues</summary> 6. [#20046](https://github.com/open-webui/open-webui/issues/20046) **issue:** *by pierrelouisbescond • Dec 19, 2025 • `bug`* 7. [#19438](https://github.com/open-webui/open-webui/issues/19438) **issue: Icon loading regression** *by JoelShepard • Nov 24, 2025 • `bug`* 8. [#19563](https://github.com/open-webui/open-webui/issues/19563) **issue:** *by naruto7g • Nov 28, 2025 • `bug`* 9. [#18981](https://github.com/open-webui/open-webui/issues/18981) **issue: 0.6.35 error using tools through mcpo** *by GlisseManTV • Nov 06, 2025 • `bug`* 10. [#15730](https://github.com/open-webui/open-webui/issues/15730) **issue: Broken network connection to MCP tool causes endloss GUI loading** *by FelHell • Jul 15, 2025 • `bug`* </details> --- 💡 **Tips:** - If this is a duplicate, please consider closing this issue and adding any additional details to the existing one - If you found a solution in any of these issues, please share it here to help others *This comment was generated automatically by a bot.* Please react with a 👍 if this comment was helpful, or a 👎 if it was not.

GiteaMirror commented

2026-05-05 21:37:06 -05:00

@rgaricano commented on GitHub (Dec 27, 2025):

The error occurs because the frontend code expects an OpenAPI-style configuration but receives an MCP-style configuration, causing Object.entries() to be called on an undefined value during tool server initialization.

Your JSON format uses mcpServers structure, but the code expects an OpenAPI-style configuration with properties like url, spec_type, etc.

Your MCP configuration:

{  
 "mcpServers":{  
  "searxng":{  
   "url":"http://192.168.2.10:12346/sse"  
  }  
 }  
}

But the code expects this format (for OpenAPI):

{  
  "url": "http://192.168.2.10:12346/sse",  
  "spec_type": "url",  
  "path": "/openapi.json"  
}

To solve:

use the OpenAPI format instead (as indicated before)
Or use MCP type correctly (Click the type toggle button to switch from "OpenAPI" to "MCP" when adding the connection)

@rgaricano commented on GitHub (Dec 27, 2025): The error occurs because the frontend code expects an OpenAPI-style configuration but receives an MCP-style configuration, causing Object.entries() to be called on an undefined value during tool server initialization. Your JSON format uses mcpServers structure, but the code expects an OpenAPI-style configuration with properties like url, spec_type, etc. Your MCP configuration: ``` { "mcpServers":{ "searxng":{ "url":"http://192.168.2.10:12346/sse" } } } ``` But the code expects this format (for OpenAPI): ``` { "url": "http://192.168.2.10:12346/sse", "spec_type": "url", "path": "/openapi.json" } ``` To solve: - use the OpenAPI format instead (as indicated before) - Or use MCP type correctly (Click the type toggle button to switch from "OpenAPI" to "MCP" when adding the connection)

GiteaMirror commented

2026-05-05 21:37:07 -05:00

@ppeterka commented on GitHub (Dec 27, 2025):

Yep, you're right - but I believe whatever I put in there, should be properly sanitized and should not break the UI itself...

@ppeterka commented on GitHub (Dec 27, 2025): Yep, you're right - but I believe whatever I put in there, should be properly sanitized and should not break the UI itself...

GiteaMirror commented

2026-05-05 21:37:08 -05:00