Some OpenAI-compatible chat/tool flows can produce function.arguments as an object or omit it. The Ollama conversion path previously called json.loads unconditionally, which raised before the request could be sent.
Changelog Entry
Description
Fix Ollama payload conversion for assistant tool calls whose arguments are already decoded or missing.
Added
Unit coverage for tool-call argument conversion in convert_messages_openai_to_ollama.
Changed
None.
Deprecated
None.
Removed
None.
Fixed
Prevent json.loads from raising when tool-call arguments are already a dictionary or are omitted.
Not applicable; backend payload conversion change.
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.
## 📋 Pull Request Information
**Original PR:** https://github.com/open-webui/open-webui/pull/24826
**Author:** [@pragnyanramtha](https://github.com/pragnyanramtha)
**Created:** 5/17/2026
**Status:** ❌ Closed
**Base:** `dev` ← **Head:** `codex/ollama-tool-call-arguments`
---
### 📝 Commits (1)
- [`106f919`](https://github.com/open-webui/open-webui/commit/106f91925f67db2effbb73ab626dc12fb7245272) Handle decoded Ollama tool call arguments
### 📊 Changes
**2 files changed** (+80 additions, -2 deletions)
<details>
<summary>View changed files</summary>
➕ `backend/open_webui/test/utils/test_payload.py` (+70 -0)
📝 `backend/open_webui/utils/payload.py` (+10 -2)
</details>
### 📄 Description
## Summary
- Handle OpenAI tool-call arguments that are already decoded or omitted when converting chat messages to Ollama format.
- Add focused payload conversion tests for JSON-string, decoded-dict, and missing tool-call arguments.
Relates to #23907.
## Why
Some OpenAI-compatible chat/tool flows can produce `function.arguments` as an object or omit it. The Ollama conversion path previously called `json.loads` unconditionally, which raised before the request could be sent.
# Changelog Entry
### Description
- Fix Ollama payload conversion for assistant tool calls whose arguments are already decoded or missing.
### Added
- Unit coverage for tool-call argument conversion in `convert_messages_openai_to_ollama`.
### Changed
- None.
### Deprecated
- None.
### Removed
- None.
### Fixed
- Prevent `json.loads` from raising when tool-call arguments are already a dictionary or are omitted.
### Security
- None.
### Breaking Changes
- None.
---
### Additional Information
Validation:
- `TMPDIR=/tmp PYTHONPATH=/home/ubuntu/gh-pr/open-webui-worker-next/backend uv run --no-project --python 3.12 --with pytest --with python-mimeparse --with Markdown --with beautifulsoup4 --with cryptography --with-requirements backend/requirements-min.txt pytest backend/open_webui/test/utils/test_payload.py -q`
- `TMPDIR=/tmp uv run --no-project --python 3.12 --with ruff ruff format --check backend/open_webui/utils/payload.py backend/open_webui/test/utils/test_payload.py`
- `TMPDIR=/tmp uv run --no-project --python 3.12 --with ruff ruff check backend/open_webui/test/utils/test_payload.py`
### Screenshots or Videos
- Not applicable; backend payload conversion change.
### Contributor License Agreement
- [x] 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.
---
<sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>
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📋 Pull Request Information
Original PR: https://github.com/open-webui/open-webui/pull/24826
Author: @pragnyanramtha
Created: 5/17/2026
Status: ❌ Closed
Base:
dev← Head:codex/ollama-tool-call-arguments📝 Commits (1)
106f919Handle decoded Ollama tool call arguments📊 Changes
2 files changed (+80 additions, -2 deletions)
View changed files
➕
backend/open_webui/test/utils/test_payload.py(+70 -0)📝
backend/open_webui/utils/payload.py(+10 -2)📄 Description
Summary
Relates to #23907.
Why
Some OpenAI-compatible chat/tool flows can produce
function.argumentsas an object or omit it. The Ollama conversion path previously calledjson.loadsunconditionally, which raised before the request could be sent.Changelog Entry
Description
Added
convert_messages_openai_to_ollama.Changed
Deprecated
Removed
Fixed
json.loadsfrom raising when tool-call arguments are already a dictionary or are omitted.Security
Breaking Changes
Additional Information
Validation:
TMPDIR=/tmp PYTHONPATH=/home/ubuntu/gh-pr/open-webui-worker-next/backend uv run --no-project --python 3.12 --with pytest --with python-mimeparse --with Markdown --with beautifulsoup4 --with cryptography --with-requirements backend/requirements-min.txt pytest backend/open_webui/test/utils/test_payload.py -qTMPDIR=/tmp uv run --no-project --python 3.12 --with ruff ruff format --check backend/open_webui/utils/payload.py backend/open_webui/test/utils/test_payload.pyTMPDIR=/tmp uv run --no-project --python 3.12 --with ruff ruff check backend/open_webui/test/utils/test_payload.pyScreenshots or Videos
Contributor License Agreement
🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.