[GH-ISSUE #16992] issue: OpenWebUI is not passing required parameters to MCPO #56793

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opened 2026-05-05 20:07:03 -05:00 by GiteaMirror · 6 comments
Owner

Originally created by @hamza-56 on GitHub (Aug 28, 2025).
Original GitHub issue: https://github.com/open-webui/open-webui/issues/16992

Check Existing Issues

  • I have searched the existing issues and discussions.
  • I am using the latest version of Open WebUI.

Installation Method

Git Clone

Open WebUI Version

v0.6.25

Ollama Version (if applicable)

No response

Operating System

macOS

Browser (if applicable)

No response

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

OpenWebUI should ask user for required MCP parameters

Actual Behavior

OpenWebUI does not pass the required MCP tool parameters, causing a 500 error in MCPO.

Steps to Reproduce

  1. Set up a basic MCP server with an authentication tool that requires two parameters: username and password.
  2. Start the MCP server and run it through the MCPO proxy.
  3. Register the tool in OpenWebUI.
  4. Use OpenWebUI to call the tool and attempt authentication.
    Issue: OpenWebUI does not prompt for username and password, even though they are required parameters for the auth tool.

Logs & Screenshots

Image

Additional Information

No response

Originally created by @hamza-56 on GitHub (Aug 28, 2025). Original GitHub issue: https://github.com/open-webui/open-webui/issues/16992 ### Check Existing Issues - [x] I have searched the existing issues and discussions. - [x] I am using the latest version of Open WebUI. ### Installation Method Git Clone ### Open WebUI Version v0.6.25 ### Ollama Version (if applicable) _No response_ ### Operating System macOS ### Browser (if applicable) _No response_ ### 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 OpenWebUI should ask user for required MCP parameters ### Actual Behavior OpenWebUI does not pass the required MCP tool parameters, causing a 500 error in MCPO. ### Steps to Reproduce 1. Set up a basic MCP server with an authentication tool that requires two parameters: username and password. 3. Start the MCP server and run it through the MCPO proxy. 5. Register the tool in OpenWebUI. 7. Use OpenWebUI to call the tool and attempt authentication. **Issue:** OpenWebUI does not prompt for username and password, even though they are required parameters for the auth tool. ### Logs & Screenshots <img width="2282" height="1252" alt="Image" src="https://github.com/user-attachments/assets/0f30de31-1ffa-48ad-88bf-d3cda6732cde" /> ### Additional Information _No response_
GiteaMirror added the bug label 2026-05-05 20:07:03 -05:00
Author
Owner

@tjbck commented on GitHub (Aug 28, 2025):

You'll most likely have to specify the username and the password in the message content for the LLM to pick up the credentials.

Related #16940

<!-- gh-comment-id:3232900422 --> @tjbck commented on GitHub (Aug 28, 2025): You'll most likely have to specify the username and the password in the message content for the LLM to pick up the credentials. Related #16940
Author
Owner

@savantskie commented on GitHub (Aug 28, 2025):

Or you could place it in the system prompt too

<!-- gh-comment-id:3234053284 --> @savantskie commented on GitHub (Aug 28, 2025): Or you could place it in the system prompt too
Author
Owner

@jsweetzer-ea commented on GitHub (Aug 28, 2025):

You'll most likely have to specify the username and the password in the message content for the LLM to pick up the credentials.

Related #16940

Pass credentials in plain text via the LLM message to the MCP server? That is not a good idea.

https://github.com/open-webui/open-webui/pull/16651

The major drawback for Open WebUI atm is its handling of authenticated MCP, via MCPO which is now significantly behind the current spec and could not handle OAuth for 1st party MCP server support.

We will fork and merge the community PR but I would urge you to re-consider the stance on MCP + tools via MCPO.

<!-- gh-comment-id:3234078134 --> @jsweetzer-ea commented on GitHub (Aug 28, 2025): > You'll most likely have to specify the username and the password in the message content for the LLM to pick up the credentials. > > Related [#16940](https://github.com/open-webui/open-webui/issues/16940) Pass credentials in plain text via the LLM message to the MCP server? That is not a good idea. https://github.com/open-webui/open-webui/pull/16651 The major drawback for Open WebUI atm is its handling of authenticated MCP, via MCPO which is now significantly behind the current spec and could not handle OAuth for 1st party MCP server support. We will fork and merge the community PR but I would urge you to re-consider the stance on MCP + tools via MCPO.
Author
Owner

@tjbck commented on GitHub (Aug 28, 2025):

@jsweetzer-ea please search for the existing issues first https://github.com/open-webui/open-webui/issues/15932

<!-- gh-comment-id:3234085154 --> @tjbck commented on GitHub (Aug 28, 2025): @jsweetzer-ea please search for the existing issues first https://github.com/open-webui/open-webui/issues/15932
Author
Owner

@jsweetzer-ea commented on GitHub (Aug 28, 2025):

Thanks @tjbck - I'd seen that.

Are you able to share more details on how you plan to integrate MCP support in the main project? Any target dates (to help assess the cost:effort of forking in meantime)? I would have commented there but it is locked.

<!-- gh-comment-id:3234135785 --> @jsweetzer-ea commented on GitHub (Aug 28, 2025): Thanks @tjbck - I'd seen that. Are you able to share more details on how you plan to integrate MCP support in the main project? Any target dates (to help assess the cost:effort of forking in meantime)? I would have commented there but it is locked.
Author
Owner

@tjbck commented on GitHub (Aug 28, 2025):

@jsweetzer-ea your current attitude does not help, we appreciate your patience.

<!-- gh-comment-id:3234153261 --> @tjbck commented on GitHub (Aug 28, 2025): @jsweetzer-ea your current attitude does not help, we appreciate your patience.
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Reference: github-starred/open-webui#56793