Bug: RAG Web Search fails with "cannot access local variable 'tool'"

[alexandrsuk]

Description

When using the RAG Web Search feature with a custom search engine (like SearXNG), the AI correctly identifies the intent to search and prepares the tool call parameters. However, before the tool call is dispatched, the Open WebUI backend crashes with an UnboundLocalError.

The SearXNG instance is working correctly and is accessible from the Open WebUI container. The error seems to be internal to the tool-calling logic in Open WebUI.

Steps to Reproduce

1. Configure Open WebUI to use SearXNG via RAG environment variables in docker-compose.yml:

   - RAG_WEB_SEARCH=True
   - RAG_WEB_SEARCH_ENGINE=searxng
   - RAG_SEARXNG_API_URL=http://searxng:8080/

2. In the chat, ask a question that requires a live web search (e.g., "What is the current temperature in Prague?").
3. The AI correctly prepares the search query.
4. The UI then displays the error: cannot access local variable 'tool' where it is not associated with a value.

Expected Behavior

The AI should successfully execute the call to the SearXNG API URL, receive the search results, and use them to formulate an answer.

Actual Behavior

The tool call fails with a Python UnboundLocalError originating from the Open WebUI backend. The search is never actually performed.

Screenshot of the error in the UI:
(Zde vložte ten screenshot, který jste poslal mně)

Environment Details

• Open WebUI Version: Using ghcr.io/open-webui/open-webui:latest tag.
• Model: gpt-oss:20b
• Setup: Running in Docker on Windows.
• Web Search Tool: Self-hosted searxng container.

Logs

Here is the relevant error message from the Open WebUI logs:

log-open-webui-001.txt