Action functions can now return HTMLResponse objects or (html, headers) tuples with Content-Disposition: inline to render rich UI iframes in chat, matching the existing tool behavior.
Why?
Actions and Tools are extremely similar - the only difference is who activates them
Tools get activated by LLMs
Actions get activated by Humans
Otherwise they behave the same. They get called on-demand and do something
So they should have the same capabilities and abilities for developers.
If you want to display beautiful graphs and charts with Actions, you have to inject a codeblock with the HTML content into the assistant's message by modifying the body - and even then it is only shown as an Artifact and not as a rich UI embed like the tools have available.
How action authors can now use Rich UI
Option A — HTMLResponse:
from fastapi.responses import HTMLResponse
async def action(self, body, __event_emitter__=None):
html = "<html><body><h1>Dashboard</h1></body></html>"
return HTMLResponse(content=html, headers={"Content-Disposition": "inline"})
No frontend changes were needed — the socket handler at Chat.svelte:416 already receives "embeds" events generically and renders them via FullHeightIframe.
Contributor License Agreement
By submitting this pull request, I confirm that I have read and fully agree to the Contributor License Agreement (CLA), and I am providing my contributions under its terms.
Note
Deleting the CLA section will lead to immediate closure of your PR and it will not be merged in.
🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.
## 📋 Pull Request Information
**Original PR:** https://github.com/open-webui/open-webui/pull/21294
**Author:** [@Classic298](https://github.com/Classic298)
**Created:** 2/10/2026
**Status:** ✅ Merged
**Merged:** 2/11/2026
**Merged by:** [@tjbck](https://github.com/tjbck)
**Base:** `dev` ← **Head:** `claude/verify-dynamic-ui-support-RDHW2`
---
### 📝 Commits (1)
- [`0a08d88`](https://github.com/open-webui/open-webui/commit/0a08d88d8af2c43c2268c49277d80878e8d20a88) Enable Rich UI embed support for action functions
### 📊 Changes
**2 files changed** (+25 additions, -1 deletions)
<details>
<summary>View changed files</summary>
📝 `backend/open_webui/utils/chat.py` (+24 -0)
📝 `backend/open_webui/utils/middleware.py` (+1 -1)
</details>
### 📄 Description
Action functions can now return HTMLResponse objects or (html, headers) tuples with Content-Disposition: inline to render rich UI iframes in chat, matching the existing tool behavior.
# Why?
<ins>**Actions and Tools are extremely similar - the only difference is who activates them**</ins>
Tools get activated by LLMs
Actions get activated by Humans
Otherwise they behave the same. They get called on-demand and do something
So they should have the same capabilities and abilities for developers.
If you want to display beautiful graphs and charts with Actions, you have to inject a codeblock with the HTML content into the assistant's message by modifying the body - and even then it is only shown as an Artifact and not as a rich UI embed like the tools have available.
---
How action authors can now use Rich UI
Option A — HTMLResponse:
```
from fastapi.responses import HTMLResponse
async def action(self, body, __event_emitter__=None):
html = "<html><body><h1>Dashboard</h1></body></html>"
return HTMLResponse(content=html, headers={"Content-Disposition": "inline"})
```
Option B — Tuple with headers:
```
async def action(self, body, __event_emitter__=None):
html = "<h1>Interactive Chart</h1><script>...</script>"
return (html, {"Content-Disposition": "inline", "Content-Type": "text/html"})
```
No frontend changes were needed — the socket handler at Chat.svelte:416 already receives "embeds" events generically and renders them via FullHeightIframe.
### Contributor License Agreement
By submitting this pull request, I confirm that I have read and fully agree to the [Contributor License Agreement (CLA)](https://github.com/open-webui/open-webui/blob/main/CONTRIBUTOR_LICENSE_AGREEMENT), and I am providing my contributions under its terms.
> [!NOTE]
> Deleting the CLA section will lead to immediate closure of your PR and it will not be merged in.
---
<sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>
Blocking a user prevents them from interacting with repositories, such as opening or commenting on pull requests or issues. Learn more about blocking a user.
📋 Pull Request Information
Original PR: https://github.com/open-webui/open-webui/pull/21294
Author: @Classic298
Created: 2/10/2026
Status: ✅ Merged
Merged: 2/11/2026
Merged by: @tjbck
Base:
dev← Head:claude/verify-dynamic-ui-support-RDHW2📝 Commits (1)
0a08d88Enable Rich UI embed support for action functions📊 Changes
2 files changed (+25 additions, -1 deletions)
View changed files
📝
backend/open_webui/utils/chat.py(+24 -0)📝
backend/open_webui/utils/middleware.py(+1 -1)📄 Description
Action functions can now return HTMLResponse objects or (html, headers) tuples with Content-Disposition: inline to render rich UI iframes in chat, matching the existing tool behavior.
Why?
Actions and Tools are extremely similar - the only difference is who activates them
Tools get activated by LLMs
Actions get activated by Humans
Otherwise they behave the same. They get called on-demand and do something
So they should have the same capabilities and abilities for developers.
If you want to display beautiful graphs and charts with Actions, you have to inject a codeblock with the HTML content into the assistant's message by modifying the body - and even then it is only shown as an Artifact and not as a rich UI embed like the tools have available.
How action authors can now use Rich UI
Option A — HTMLResponse:
Option B — Tuple with headers:
No frontend changes were needed — the socket handler at Chat.svelte:416 already receives "embeds" events generically and renders them via FullHeightIframe.
Contributor License Agreement
By submitting this pull request, I confirm that I have read and fully agree to the Contributor License Agreement (CLA), and I am providing my contributions under its terms.
🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.