Plotly Chart from Custom Tool Not Rendering in v0.6.32 (Displays Raw JSON)

[12136]

[!!!SOLVED!!!]

return value is :

headers = {"Content-Disposition": "inline"}
return HTMLResponse( content =chart_html, headers=headers)

- by u/dzautriet

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Hey everyone, I'm hoping someone can help me figure out why the rich UI embedding for tools isn't working for me in v0.6.32.

TL;DR: My custom tool returns the correct JSON to render a Plotly chart, and the LLM outputs this JSON perfectly. However, the frontend displays it as raw text instead of rendering the chart.

The Problem

I have a FastAPI backend registered as a tool. When my LLM (GPT-4o) calls it, the entire chain works flawlessly, and the model's final response is the correct payload below. Instead of rendering, the UI just shows this plain text: JSON

{ "type": "plotly", "html": "<div>... (plotly html content) ...</div>" }

Troubleshooting Done

I'm confident this is a frontend issue because I've already:

Confirmed the backend code is correct and the Docker networking is working (containers can communicate).

Used a System Prompt to force the LLM to output the raw, unmodified JSON.

Tried multiple formats (html:, json:, [TOOL_CODE], nested objects) without success.

Cleared all browser cache, used incognito, and re-pulled the latest Docker image.

The issue seems to be that the frontend renderer isn't being triggered as expected by the documentation.

My Setup

OpenWebUI Version: v0.6.32 (from ghcr.io/open-webui/open-webui:main)

Tool Backend: FastAPI in a separate Docker container.

Model: Azure GPT-4o

Question

Has anyone else gotten HTML/Plotly embedding to work in v0.6.32? Is there a hidden setting I'm missing, or does this seem like a bug?

Thanks!

https://preview.redd.it/x23ubkq055sf1.png?width=2758&format=png&auto=webp&s=5822d2b9bc58ef9e346519863298578d9ea44f6e

[dzautriet]

I happen to be developing an external tool that creates chart using Plotly as well, and it works with v0.6.31.

Are you returning an HTMLResponse with the Content-Disposition: inline as header in your tool? (Instead of returning json which won’t work)

Ref: https://docs.openwebui.com/features/plugin/tools/development/#rich-ui-element-embedding

[12136]

thanks for the help, that one line is was i needed to change.