[GH-ISSUE #11792] issue: System Prompt Does Not Trigger Function Calls (Function Calling Issue) #55025

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GiteaMirror · 2026-05-05T17:02:50-05:00

GiteaMirror commented

2026-05-05 17:02:50 -05:00

Originally created by @rifkisarici on GitHub (Mar 17, 2025).
Original GitHub issue: https://github.com/open-webui/open-webui/issues/11792

Check Existing Issues

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

Installation Method

Docker

Open WebUI Version

v0.5.20

Ollama Version (if applicable)

No response

Operating System

Windows 11

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 listed steps to reproduce the bug in detail.

Expected Behavior

When the system prompt contains the instruction:
The model must call the "check_system_status()" function when the user requests it.

Then the model should:

Detect "check_system_status" in the user message.
Call check_system_status() and return its output.
The final response should be:
[SYSTEM PROMPT TEST] System status: Active

Instead of just:
[SYSTEM PROMPT TEST] check_system_status()

Actual Behavior

The model generates a static response instead of calling the function.
It only returns [SYSTEM PROMPT TEST] check_system_status(), but does not actually execute check_system_status().-
We can only manually trigger function calling inside outlet() using if "check_system_status" in user_message:.

Steps to Reproduce

Set the system prompt with the instruction:
The model must call the check_system_status() function when the user requests it.
Run Open WebUI and send the following message:
check_system_status
Observe the response:
[SYSTEM PROMPT TEST] check_system_status()
The function check_system_status() is never actually executed.
However, adding manual handling inside outlet() like this works:

if "check_system_status" in user_message:
    function_result = self.check_system_status()
    body["messages"].append({"role": "assistant", "content": function_result})

Logs & Screenshots

📌 Code Example

To better illustrate the problem, here is the full code:

from pydantic import BaseModel, Field
from typing import Optional

class Filter:
    class Valves(BaseModel):
        priority: int = Field(
            default=0, description="Priority level for the filter operations."
        )
        max_turns: int = Field(
            default=8, description="Maximum allowable conversation turns for a user."
        )
        pass

    class UserValves(BaseModel):
        max_turns: int = Field(
            default=4, description="Maximum allowable conversation turns for a user."
        )
        pass

    def __init__(self):
        self.valves = self.Valves()
        print("📢 System prompt is running!")
        pass

    def check_system_status(self) -> str:
        """
        A simple test function. It should be executed when called by the system prompt.
        """
        print("✅ check_system_status() function executed!")
        return "System status: Active"

    def outlet(self, body: dict, __user__: Optional[dict] = None) -> dict:
        print("📢 outlet is running!")

        messages = body.get("messages", [])
        user_message = messages[-2].get("content", "") if len(messages) > 1 else ""

        if "check_system_status" in user_message:
            function_result = self.check_system_status()
            print(f"✅ Function Result: {function_result}")
            body["messages"].append({"role": "assistant", "content": function_result})

        return body

Relevant Logs:

📢 outlet is running!
💡 Assistant Message: [SYSTEM PROMPT TEST] check_system_status()
💡 User Message: check_system_status
✅ System prompt is running!
❌ Function was not executed!
✅ check_system_status() function should have been called, but it wasn't.

Additional Information

We were able to modify system prompt responses (e.g., adding [SYSTEM PROMPT TEST] at the beginning).
However, function calling does not work unless manually triggered inside outlet().
If Open WebUI does not support function calling, are there plans to implement this feature?

Originally created by @rifkisarici on GitHub (Mar 17, 2025). Original GitHub issue: https://github.com/open-webui/open-webui/issues/11792 ### Check Existing Issues - [x] I have searched the existing issues and discussions. - [x] I am using the latest version of Open WebUI. ### Installation Method Docker ### Open WebUI Version v0.5.20 ### Ollama Version (if applicable) _No response_ ### Operating System Windows 11 ### 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 listed steps to reproduce the bug in detail. ### Expected Behavior When the system prompt contains the instruction: `The model must call the "check_system_status()" function when the user requests it.` Then the model should: 1. Detect `"check_system_status"` in the user message. 2. Call `check_system_status() `and return its output. 3. The final response should be: `[SYSTEM PROMPT TEST] System status: Active` Instead of just: `[SYSTEM PROMPT TEST] check_system_status()` ### Actual Behavior - The model **generates a static response instead of calling the function.** - It only returns `[SYSTEM PROMPT TEST] check_system_status()`, but does not actually execute `check_system_status()`.- - **We can only manually trigger function calling inside `outlet()` using `if "check_system_status" in user_message:`.** ### Steps to Reproduce 1. Set the system prompt with the instruction: **The model must call the `check_system_status()` function when the user requests it.** 2. Run Open WebUI and send the following message: `check_system_status` 3. Observe the response: `[SYSTEM PROMPT TEST] check_system_status()` 4. The function `check_system_status()` is never actually executed. 5. However, adding manual handling inside `outlet()` like this works: ``` if "check_system_status" in user_message: function_result = self.check_system_status() body["messages"].append({"role": "assistant", "content": function_result}) ``` ### Logs & Screenshots ## 📌 Code Example To better illustrate the problem, here is the full code: ```python from pydantic import BaseModel, Field from typing import Optional class Filter: class Valves(BaseModel): priority: int = Field( default=0, description="Priority level for the filter operations." ) max_turns: int = Field( default=8, description="Maximum allowable conversation turns for a user." ) pass class UserValves(BaseModel): max_turns: int = Field( default=4, description="Maximum allowable conversation turns for a user." ) pass def __init__(self): self.valves = self.Valves() print("📢 System prompt is running!") pass def check_system_status(self) -> str: """ A simple test function. It should be executed when called by the system prompt. """ print("✅ check_system_status() function executed!") return "System status: Active" def outlet(self, body: dict, __user__: Optional[dict] = None) -> dict: print("📢 outlet is running!") messages = body.get("messages", []) user_message = messages[-2].get("content", "") if len(messages) > 1 else "" if "check_system_status" in user_message: function_result = self.check_system_status() print(f"✅ Function Result: {function_result}") body["messages"].append({"role": "assistant", "content": function_result}) return body ``` **Relevant Logs:** ``` 📢 outlet is running! 💡 Assistant Message: [SYSTEM PROMPT TEST] check_system_status() 💡 User Message: check_system_status ✅ System prompt is running! ❌ Function was not executed! ✅ check_system_status() function should have been called, but it wasn't. ``` ### Additional Information - **We were able to modify system prompt responses (e.g., adding `[SYSTEM PROMPT TEST] `at the beginning).** - **However, function calling does not work unless manually triggered inside `outlet()`.** - **If Open WebUI does not support function calling, are there plans to implement this feature?**

GiteaMirror added the bug label 2026-05-05 17:02:50 -05:00

GiteaMirror closed this issue

2026-05-05 17:02:51 -05:00

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Reference: github-starred/open-webui#55025