[GH-ISSUE #20991] issue: Empty embeds attribute renders as {} in tool calls UI #34882

New Issue

GiteaMirror · 2026-04-25T09:03:42-05:00

GiteaMirror commented

2026-04-25 09:03:42 -05:00

Originally created by @cannontrodder on GitHub (Jan 28, 2026).
Original GitHub issue: https://github.com/open-webui/open-webui/issues/20991

Check Existing Issues

I have searched for any existing and/or related issues.
I have searched for any existing and/or related discussions.
I have also searched in the CLOSED issues AND CLOSED discussions and found no related items.
I am using the latest version of Open WebUI.

Installation Method

Docker

Open WebUI Version

v0.7.2

Ollama Version (if applicable)

N/A (using AWS Bedrock via LiteLLM)

Operating System

Kubernetes (Linux containers)

Browser (if applicable)

Chrome, Safari

Confirmation

I have read and followed all instructions in README.md.
I am using the latest version of Open WebUI.
I have included the browser console logs.
I have included relevant code analysis.
I have provided every relevant configuration, setting, and environment variable used in my setup.
I have documented step-by-step reproduction instructions that are precise, sequential, and leave nothing to interpretation.

Expected Behavior

When a tool call completes without any embeds (e.g., image generation tools), the UI should cleanly display the tool result without any spurious rendered content.

Actual Behavior

An empty object {} is rendered in a red box in the UI after tool calls that don't return embeds. The browser console shows:

SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data

Root Cause Analysis

In backend/open_webui/utils/middleware.py at line 2388:

tool_result_embeds = result.get("embeds", "")
tool_calls_display_content = f'...embeds="{html.escape(json.dumps(tool_result_embeds))}"...'

When embeds is missing from the result:

Default value is "" (empty string)
json.dumps("") → '""'
html.escape('""') → '""'
HTML attribute becomes embeds=""""

In the frontend (Collapsible.svelte line 96):

{@const embeds = parseJSONString(decode(attributes?.embeds ?? ''))}

decode('""') → ""
JSON.parse('""') → "" (empty string, not array)
The check if embeds && Array.isArray(embeds) fails
Empty string gets rendered as {}

Steps to Reproduce

Use any tool that doesn't return embeds (e.g., built-in image generation)
Send a prompt like "Generate an image of a cat"
Wait for the tool to execute
Observe {} rendered in the UI and JSON parse error in console

Proposed Fix

# Change default from "" to []
tool_result_embeds = result.get("embeds", [])

# Only include embeds attribute when non-empty
embeds_attr = f' embeds="{html.escape(json.dumps(tool_result_embeds))}"' if tool_result_embeds else ''

I have a PR ready with this fix.

Logs & Screenshots

Browser console error:

SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data

Stored message content showing the problematic attribute:

<details type="tool_calls" ... embeds="&quot;&quot;">

Originally created by @cannontrodder on GitHub (Jan 28, 2026). Original GitHub issue: https://github.com/open-webui/open-webui/issues/20991 ### Check Existing Issues - [x] I have searched for any existing and/or related issues. - [x] I have searched for any existing and/or related discussions. - [x] I have also searched in the CLOSED issues AND CLOSED discussions and found no related items. - [x] I am using the latest version of Open WebUI. ### Installation Method Docker ### Open WebUI Version v0.7.2 ### Ollama Version (if applicable) N/A (using AWS Bedrock via LiteLLM) ### Operating System Kubernetes (Linux containers) ### Browser (if applicable) Chrome, Safari ### Confirmation - [x] I have read and followed all instructions in `README.md`. - [x] I am using the latest version of Open WebUI. - [x] I have included the browser console logs. - [x] I have included relevant code analysis. - [x] I have **provided every relevant configuration, setting, and environment variable used in my setup.** - [x] I have documented **step-by-step reproduction instructions that are precise, sequential, and leave nothing to interpretation**. ### Expected Behavior When a tool call completes without any embeds (e.g., image generation tools), the UI should cleanly display the tool result without any spurious rendered content. ### Actual Behavior An empty object `{}` is rendered in a red box in the UI after tool calls that don't return embeds. The browser console shows: ``` SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data ``` ### Root Cause Analysis In `backend/open_webui/utils/middleware.py` at line 2388: ```python tool_result_embeds = result.get("embeds", "") tool_calls_display_content = f'...embeds="{html.escape(json.dumps(tool_result_embeds))}"...' ``` When `embeds` is missing from the result: 1. Default value is `""` (empty string) 2. `json.dumps("")` → `'""'` 3. `html.escape('""')` → `'""'` 4. HTML attribute becomes `embeds=""""` In the frontend (`Collapsible.svelte` line 96): ```javascript {@const embeds = parseJSONString(decode(attributes?.embeds ?? ''))} ``` 1. `decode('""')` → `""` 2. `JSON.parse('""')` → `""` (empty string, not array) 3. The check `if embeds && Array.isArray(embeds)` fails 4. Empty string gets rendered as `{}` ### Steps to Reproduce 1. Use any tool that doesn't return embeds (e.g., built-in image generation) 2. Send a prompt like "Generate an image of a cat" 3. Wait for the tool to execute 4. Observe `{}` rendered in the UI and JSON parse error in console ### Proposed Fix ```python # Change default from "" to [] tool_result_embeds = result.get("embeds", []) # Only include embeds attribute when non-empty embeds_attr = f' embeds="{html.escape(json.dumps(tool_result_embeds))}"' if tool_result_embeds else '' ``` I have a PR ready with this fix. ### Logs & Screenshots Browser console error: ``` SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data ``` Stored message content showing the problematic attribute: ```html <details type="tool_calls" ... embeds=""""> ```

GiteaMirror closed this issue

2026-04-25 09:03:42 -05:00

GiteaMirror commented

2026-04-25 09:03:43 -05:00